Odd starting behavior of S404.114 at zero degrees and below!

February 13th, 2014.


Gentlemen:



The last couple of cold snaps have revealed an odd behavior trait on my 1963 Swiss Cargo Unimog with pertronix ignition and electric fuel pump set up. At zero degrees F or below, the truck will crank, but will not fire, and within a very few seconds she will flood out with the choke applied. She will not start at anywhere near that low unless the choke is applied, and what I am thinking is that between the oil bath air cleaner and the low temperature, the carburetor is not vaporizing the gas enough to allow the truck to fire it.
This truck sits outside, unprotected from the wind or the weather (it's much too tall for my garage), and as additional information, one starting battery is from 2008 and one is from 2010. When the temperature reaches four or five degrees above zero, she will fire and start with some small difficulty (rough running for the first half minute or so). When she refused to start at -10*F, the solution was to apply for 15 or twenty minutes a 250W worklight in the cab to warm the carburetor, and then she fired right off.
Did M-B ever make a block or cooling system heater for the S404.114's? I have seen some attempts to apply immersion heaters to the block, but that requires one of the freeze plates to be modified to take a block heater. How does M-B address this situation on the S406/408/412 and U1300L's when they have diesels (as the S404.114 seemed to be mostly gas engine trucks)?

Hopefully Wolf Dose will see this and add something to the discussion, as he does seem to be conversant with the S404.114 series...

Maybe change it back to stock? My truck is all stock and all I do is pull the choke out and not touch the gas and after sitting for a couple months it'll start with maybe 10 seconds of turning over.

If my 404 has been sitting a while I always hand prime the pump with the lever on the pump and it takes right off, I figure it saves on the starter to! You are not pumping the accelerator pedal while using the choke are you? That is a NO NO just about guarantees flooding every time!
KK

Mercunimog404 said:

Maybe change it back to stock? My truck is all stock and all I do is pull the choke out and not touch the gas and after sitting for a couple months it'll start with maybe 10 seconds of turning over.

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Yes, that´s it a Unimog starts normally., even when it is very cold. The Pertronix will help, the problem might be the electric fuel pump!?
The 404 of the Bundeswehr have a heating system for the engine, but I think the Swiss Unimog don´t have?
Anyway... normally the Unimog has to start without it even at 0° F...

Karl kostman said:

If my 404 has been sitting a while I always hand prime the pump with the lever on the pump and it takes right off, I figure it saves on the starter to! You are not pumping the accelerator pedal while using the choke are you? That is a NO NO just about guarantees flooding every time!
KK

Click to expand...

Hand prime on the carb?

Couple of things: Flooding should never occur if choke (actually a separate multi-orifaced 'enricher circuit') is operating correctly. As already mentioned, don't touch the petal.

Be sure your electric fuel pump is not over-pressuring the carb. The float needle valve only has to handle about 2 psi with the mechanical pump. Most electric pumps have pressures much higher than that. NAPA sells a little regulator settable to 2 psi.

Get a couple of matched batteries. Loss of cranking speed makes a big difference in starting any vehicle. 404 mogs are no exception. The Pertronix is a blessing, stick with it.

I have never heard of an electric MB block heater. Many of us 404 owners have added them. There's an access plate on the right side of the engine, near the front, kinda in behind and below the exhaust manifold. It's a plate with 6 bolts and a gasket. This is a good place to add a block heater. Fabrication is required, and 2 of those bolts are a b&^%$ to get to. I just did one last week, a block heater that was leaking.

404's will typically start at -20 F when nothing else that's old will start. (BTDT when I lived in Denver)

Bob

February 14th, 2014.

Some very good ideas, but gentlemen, it is not possible to use the M-B Mechanical fuel pump on this truck. You may ask why? Illinois only has 10% Ethanol added unleaded gas, and the truck destroyed 3 mechanical pumps (new M-B units) in the first three months here. Nobody makes silicone rubber rebuild kits for the carb or fuel system related rubber items, and the gas gradually destroys the original butyl rubber MB used.
The current pump is a high capacity 24 VDC marine unit, as not reliable units are made in 24 VDC that can keep up with the fuel demands at high speeds or high operational angles. It operates through a fuel bypass ressure regulator, so when the carb is not demanding fuel, it sends the excess back to the tanks, but the carb is getting about 3.5 to 4.0 lbs on the inlet. The truck will start at 4 to 7*F above, no issues, it is when the truck is at zero F and below that it will not fire, and it is due to the plugs being wetted by gasoline as near as we can figure, as you can smell the gas when she tends to flood out.

