MEP-018A: ol' reliable dying, advice sought.

OK, got my hands on this back in '05. Back in '09 the regulator fried and I replaced it with an electronic unit (see older posts). Have never had the need to use it but start and run it every month, under load.
Recently, it's been either cutting out altogether, by first slowing down like it's running out of fuel, but that can't be it cuz I have it running on LP, or it just quits. No attempt will get it to fire again. I check the LP flow and it is flowing, try to fire with ether but no luck. It will fire again only after I let it sit for awhile.
Sounds like it's overheating. I have all covers in place and the location provides plenty of airflow around it.
Is there some sensor in line someplace that would be causing it to shut down if it gets too hot? If so, are they prone to failing like the regulators do? Or, is there something that I need to look into otherwise, like something else altogether?
It's prime-time hurricane season here and I have invited a lot of folks to spend time here in the safe house in case we get hit, but 20-30 mins of electrified comfort out of every hour is unacceptable.
Any thoughts/advice is most welcome.
Thanx much.
Ken

Not familiar with that specific model since I work only on the diesels, but a few possibilities come to mind ("generic" to gas engines) as follows:

1. As to the overheating possibility, what is the shutdown set point temp for an overheat condition? With that info in mind, check the temps adjacent to the sensor and other areas (cylinder head, cooling fins etc.) and compare to the set point. Having an IR thermometer here is handy. I doubt you're having an overheat condition though.


2. I've seen air-cooled engines with excessive cylinder bore wear crank up fine and run awhile until the bore opens up to a point where compression decreases and the engine has no power and will shut down even under light load. Right after shutdown, I suggest you perform a compression test on each cylinder.

3. Right after shutdown (do this in conjunction with the compression test), you can install the plugs back into the boots, ground them out and observe spark while cranking the engine. If no spark is seen or you see a weak spark, then it could be an ignition problem, related to temperature--capacitor or coil going out?

4. Going back to temperature, (and if you did find an overheat condition) could the timing be advanced or retarded some? Both of these will cause excessive temps.

I'm sure others familiar with this specific unit may add more info and hopefully can share issues they've run across for that model.

Edit--Forgot to ask if you had a manual for the set. Then you would be able to locate any sensors and what set point is.

Just one thing that may or may not be related to your problem, rotor insulation failure seems to be very common on the MEP-018a for some reason, there was a guy either on here or over on the smokstak board a couple of years ago that had one that the rotor went bad on, and he ended up buying 2 or 3 more used rotors / parts generators before getting one with a good rotor. As well as at least 2 other reports I know about with bad rotors on this model.

Ike

Just to add a few ideas

Does it do this only when running under load or will it demonstrate the same tendency if running with no load ?

Is it a smooth gradual slowdown, like closing the throttle or rough running and fighting for life, missing and stumbling, or just die like you turn the run switch to off.

Are you sure the baffles for the oil pan heater and air cleaner are in the “warm” weather position.

When it dies will it even crank ? If it will crank have you tried starting it with the “run/stop” switch in the “emergency” position.

Thanx all for the advice. DieselBob: It dies either way: sometimes a slow death (gradual slow-down, then it quits), other times, it just shuts down. When it DOES die, it will crank (so I really don't think it's heat or valve related) but won't fire. I WILL try using the emergency position next time tho.
BTW, I have never experienced a failure of this sort with ANY gas engine, ever.

How is the flow of gas controlled? Is it starving for fuel?

How is the oil pressure?

May not be related to the stalling problem, but if hard to start, the compression could be an issue...it was with mine.

When you say 'gradually slows down' do you mean that it starts sputtering, gets worse and worse, and eventually quits, or more like it is slowly being throttled down? If the former, I'd wonder about a thermal intermittent failure of either the coil or a condenser. If the latter, I'd say you've got a fuel starvation problem and have a look at the fuel pump, vapor lock, crud covering up the fuel pickup in the tank over run time, collapsing lines, etc.

All of these problems would result in a no start condition until the machine cooled down or something moved around in the fuel system.

He is running on propane gas...

cranetruck said:

He is running on propane gas...

Click to expand...

Still a good thing to check for steady gas flow though....I've seen LP regulators malfunction and restrict fuel flow, though never had it come and go with temperature or run time. Also seen the gummit' req'd OPD valves malfunction--in case he's using a tank with that type valve....

What size and how much propane is in your tanks, might be a fuel vaporization problem

You'd think he'd have seen that in the winter first, though. Did you do long run testing (or long runs) in winter? What kind of vaporizer (if any) does the LP system use?

steelypip said:

You'd think he'd have seen that in the winter first, though. Did you do long run testing (or long runs) in winter? What kind of vaporizer (if any) does the LP system use?

Click to expand...

