MEP-002A fuel system problem

[faraday]

Hi All,
I just took a chance and bought a 1983 MEP-002A. From what I have gathered on the web I think the engine is an Onan, but I don't know what model number.

Here is what I know about the Genset:
1. Has been sitting outside in all sorts of bad weather for last 10 years.
2. I put fresh diesel in and flushed most of the bad stuff out by disconnecting the hose after the filters.
3. Engine turns over and fuel is pumped as far as the injector pump.
4. Loosened 2 high pressure fittings on output of injector pump and nothing comes out. No fuel is making it to injectors.
5. The solenoid pulls up when cranking.
6. The linkage on the injector pump was/is somewhat stiff.
7. Tried moving the linkage to various positions while cranking but still no fuel out of injector pump.

Any ideas on this would be greatly appreciated. Also, the fellow has another unit that he has stolen the fuel pumps out of. He doesn't know what it's history is. Would it be worth buying for $100?

Thanks,

Henry

[Skytruck]

I have found that you have to have the linkage in the "full" open position to get the fuel flowing through the pump and out to the injectors. This would mean that the "some what stiff" lever would be in the uppermost position.

IMHO 100.00 for a second unit is well worth it. Scrap steel is about $390.00 a ton.

[faraday]

I tried cleaning the linkages around the injector pump, and manually forced the linkage under the solenoid to the up position, but still nothing out of the injector pump.

[BTPost]

I suspect that you will have to have the Injection Pump rebuilt, and timed.
Most "Good" Injection Pump Shops, will have all the parts, and a Flow Bench,
to do the rebuild and setup.

[Raymond]

Probably has a frozen/stuck pump plunger. Get the manual and take it apart and fix it. The MEP002 is a DJE (70 cu.in) or an over bored (no pun) DJB but uses the older distributor type pump and an even fire crankshaft. Its all 24 volt and the controls are all opposite the civilian Onans. I had one. One of the greatest ever built. You may find the noise excessive. Mine would do 7 KW all day and pick up a 2 ton a/c with 4 KW on it.

[Skytruck]

If you attempt to tear it down, go to the Ambac home page and look up their service bulletins section. they have great pdf files on the break down and service of the unit. http://www.ambac.net/

[faraday]

Thanks for the good ideas so far.

I talked with a old mechanic who works for a firm that a few years ago sold lots of these. He was familiar with the "stuck" injection pump problem. His solution, which worked for him on several occasions, was to disconnect everything from the input except the 6" hose and use it to fill the pump with lacquer thinner. He'd also crack the return line enough for the thinner to flow clear through the pump, then leave it filled for a couple of days.

He claims the pump doesn't have seals that would be affected by this. Anyone know if this is this true?

I wouldn't recommend lacquer thinner for an engine I cared a lot about, but this unit didn't cost me much so I can afford to experiment.

[Wayne 440]

The above describes nearly what my recently purchased set does, with the exception of the "stiff" IP linkage. Fuel, fuel everywhere until the injector lines. It had about a 1/2 ounce of water in the oil sump, but I haven't found a drop anywhere in the fuel system (so far).

At least I know the manifold heater works, after burning my $%^* hand on the intake.

[Wayne 440]

Originally Posted by faraday

...old mechanic...thinner...He claims the pump doesn't have seals that would be affected by this. Anyone know if this is this true?...

NOT TRUE...anyone have a good pump?

don't ask...

[faraday]

I checked with an injector rebuilding company and they said that lacquer thinner is a no-no. I sold the generator. New buyer was told that thinner was used. He seems to be up to the job though and will probably have the injector rebuilt.

[Wayne 440]

FWIW, putting thinner in an otherwise good, but "stuck" pump will result in a bill of around $200 to fix it properly. Now to see if my set runs.

[peyton]

Originally Posted by Skytruck

If you attempt to tear it down, go to the Ambac home page and look up their service bulletins section. they have great pdf files on the break down and service of the unit. http://www.ambac.net/

Thanks for the link Skytruck. Is the model 50 is the correct injection pump for the mep002a/003a? Sure looks the same. Thanks

Peyton

[Wayne 440]

The injector shop says my MEP002A pump is a model 50. Of course, it still doesn't run after they worked on it either....

[hurst01]

What happened to this thread? It just kind of fizzled out. This sounds like what mine is doing. It won't pump fuel. I will be disassembling the injector pump this evening to see if it can be done something with. I still wish I could find a seal/rebuild kit for it.
I guess you found out the hard way what lacquer thinner will do to "O" rings and seals. I will try to clean mine but with something less harsh. When I first tried to start mine I drained about 1/2 cup of a 9oz paper cup of water from the canister closest to the injector pump.
Skystruck, Thanks for posting the Ambec site. I was able to find a complete dis-assembly/assembly instructions on it for the injector pump. This should help greatly. I will post my findings, I may not get it done today.

Ed

[Wayne 440]

Well "what happened" to mine is I spent right at $200 on my pump, which still didn't work. The (so called) injection pump shop went out of business about 3 days after I picked my pump up.

The plunger in mine appears to be partly stuck, the tappet in the center of the pump gear is pushed down flush with the gear, but moves a little bit with finger pressure. It has been soaking in a can of clean fuel for about 3 months now.

I talked to another generator tech Friday that recommended the thinner "trick", but said a couple of hours was long enough. I'm just about tired of fooling with it...

[hurst01]

Wayne,
I finally got my injector pump apart this evening. I have to do it as I feel like it. I just recently got out of the hospital from having my third open heart surgery and this one is a bit harder to get up and going from.
Since this is the first pump I have taken apart, being unfamiliar with it I took my time. My plunger was stuck and the guide for the plunger was cracked. I may have done that though trying to get it apart the way the manual says.
I just sent a parts inquiry for a gasket kit and a new plunger guide to AMBAC. Another place told me that the pump and the parts for it had been discontinued.
After seeing what the inside is, I don't think lacquer thinner or soaking it will help. Think about it....... diesel fuel is a lubricant. it it stuck submerged in diesel, soaking it in something is not going to help.
After I find out about the availability of the parts I can have mine back together pretty quick. Soaking it in lacquer will probably ruin the "O" ring on the "tappet". If you want to PM me your phone number I can talk you through dis-assembly of the pump so that you can free the plunger. I tried going through the procedure that the manual says and I could not do it because it requires a special tool. I found another way to go in through the back door so to speak that is much easier without the tool.
Don't give up on it. If you don't feel like you can do it you can send it to me and I will free it up and send it back as long as you pay the shipping. These pumps are a lot more simple that I anticipated. I am going back together with the same buttons so I won't have to worry about changing clearances and changing the timing.

I see you are in KY. What part? Anywhere close to Louisville?

Ed

[Wayne 440]

It RUNS (thanks to hurst01). My youngest son got the now properly repaired pump back on, and it started fairly easily. After a little "adjustment" to the governor linkage and spring, the engine runs fine and stays right at 60hz. The longer it runs the better it sounds, and the exhaust is clear once up to operating temperature.

Now I'm going to read the "voltage regulator" threads, the "120/240" voltage is 157/314.