The heat applied to the carburetor will start her right up at negative 15*F, but without it, this truck will not function. Obviously when new they probably could function, but I suspect 50 years of age, and the cold weather we get here of late is beating her down. Very few American trucks do well in that weather without the computer controlled engine, and even the wife's jeep can be hesitant with the computer controls at 5 *F and below...

Unlike most Unimogs of this age and type, this one runs daily, under all conditions, and racks between 4500 and 6500 miles per year on and off road. The Pertronix was used, (and I am not sold on it), because at 35 MPH and above running for hours at a time, the original MB ignition did not perform well and tended to burn out the breaker points. Remember, for an S404.114 not to be a road hazard here, it has to hold 50 MPH for hours on end in transit, with stock axles.
The freeze plates seem to be where the block heater will have to be applied, and the difficulty is figuring out how to get one in there that won't touch some internal part in the engine. On our (diesel) locomotives, we put a heater and separate pump in the cooling system, but the S404.114 has the cooling system from hades when you look at its complexity....

Hi Kyle,

Maybe time to back up and look at other possible reasons for the MB pump trouble. 10% ethanol should not kill pumps at the rate of one per month. 10% ethanol is common everywhere outside IL. Lots of 404 owners use regular pump gas and still have original pumps. I run 10% ethanol most of the time and two trucks have been running it since ethanol was first added. No pump failures.

Did the diaphragms rupture? How about the stroke length on the pump? Are the diaphragms possibly being over stroked? Are any spacers between pump and block in place?

If it's not diaphragm rupture, are you possibly getting hose residue into your pumps that would block the valves? (I have had cheap fuel hose dissolved by ethanol)

As you said, wet plugs say 'too much fuel' so all is not perfect in your setup. Can you reduce input pressure to the carb below the 3.5 to 4 you have (twice normal)? The carb really might still be leaking fuel past the needle valve into the manifold. Two PSI or less is normal (measured by gauge).

Playing devils advocate here (we have known each other a long time) why do you need a high capacity marine fuel pump for an M-180 engine (2.2 L, 134 CI)? They just don't use that much gas even wide open. Your hi-cap pump may be doing more than you want it to? I use a cheap Facet 24v impulse-type pump when needed for vapor lock and still have to regulate it down to 2 PSI.

Check the main butterfly valves (one per venturi) to be sure they are closed while starting. You are no doubt aware that these carbs are not 'choked' by forcing the butterflies closed to reduce air (increase fuel/air), as most chokes do.

How is your choke/enrichener working? Do you refrain from doing any accelerator pedal movement before starting? The accelerator pump will flood a cold engine. With a properly operational enrichening circuit you should hear a high pitched sucking sound when the engine first starts and is drawing the correct fuel mixture through the choke orifice. That turbulence assists mixing/atomizing the cold fuel. If you don't hear that whistle then there's a good chance your choke circuit is not functional.

Hope something here helps.

Bob

X2 ^^. We have minimum of 10% ethanol in Nevada and my truck doesn't have any issues with it. I've had it for 7 years and it sits a month or two at a time without running. If starts right up each time. There is an underlying issue. My truck is dead stock and it has the original fuel pump.

February 24th, 2014.

Gents:

When the truck was transferred here from Texas under its own power in 2010, the carb nor the fuel pump had ever given any trouble and they had been gone over by Nick Rawlings down in Texas at the Mog Shop. The problems started almost instantaneously with the first fuel loads up here, and went down here from there. If you doubt the fuel pump destruction, just ask Michael Smith at Unipaser and Scott Ingram at Expedition, they had never seen pumps taken out at that rate.

The ethanol will destroy the Buytl rubber parts in the fuels system, and it gradually strips the tanks protective coats out also, and it then dumps them into the pump and the carb (the screen filters will not handle that degree of particles. The marine pump is a better grade unit then the Facets, which I would not use on a go cart. At high throttle settings (the trip from Texas was run at about 90% maximum opening to hold interstate speeds, the small electric pumps will not deliver enough fuel to the carb.

The Holley bypass regulator returns the fuel to the reserve tank, again, even with the smaller electric pumps, I was losing pressure regulators at about every six months, and I doubt they were doing the job much better. Also the Holley is currently used on many stock car engines with electric pumps and carbs, and I will say that the Unimog is not sluggish on acceleration or hill climbing at present.