He is in south Florida, there is not that much difference there between summer and winter (partly depending on how far south, and how close the coast)

ike

p.s. I once spent the whole month of December (20+ years ago) in south Florida (5 week training course for work), housing for all of us doing the course was an older pink extended stay motel on the coast, nice enough place, had a 2 burner stove, mini fridge, 5 minute walk to the beach, etc. It was air conditioned, but did not have heat, and of course I was there for their first freeze in over 10 years. As least that little stove took the edge off the cold in the room for the 2 or 3 cold days we had.

Well, yes, I am in SoFla, very hot here now, and this thing, when it works, will run the whole house including central A/C. I have this connected to city gas (which is piped in LP, BTW, not natural) which also supplies the stove and water heater, so, if the big one hits, I can be comfortable when FPL cuts my power for 2 weeks again. That is, of course, provided the **** thing works.
As I've said, it will either slow down, then quit, or just shut down. And either way, when it happens, I can't even get it to light up with a shot of ether. I will check fuel flow again, but I can use the bleed valve (like a primer button) on the regulator to give it a shot of gas. I can hear it flowing, but it won't light up on that either. The oil gauge shows sufficient pressure when it DOES run, and it shows '0' when not running so I'd guess the gauge is working, so I can't think it's a low-pressure shut-down, but at this stage, I'll check ANYthing.

If you can't get it to light with ether or with a shot from the bleed valve, it almost has to be an ignition problem. A lot of them are thermal or vibration intermittent problems.

Definitely would recreate the symptoms and when its acting up do a spark test with something like this and checking for a quality spark . Compare findings to when its cooled off and runs well. Guessing no spark or very weak.


http://www.amazon.com/Thexton-404-A...8&qid=1376067498&sr=8-3&keywords=spark+tester

Check compression, low compression = no/difficult start.

Thanx to all who've responded. Will be checking spark and compression after running (dying) and report back with my findings. Hope it's not some sensor or shutdown switch somewhere: I HATE looking for electrical gremlins, even more than I hate rebuilding engines. But neither is quite as bad as putting on a hot-tar roof in the afternoon in August in SoFla!

Got into it this weekend, without a happy ending. First, check the simple things: was down 2 quarts (yeah, I know) of oil, thought MAYBE it's causing the low-oil sending unit to kill it when it gets hot cuz not enuf oil. Then, pulled the plugs in preparation for a compression check (cold, then hot). One plug was a bit oily, others were ok; cleaned them and re-gapped (from a bit over 32 down to 30 thou. Checked for spark: ok, quite strong. Also decided to check valve clearance (manualk sez like 7 thou), then realized they are hydraulic lifters so no way to adjust. Then I made my big error: decided to check the condensor and point gap. Condenser checked ok, points wre a bit close but not pitted; re-gapped to 15 thou (didn't have a 14 thou gauge). Tried my ****dest to put that magneto back together and have it pointing to #1 when it fires but I got it wrong. So now, no run at all, gotta take that thing apart and figure out how to set it up. Also, I've worked with many mags in my lifetime but never one like this. Maybe it's broke, but it seems like it winds up a spring to about 180 degrees, then snaps to make the spark. The gear moves about 180, then stops moving until this snap. Strange. And, it only sparks every 180, not 90 degrees, which would make more sense to me to fire 4 cylinders. So, before I waste a whole weekend trying to set this thing up again: s it broken?

Sounds like the magneto on my Gravely, which is a typical Wico Mag. When cranking, it winds up like that so when it snaps there's enough speed to make a spark. When it speeds up, it quits doing that and runs normally. A four cylinder 4-stroke engine fires every 180 degrees, since each cylinder fires every two turns of the engine.

Well, I 'fixed' it. Not in any kind of good way. No matter how many times I read the info on the mag and timing in TM 9-2805-259-14, and after countless times pulling the mag and governor trying to set the timing marks on the mag-and-camshaft gears and on the timing marks on the flywheel, I cannot seem to get the timing to line up where it should. I can get it to fire on #1 at the timing mark on the flywheel by static timing (turning the crank by hand) but when I spin it with the starter motor, the timing mark appears sometimes where it should be and other times it is all over. At least I THINK it's the timing mark: the manual sez to line up the mark but there is a normal-looking set of timing marks (w/retard and advance) and then a single mark about 2" ccw of that that sez TDC, and I don't know which is right.. I tried both to no avail. I think I really fixed the mag when I took the cap off to check the point gap. I have no idea how to line up the gears that are inside there. I did get them set so that I can get a spark at #1 when I turn the mag by hand, but it just doesn't seem to work right when installed. I see nowhere in the manual how to time those gears. Unless I can figure that out, looks like I'm buying as mag somewhere. Maybe THEN I can get it to start again and THEN maybe I can go back to trying to fix the original problem of it dying on me!