Finally bought a MEP-831a

[DieselAddict]

Have you checked the air filter? Can you do a quick test run with the filter removed (assuming you aren't in continuous dusty conditions)? Look for anything obstructing the intake.

Black smoke is unburnt fuel. To add to Guyfangs list it can be caused by an air restriction in the intake or exhaust and also low compression.

 

[Guyfang]

Just finish draining fuel tank until the fuel pump couldn't pick up any more fuel, the pump has a very good rate of flow. I disconnected the fuel line right before the water separator filter, there is a bit of fuel left in the tank probably 1/8 gal in there. I filled the set up to 1/2 tank, I allowed the set to prime up for around 5 mins, fired it up same issues as before, black smoke. This time the set would only take 50% load 1500W.

List
1. Old/bad fuel - New fuel being used
2. Dirty fuel - when I went threw the set in December I cleaned out the fuel tank as best as I could. Gold flakes of metal probably from fuel gauge float were present. Not going to rule this out, maybe something was left in a fuel line.
3. Fuel line with pinhole - all fuel line were replace 6 months ago. no leaks are visible, but I'm sure your referring to a vacuum leak.
4. Fuel pump problem - seemed to have a great flow rate
5. trash in fuel tank- tank was cleaned.
6. Trash in the fuel filter - I never replaced that spin-on filter, going to NAPA tomorrow for that.

What is the best way to clean a fuel tank in your opinion? I may of not cleaned it well enough.

Thank you, Guyfang.

If it LOOKS clean, dump some denatured alcohol into it. If you can swirl it around, its good, then let it out. When its possible, I remove the tank, but on some gen sets that's not an option. If it doesn't look clean, it might be best to remove the tank and pressure wash it. THEN put in the denatured alcohol. It helps remove water.

 

[AfghanVeteran2010]

Thanks DieselAddict and Guyfang,

Things done today:
1. New Main Fuel water separator replaced wix 33583.
2. Removed air filter, no change in operation. Removed Air Cleaner Assembly heater was clean. Air intake duct had some soot in it.
3. Valve Clearance Adjusted, was off by a bit . Set to TM spec.
Seem to be less noisy now, still have black smoke under load. 1500W+
4. Attempted a Fuel Injection Pump Adjustment. see below for remarks


--Fuel Injection Pump Adjustment--
I removed the high pressure fuel line moved it over to side. Flywheel cover removed and I opened the actuator. I rotated fly wheel clockwise to T meets V mark. No fuel being pumped observed so I rotated the fly wheel around 6 times no fuel still, I recorded me rotating it 4 more time this time with electric fuel pumps on still no fuel. Am I doing something incorrectly? This is where I halted my progress for the time being.
I did not have this smoking until after I pulled the engine and replaced the fuel line. I'm starting to think some thing my of got caught in the injector pump. maybe when this is running it gets a enough fuel for 1500W but not 3000W. Maybe the injection lose pressure it needs at this demand and the fuel wont atomize. While I was turning fly wheel I push the decompression lever to allow me to turn the wheel more easily.

https://youtu.be/cHnzts61BZg

 

[AfghanVeteran2010]

I gave it another try when I use a towel to soak up fuel in the compression fitting on the Injection Pump I can see it being filled. I was expecting it to fly out of pump just by hand turning it, when I engage electric starter of flys out about a foot. I had my old injector hand so I hooked it up and turned it over to see how it atomized the fuel. Looked good to me. I doesn't make sense that a lack of fuel would cause black smoke over fueling or lack of air. air intake seems clear I couldn't look far enough to see to the valve. Must be the timing going to check that tonight or tomorrow. As for compression I cant hand turn it by hand with out hitting the decompression lever, I don't know if that means the compression is good enough. This is my first diesel engine. IF it has been running for these 8 hrs under this condition and the unknown of previous engines that the muffler has been under can running rich cause issues in the muffler. Or can it be burned out similar to wet-stacking. I did get the quote back for a muffler $399.99 USD now that's a pretty penny. I'll only get this if I'm positive that this is the cause.

 

[DieselAddict]

After all you've done I'm betting on timing or an injection (injector or pump) issue. You are covering your bases well.