Contrary to what many of us believe on here, The S404.114 and M180 engine was never intended to run any ethanol in any amount in its fuel supply. The Mercedes Benz engineers that I had a very long discussion with in the main Unimog plant in Germany said that the truck could not survive on any Ethanol at all, and they have no silicone rubber rebuild parts whatsoever as these trucks were designed for either Benzine or straight leaded gasoline. The only reason most American antique cars have survived so far is that the rebuilding companies (parts makers) have developed silicone rubber based fuel system rebuild parts, but then there are a lot more of the various American cars then there are Unimogs out there.

Otherwise, when its 2- 5*F+ and above, the truck will start in about three revolutions of the engine if the choke is set correctly, and once it achieves operating temperatures, it will start at those temperatures in less then two revolutions.
Below zero, there is almost no way to set the choke where she is not getting too much fuel. Admittedly the choke system is not the butterfly valves were are used to, but then neither is it the equal of the computer controlled chokes either, and the wife's 2006 Jeep Wrangler was none too happy at that cold temperature on the starts, either. The pity is that MB never considered extremely low temperature starting and did not design the block for heater units. I will say that when the heat is applied to the carb at minus 15*F, after about ten or fifteen minutes it will start and will continue to do so once the engine is warmed up.
I would wonder what the MB Diesel Unimogs do to handle sub zero starts...

saddamsnightmare said:

February 24th, 2014.

Gents:

When the truck was transferred here from Texas under its own power in 2010, the carb nor the fuel pump had ever given any trouble and they had been gone over by Nick Rawlings down in Texas at the Mog Shop. The problems started almost instantaneously with the first fuel loads up here, and went down here from there. If you doubt the fuel pump destruction, just ask Michael Smith at Unipaser and Scott Ingram at Expedition, they had never seen pumps taken out at that rate.

The ethanol will destroy the Buytl rubber parts in the fuels system, and it gradually strips the tanks protective coats out also, and it then dumps them into the pump and the carb (the screen filters will not handle that degree of particles. The marine pump is a better grade unit then the Facets, which I would not use on a go cart. At high throttle settings (the trip from Texas was run at about 90% maximum opening to hold interstate speeds, the small electric pumps will not deliver enough fuel to the carb.

The Holley bypass regulator returns the fuel to the reserve tank, again, even with the smaller electric pumps, I was losing pressure regulators at about every six months, and I doubt they were doing the job much better. Also the Holley is currently used on many stock car engines with electric pumps and carbs, and I will say that the Unimog is not sluggish on acceleration or hill climbing at present.

Contrary to what many of us believe on here, The S404.114 and M180 engine was never intended to run any ethanol in any amount in its fuel supply. The Mercedes Benz engineers that I had a very long discussion with in the main Unimog plant in Germany said that the truck could not survive on any Ethanol at all, and they have no silicone rubber rebuild parts whatsoever as these trucks were designed for either Benzine or straight leaded gasoline. The only reason most American antique cars have survived so far is that the rebuilding companies (parts makers) have developed silicone rubber based fuel system rebuild parts, but then there are a lot more of the various American cars then there are Unimogs out there.

Otherwise, when its 2- 5*F+ and above, the truck will start in about three revolutions of the engine if the choke is set correctly, and once it achieves operating temperatures, it will start at those temperatures in less then two revolutions.
Below zero, there is almost no way to set the choke where she is not getting too much fuel. Admittedly the choke system is not the butterfly valves were are used to, but then neither is it the equal of the computer controlled chokes either, and the wife's 2006 Jeep Wrangler was none too happy at that cold temperature on the starts, either. The pity is that MB never considered extremely low temperature starting and did not design the block for heater units. I will say that when the heat is applied to the carb at minus 15*F, after about ten or fifteen minutes it will start and will continue to do so once the engine is warmed up.
I would wonder what the MB Diesel Unimogs do to handle sub zero starts...

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It gets cold in Germany.

February 24th, 2014.

