Yet another MEP003a Issue!

[dkpaintball]

Hey, again. I hate to be the guy that contributes nothing but always asks for help, but I dont know where else to go. It is much appreciated when you guys help me. So anyway, I have another issue i was wanting to ask about on my MEP003a. I run it on a daily basis basically now, but lately it has been having a lot of trouble starting. I will hold the glow plug for about 2 minutes then I will have to hold the starter for about 2 minutes constantly while it warms up or something. It will shut off immediately when I release the starter until I hold it for about 2-3 minutes, then randomly when it decides it wants to it will continue running after i release the starter switch. When its warm it doesnt do this as badly. I am leaning towards the glow plug being bad. Does this sound like a correct assumption? I really appreciate any input.

 

[ke5eua]

You should never run the starter that long. 30 sec max.

Glow plugs are for cold weather starting.

Is there any smoke coming out the exhaust when starting, white, black?

Has ether ever been used to assist starting?

Sounds more like a fuel issue as I'm pretty sure it isn't below 40 where your at.

 

[dependable]

30 to 60 seconds glow plug when not warmed up helps in most weather. But agree it sounds more like fuel issue. How often do you change the fuel filters? (and oil for that matter) I know you run this a lot, 100 hours (recommended service interval) adds up pretty quickly with daily use.

 

[Isaac-1]

There are a number of possibilities ranging from worn out engine with low compression, to a simple matter of the governor linkage getting stuck and not moving all the way. So the next question is does it smoke, while / after starting, and if so what color is the smoke?

 

[dkpaintball]

Thanks for the quick replies. When i Initially start it there is a small amount of white smoke that comes out. I have never used ether to start it. Also, the generator is not physically in sacramento. Its at about 6k ft elevation and its often times very cold when being started, like 30-40 degrees. Once i turn it over with the starter for about 15 seconds you can hear the change in the engine as if it is combusting, but when i release the starter switch it stops. So i continue to hold the starter until it stays on by itself, which can take 2 minutes sometimes. It feels terrible to do that. I am probably going to have the thing rebuilt in a few months when I can afford it but I was hoping maybe there was an easy fix. I can see maybe the fuel filters were clogged or something which caused this to happen. I will look into it. It just recently started to do this. Once it is going it runs fine though, for hours and hours. Thanks again for the responses and I will let you know how good your diagnosis was

 

[ke5eua]

Ahh, ok I understand the glow plug needs now.

Has anything been done to it as far as service and have you noticed any change in its running condition.

If you are familiar with a multimeter you can check the glow plug circuit fairly easily. Have someone activate the glow plugs and touch the positive lead to the wire on the plug and the other to ground. Put the vmm in dc and if the circuit is working you should see 24 vdc.

What about priming the fuel?

 

[Keith_J]

Sounds like oil pressure safety switch. What does the gauge read? If over 15 PSI, short the two connections to see if this works around the problem.

 

[Rapracing]

Sounds like oil pressure safety switch. What does the gauge read? If over 15 PSI, short the two connections to see if this works around the problem.

I'd start here as well. First is the oil pressure coming up? If not that would be the reason Also, my 002 had a bad connection at the switch causing it to do the same thing.

 

[cuad4u]

Do the glow plugs even work? Remove the wires from them and use a VOM to measure resistance from the GP tab to ground. It should be 5 ohms. If the GP's are open or if they are not getting 24V they might as well not be there at all. If the GP's are working, I agree you have a fuel problem. Check and or replace ALL fuel filters. Don't forget the one in the electric fuel pumps. Next pull the injectors and have them checked and repaired if necessary. This costs around $25 per injector. Next and hopefully last is the IP. Most of us just buy a rebuilt IP.

 

[Speddmon]

It's not a fuel issue. Kieth hit the nail on the head. It is either the oil pressure switch or the high temp shutdown switch. Both can be jumpered out to test and verify which one is the offending switch.

 

[Munchies]

IS the solenoid operating properly? This is a tell-all. If it works then your switches are ok. If it works and your not getting fuel, check the linkage. Make sure the throttle arm is able to travel to max throttle, and does so during starting. I think all but one of 50+ meps I have fixed have had the linkages out of adjustment, and quite a few fellow SS members have had the same issue. Very easy to overlook.