 

[AfghanVeteran2010]

Just finished playing around with the Injector timing, seems to want to send fuel at the 4th mark which is 20 degrees. The TM says 16 to 18 degrees, between 3 and forth before the TDC position mark. I did this about 4 time and it was at 20 degrees every time.

4-11 Fuel Injection Pump Maintenance

8. Injection timing can be adjusted by adding or removing injection pump shims (7, Figure 4-14). If fuel is injected before a 16 degree rotation, add shims. If fuel is not injected until after a 18 degree rotation, subtract shims. Each 0.1 mm (0.0039 inch) shim changes timing by 1 degree.

Kinda confusing how it states that at least it is to me. So I pulled the Injection pump off the was only one shim installed, so I pulled it and reinstalled it now its at around 22-23 degrees. So I guess I should be adding shims to it right. I did fire it up still running the same.




Thank You

 

[AfghanVeteran2010]

Order 4 .1mm timing shims. Also it seems as the engine heats up to operating temperature to smoking gets worst. I'm tempted to order a injector pump as well. Good thing about theses Yanmar engines parts seem to be a fair price.

 

[Guyfang]

Yes, you can burn out the muffler, when it has a buildup of crud.

Warning!

I have seen a Brit friend of mine catch one on fire, when he tried to burn out the muffler. He started it up, loaded it down, and walked away. That BS fire resistant cover on the muffles WILL burn, it it gets hot enough. The carbon in the muffler, started to burn in the muffler. So be advised to kinda keep an eye on it. You don't have to sit on it, just every once in awhile eyeball it.

This incident provided no end to the fun we had with this poor guy.

 

[AfghanVeteran2010]

The muffler fire resistant cover was smoking pretty good the other day. This is a long shoot but does the military keep maintenance logs of equipment that has been sold off to auction. Kinda would like to see it history I know it was reset(of some kind) or half way threw it. Never worked in motor pool to know, just done PMCS and filling out DA 2404s.

 

[Guyfang]

No way. Records like that would never be kept long.

The heating up of the muffler could also be a sign of incorrect timing. So maybe the shims will correct that.

 

[AfghanVeteran2010]

Shims installed to about 17 degrees with original injection pump, no observable change to operation smoked under 3000 watt load. Replaced with new injection pump readjusted with shims to 17 degrees, still smoking. I replaced injector about 7 hrs set ago. Gen set was operated for a few mins then load applied 1500 then 3000 shortly after. I might be adjusting the timing incorrectly, I have search youtube and turned up nothing. I followed the TM to the letter. It might be time to look at the Yanmar manual again. Next thing the TM points me to on troubleshooting is possible piston / cylinder liner seizure. That has pita written all over it, not quite ready to jump to that solution yet. Assuming that that is not the cause for the time being only thing left is a restriction in the exhaust system, can i run the gen set with the muffler and the hood removed? Trying to minimize the mess it's going to make doing that. Any other ideas or recommendations.

Thanks everyone.

 

[DieselAddict]

Well, its going to smoke a little bit. How much is it smoking? Do you have a short video you can post?

Will it carry a full load now that you have tweaked everything?

 

[AfghanVeteran2010]

Double Post.

 

[AfghanVeteran2010]

as requested load is 3KW, for full load you mean 3000 watts right?

https://youtu.be/P2JZ2BHP4A8

 

[DieselAddict]

Hm. That is a little more smoke than I would expect. Not a lot more but a little more. Hm...

 

[AfghanVeteran2010]

Think I should try to run it for a few hours at 3KW ?

 

[DieselAddict]

I think you should. Since it will pull a full load I would see how it handles it for a while.

 

[AfghanVeteran2010]

Ran it for around 20 mins

After 2 mins
https://youtu.be/vi7oBCMNT-c

After 5 mins
https://youtu.be/GMhzOatqj68

After 14 mins - Bogged down
https://youtu.be/bH1mmc5JxFk

I reapplied load after a minute and gen set bogged out after a few mins, I repeated this 2 more times.

 

[DieselAddict]

What RPM are you running? Does the variable speed governor work?

 

[AfghanVeteran2010]

The actuator opens up full off of throttle plate under full load i've watched it before and its not making contact when the gen bogs down. Today it seem to be working when there is no load. I planed to set it to TM when smoking was solved, since it hasn't interfered with the throttle plate. Not sure on exact RPM when running.

Thanks