Note to post no 10 above. When the mechanical fuel pump was removed, it and its spacer and drive pin were set aside in the box the last pump came in, and a new cover was machined to block the fuel pump mounting pad with reuse of the original screws and a new gasket. This truck has also had to have the three way fuel valve replaced after coming up here (gaskets disintegrated) and all hoses have been replaced with new American standard hose for ethanol based gas. I can also tell you that the carb mounting gasket on the base is starting to fail slowly, as the drain plate is often slightly most with the screws set up. This is one of the original items on the truck that Nick went over in Dallas due to old age degradation (most Swiss trucks sat too much).
As hard as this truck gets run daily, you would figure she would start all the time, every time, and does so 98+%, just not reliably at sub-zero. About the only thing that would cause me to dump the truck is the cold start issues (if I lived in Alaska), otherwise this truck is much more reliable then many a younger truck.She averages about 4 miles a day, five days a week.

saddamsnightmare said:

February 24th, 2014.

Note to post no 10 above. When the mechanical fuel pump was removed, it and its spacer and drive pin were set aside in the box the last pump came in, and a new cover was machined to block the fuel pump mounting pad with reuse of the original screws and a new gasket. This truck has also had to have the three way fuel valve replaced after coming up here (gaskets disintegrated) and all hoses have been replaced with new American standard hose for ethanol based gas. I can also tell you that the carb mounting gasket on the base is starting to fail slowly, as the drain plate is often slightly most with the screws set up. This is one of the original items on the truck that Nick went over in Dallas due to old age degradation (most Swiss trucks sat too much).
As hard as this truck gets run daily, you would figure she would start all the time, every time, and does so 98+%, just not reliably at sub-zero. About the only thing that would cause me to dump the truck is the cold start issues (if I lived in Alaska), otherwise this truck is much more reliable then many a younger truck.She averages about 4 miles a day, five days a week.

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I'm telling you. I have had 0 issues with 10% here. Knock on wood. I've been using it for 7 years now. It'll sit for months and start up. I know ethanol sucks. There has to be other issues. My body has one here as well and has no issues with ethanol either. So I don't know. Maybe your hear riser is stuck open or something.

February 25th, 2014.




Unimog S404's have heat risers? My air intake is straight from the air cleaner to the carb, and the carb is right on top of the intake manifold. The exhaust is straight from the exhaust manifold to the front of the muffler with no taps anywhere for an American style heat riser and no thermal restrictor valve like an American truck.

I had a USMC M422-A1 that had heat risers to the carb, and my 1970's to 1980's trucks have had heat risers and chokes, but this S404.114 is pretty much the way the Swiss got if rom MB in 1963, and they were cheap enough to buy nothing extra beyond the cab and frame. They were so cheap they did not get the extra fuel gauge for the main tank, but went for the "dipstick" option on the passenger door. Swiss Army Unimog No. 443 in Dallas was identical to mine mechanically and as to condition, but it did not have the wheel position indicator (VDO) that mine has on the steering column, so the units may have made some changes over time.

Tomorrow will be 2*F above zero, so I will see if she will kick over first thing.

Oh, I am looking for the little round blocker plate that goes in the cab floor just behind the fuel valve and under the head of the handbrake handle. That dipstick mechanic lost mine, and he's willing to pay for a new one, I just don't have the extra cash to pay MB prices... This morning a sparrow got into the cab, as they have a habit of sitting up under the cab and bed to get out of the weather, and I guess the little bloke flew up through that hole, but couldn't get out until I opened the cab doors...That's a first in 7 years of ownership! Swiss S404.114 as a wildlife sanctuary!

saddamsnightmare said:

February 25th, 2014.




Unimog S404's have heat risers? My air intake is straight from the air cleaner to the carb, and the carb is right on top of the intake manifold. The exhaust is straight from the exhaust manifold to the front of the muffler with no taps anywhere for an American style heat riser and no thermal restrictor valve like an American truck.

I had a USMC M422-A1 that had heat risers to the carb, and my 1970's to 1980's trucks have had heat risers and chokes, but this S404.114 is pretty much the way the Swiss got if rom MB in 1963, and they were cheap enough to buy nothing extra beyond the cab and frame. They were so cheap they did not get the extra fuel gauge for the main tank, but went for the "dipstick" option on the passenger door. Swiss Army Unimog No. 443 in Dallas was identical to mine mechanically and as to condition, but it did not have the wheel position indicator (VDO) that mine has on the steering column, so the units may have made some changes over time.

Tomorrow will be 2*F above zero, so I will see if she will kick over first thing.