 

[ke5eua]

White smoke occurs when raw diesel comes through the exhaust completely intact and unburned. Some causes of this include


Faulty or damaged injectors
Incorrect injection timing (could be a worn timing gear or damaged crankshaft keyway).
Low cylinder compression (eg caused by leaking or broken valves, piston ring sticking, cylinder and/or ring wear, or cylinder glaze)

When white smoke occurs at cold start, and then disappears as the engine warms up, the most common causes are fouling deposits around piston rings and/or cylinder glazing.


Water entering combustion spaces will also create white smoke. Faulty head gaskets and cracked cylinder heads or blocks are a common cause of water entry, and are often to blame.

I know this is obvious for most of us, but I figured I would post it anyways since OP did state he had white smoke when starting.

 

[Isaac-1]

The quote above about water entering the combustion chamber would likely not apply here since it is a air cooled engine.

 

[ke5eua]

I know, I copied it from something and just didn't take it out.

 

[Speddmon]

IS the solenoid operating properly? This is a tell-all. If it works then your switches are ok. If it works and your not getting fuel, check the linkage. Make sure the throttle arm is able to travel to max throttle, and does so during starting. I think all but one of 50+ meps I have fixed have had the linkages out of adjustment, and quite a few fellow SS members have had the same issue. Very easy to overlook.

The fuel solenoid is NOT a tell all! The safety shutdown switches are bypassed by the master switch as long as you are holding it in the "start" position. As soon as you let it go back to "prime & run" the switches come back into play. Therefore, as Keith and I said, check the safety switches. If it shuts off as soon as you let go of the master switch, it is probably a safety switch.

 

[Munchies]

Maybe its just my headache or the fact the 002/003 market is drying up in the south so I havent touched one in a few months, but does the solenoid not retract/stay retracted while in the run position for a few seconds if the switches are good? If you have good oil pressure and its not overheating, mine have all stayed retracted for a moment until the oil pressure sensor opens at its preset.

Regardless, I am fine with being wrong. Check your linkage after you verify switch integrity. For a super fast starting onan, you need that throttle up ALL the way.

 

[Isaac-1]

It could be either or both, I have a similar slow starting MEP-003a, although not as bad as this one, and part of the problem seems to have been caused by the governor arm mostly unscrewing the linkage (lock nuts loose, making it about an inch too long) this kept the governor from applying full throttle. Fixing the linkage significantly improved the slow start, slow to rev up and build oil pressure problem. If yours is like mine it may be multiple factors causing the slow start, slow to rev condition, first I changed out 2 of the diesel injectors which helped noticeably, then I changed out the type 1 starter for a new type 2, which helped a little more, and most recently when I found it would not pull over a 5 KW load I found the problem with the governor linkage which has probably helped as much as the fresh starter and the injectors put together. It still does not start as quick as I would like, and takes a fair amount of cranking, but each step keeps getting it closer to right. Now it starts well enojugh that I will probably have to wait for next winter to continue the trouble shooting

Ike

 

[rustystud]

Check the oil pressure switch. You have been running this unit for a long time now and this switch can get plugged especially if your oil is not the best. Bypass the switch, if it runs, change your oil and get a new switch.

 

[Keith_J]

And the low oil pressure safety switch can easily be tested. 1/8 pipe threads, hook it up to the output of an adjustable air pressure regulator. Then hook an ohmmeter to the two connections and slowly raise pressure while looking at continuity on the meter. Should be 12 to 15 PSI when it makes connection.

002 and 003s make white smoke on startup. That is normal. They also have a starter lockout which is centrifugal in operation, this allows the start switch to be held once up to speed, the starter should have long cut out. This is for both oil pressure cutout and field flashing.

Always observe the oil pressure gauge on startup, shutting it down if 15 PSI isn't reached once the white smoke turns black. There is a check valve in the oil system that can stick, causing loss of prime.

 

[Isaac-1]

White smoke on start up is relative, my MEP-002a gives a couple of puffs of white smoke on start up if it is cold out then clears right up in under 10-15 seconds. By contrast before replacing 2 of the injectors and getting the governor set right my MEP-003a would cloud up a 50 ft radius in white smoke before it cleared up after running for 2 or 3 minutes, it still smokes some (much more than the MEP-002a), but no one is going to mistake it for a brush fire now..