Oh, I am looking for the little round blocker plate that goes in the cab floor just behind the fuel valve and under the head of the handbrake handle. That dipstick mechanic lost mine, and he's willing to pay for a new one, I just don't have the extra cash to pay MB prices... This morning a sparrow got into the cab, as they have a habit of sitting up under the cab and bed to get out of the weather, and I guess the little bloke flew up through that hole, but couldn't get out until I opened the cab doors...That's a first in 7 years of ownership! Swiss S404.114 as a wildlife sanctuary!

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They do have one. Mine was was seized shut. I'm hoping just wiring it open will solve the vapor lock when it's over 100 degrees

Let me know how it starts.

February 26th, 2014.

Missed it today. It was 9*F when I kicked it over, and she started quick like always. Tomorrow should be colder (Ugh!) so I will give her another shot then. Where's the heat rise? As I said up above, my exhaust is straight from the manifold to the muffler with nothing in the way of restrictor valves to be seen anywhere, and its the original tailpipe to the front of the muffler.

I will say that she does give me h-ll in the summer in hot weather, but I attribute that to the carb sitting on top of the exhaust manifold, so she seems to vaporize the carb's contents when she sits after a long run. The Model T Ford used a similar set up to handle low octane gas, and it could get cranky at high ambient temperatures, but almost never at low temperatures.

The run up from Texas was done on 95-104*F days, 70/80 KPH, sometimes 90 for short bursts, and the truck ran eight to ten hours a day at road speed with no issues with the mechanical pump. The electric pumps, except for this last one, she has never been able to run those kinds of speeds or temps for those long hours, as she consistently outruns the fuel pump (the cube type electrics).

The reason I engineered the Holley pressure regulator and bypass is that the older inline electric pumps would consistently burn out due to the carb not needing a constant fuel flow to operate, and that would blow the pumps. so far, the bypass to the tank has helped this pump go a 100% longer so far in daily service (short distances and longer trips hauling the canoe).

Only the marine pump has enabled her to run at high speed for long and to pull hills a little better. I would love for one of the rebuilders to do silicone rubber gaskets, parts, and diaphragms for the MB pump, but that isn't going to happen anytime soon. The M180 gets a lot of grief from folks who have to have high power outputs, but for an early 1950's engine, it does pretty good dragging a 6100 Lb. truck around. The early MB diesels were often not much to write home about when placed in the Unimog.

If I would ever engineer an engine change out, it would likely be an MB diesel, or better yet a Deutz diesel, as I have had exceptionally good service from the Deutz on the railroad. I have one FL-914 -4 air-cooled that will start at -20*F without ether or glow plugs, so I so think that Deutz got that one right as it was sent over from the main plant in Germany.

At least a Unimog will teach you to swear in german from time to time.....

Hi Kyle,

Your system of holding required pressure at carb input but providing a return path for excess fuel back to the tank, is a good system. Bet you don't have too much vaporlock trouble. Your system makes moot my earlier comments about the marine pump being overkill.

I just added my anti-vapor-lock 10% Diesel to the 404 I've been driving. We hit 60's a couple of days ago and winter gasoline mix often boils at not much over that temp.

Bob

Kyle,

How do you account for the fact that ethanol is being used at 10% in numerous states, and fuel pump failures/fuel issues are NOT THE NORM with other 404s. As a parts dealer we do not see your truck being representative of the effects of ethanol on the vehicle. There are enough 404 in active use that if ethanol was destroying the trucks there would be far more discussion/people with the same symptoms/problems. Bottom line, we don't see it. Do we sell fuel pumps and rebuild kits....yes, quite a few. However, I can guarantee you that most customers are buying a single unit and rarely if ever are we hearing back from them with a second failure. I would expect fuel pumps to go bad on a 20-30-40 year old truck. Going bad 2,3,4,5 times and then the electric fuel pumps going bad, and the valves going bad...... Are you absolutely certain that something else is not going on? I do not think your experience is representative.

As for the fuel pumps...are you guys using the Facet 24V low pressure (2-3.5 psi) with the check valves. Facet #40274. We have been using these pumps without a pressure regulator without any problems. They are rated for 6000 hours from the manufacturer. They can sometimes be difficult to acquire....we just had a batch made up, but it seems to be a good pump, and doesn't require the bypass, regulator, etc.

Cheers,

Scott

expeditionimports said:

Kyle,

How do you account for the fact that ethanol is being used at 10% in numerous states, and fuel pump failures/fuel issues are NOT THE NORM with other 404s. As a parts dealer we do not see your truck being representative of the effects of ethanol on the vehicle. There are enough 404 in active use that if ethanol was destroying the trucks there would be far more discussion/people with the same symptoms/problems. Bottom line, we don't see it. Do we sell fuel pumps and rebuild kits....yes, quite a few. However, I can guarantee you that most customers are buying a single unit and rarely if ever are we hearing back from them with a second failure. I would expect fuel pumps to go bad on a 20-30-40 year old truck. Going bad 2,3,4,5 times and then the electric fuel pumps going bad, and the valves going bad...... Are you absolutely certain that something else is not going on? I do not think your experience is representative.

As for the fuel pumps...are you guys using the Facet 24V low pressure (2-3.5 psi) with the check valves. Facet #40274. We have been using these pumps without a pressure regulator without any problems. They are rated for 6000 hours from the manufacturer. They can sometimes be difficult to acquire....we just had a batch made up, but it seems to be a good pump, and doesn't require the bypass, regulator, etc.

Cheers,

Scott

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X2

February 28th, 2014.

Scott and company:

Your point is well taken, but you and I have had this discussion many times before, and you have never been able to either prove or disprove why the mechanical pumps failed, yet between your shop and Michael Smiths, the truck did go through three mechanical pumps in three months, and they were either new or supposedly MB rebuilt units. Do explain how the truck ran in Texas with no issues on regular unleaded, and started acting up on 10% ethanol almost immediately.

Perhaps I have more experience on generally older 1920-1960 era US Gas engines, and almost every one of them that had a mechanical fuel pump loses it quickly when exposed to ethanol. The only thing that has saved the older US cars is that there are more of them, hence the silicone rubber rebuild kits for carbs and pumps. You may keep the Facet pumps, I had one on there before you stopped carrying them, also a Pertronix manufactured cube pump, none of them lasted a year in daily high speed (road service) up here.

The current technology in drag racing and stock cars that apply a carburetor (and they often do so for performance), have pretty much all settled on the Holley regulator and bypass set up to handle an electric pump on a set up intended for mechanical pumps. This ensures that the carburetor gets whatever amount of fuel it needs and the rest is turned back to the tanks. Plus I am using a better cartridge filter then the screen filter on the truck could handle as regards to micro sizes.

The German engineers at MB at the Unimog plant simply stated to me after a considerable discussion, that the original M180 gas engine in the Unimog was not intended to handle ethanol in any percentages whatsoever, and they had no sources for conversion parts to handle that. AND the tank linings are not intended to handle it either. So short of cleaning and relining the tanks (they have been cleaned for operational purposes at least twice), the linings will continue to erode on exposure to Ethanol. I will set the MB engineers against any shop in the US as regards knowledge of the Unimogs, and further I will here challenge you parts dealers to go out and get any respected US parts maker to get the silicone rubber rebuild kits out for the pumps and carbs....

I was not interested in replacing the fuel system, but a truck that never had problems in Texas developed them here within weeks. Almost every 1950-60 carb and engine exposed to the Ethanol develops issues. I would rather she was able to run on the original technology, but that hasn't happened, and I doubt many southern west coast Unimogs et much -15*F operational time as a rule.

As an aside, respectfully, I had offered to return the pump for your examination and credit, but that was at least two years ago, and I firmly believe that the truck is getting blame for the wrong gaskets used in rebuilding the pumps. The MB engineers were pretty emphatic as to the effects of Ethanol on the engines, and they have no real interest in delving into a forty year old obsolete product. I have noticed most west coasters convert to propane and such different fuels, seems like the gas engine should work on real gasoline or benzene (later unobtainable here in the US).

I saved the spacer, pump and new drive pin, which was another little MB inanity with no bushings for wear compensation. The truck had 10,000 miles equivalent when I bought it, it has at least 40,000 now, and if it is above zero, it fires right off, below, not so hot. This weekend may give me a chance to force the start below zero, that remains to be seen. Seems like the engine would benefit from the application of a block heater, but then MB didn't think of that either.

Oh, while in passing,the Pertronix ignition system is not great shakes for an off road truck, as it is not particularly a heck of a lot more reliable then the MB one is, when it fails, the truck is every bit as dead as a doornail (just like every other electronic system). I would be doubtful about going very far cross country without a spare one of these on the truck either.

That is just my opinion, but I have run a heck of a lot larger and older machinery then this with no problems, I would love to see the long term cumulative damage on an M35A2 multifuel system exposed to 20% volume of Ethanol laced gas, and that was a truck designed to handle almost anything in regards to fuels.