MEP-002a injection pump replacement?

[Isaac-1]

Well when it rains it pours, literally, we have a Cat 4 Hurricane on the way scheduled to be here in the overnight hours, and now my MEP-002a will not start. It ran fine when I last started it a few months ago, now it is not getting fuel to the injector pump. I have a spare new in the box injector pump I bought about 7-8 years ago, so I have that going for me, I just hope the current timing button will be the right size, if not I have 2 other scrap Onan DJ series engines to scavenge from.

My issue is the marking on the new injector pump, the number stamped into right edge of the lip of the pump reads "14" which I have no idea how to use to calculate button size, any thoughts?

 

[Chris454]

ARE YOU 100 %SURE THE IP IS BAD. I RAN INTO THIS EXACT SCENARIO A FEW MOTHS A GO AND IT TURNED TO BE A BLACK PLASTIC BALL SOCKET ON THE SIDE OF THE IP HAD BROKEN CAUSING THE LINKAGE NOT TO MOVE. UNFORTUNATELY I TOOK A LOT APART BEFORE I REALIZED THAT.

 

[Isaac-1]

I will double check before pulling it apart, but I am getting fuel to the injector pump and nothing coming out of it.

 

[Chainbreaker]

Welcome Back Isaac-1, been a while since you have been active in the Generator forums.

Do you hear any fuel returning to the fuel tank via return hose?

Also, might try putting in some Seafoam or Carb Cleaner in last fuel filter cannister and seeing if that might trickle through the fuel pump and free up any gum/blockage.

BTW, I was watching the Weather Channel this morning and was extremely surprised to hear that Hurricane Laura had increased by 65 MPH overnight to a 140 MPH Cat 4 hurricane. Expecting a 15-20' storm surge in Lake Charles area with I-10 predicted to be under water in areas! Stay Safe!!!

In the meantime, I will look up what the number relates to that is stamped on side of your spare pump. Coincidentally, today I saw a diagram with those stampings on the Ambac M-50 pump

 

[Chainbreaker]

OK, here is a link on how to select the correct Timing Button should you do decide to replace the pump.

 

[Chainbreaker]

Here is a recent post that MIGHT be relevant that could help you troubleshoot your injection pump:

Courtesy of a recent Jamawieb posting in another thread:

" After you get the fuel system cleaned, try to move the throttle linkage on the injector pump up, I'm betting its not going to move. The plunger inside the pump always gets gummed up and if its at the lowest position when starting, it will break the plunger guide. Then you have to disassemble the pump to replace the guide. I always fill the last fuel filter canister with acetone or carb cleaner, then turn the fuel pumps on. As the fuel starts mixing with the acetone start rotating the engine over by hand while moving the throttle linkage up and down. You can also take the large nut off (in between the hard fuel lines), then remove the cap, spring, and other pieces to gain a view of the top of the plunger, then rotate the motor over by hand and see if the plunger moves in and out (if it moves in and out you're good). You can use a brass punch to hit the plunger if its stuck in the high position, to move it. Worse case, you may have to pull the pump off to clean it. "

 

[Isaac-1]

Thanks, I have already seen that, just don't have a clue how to interprit "14" stamped in to the right flange, is that mm inches, etc?

p.s. trying to get done boarding up doors, etc to get out to check the linkage for movement

 

[Chainbreaker]

It gives an example in both inches & mm on page 4 paragraph 3. of that PDF. By comparison you should be able to interpret if its specified in inches or metric given those parameters in example.

 

[Isaac-1]

I just went out and had my wife crank the MEP-002a while I watched the plunger, the solenoid lifts up while cranking, but the arm on the side of the injector pump does not move.

 

[Chainbreaker]

Try suggestions in my post #6 above. /\

 

[Isaac-1]

Will do, but it will have to wait until the storm passes, it is starting to get breeze here, though not too bad yet.

 

[Chainbreaker]

I just went out and had my wife crank the MEP-002a while I watched the plunger, the solenoid lifts up while cranking, but the arm on the side of the injector pump does not move.

You should be able to move the linkage IP arm freely even without cranking. If you have any type of cleaner: carb cleaner, seafoam, acetone, etc. and could fill last filter cannister with it and let fuel pumps circulate it for a few minutes and let it sit overnight it just might free up the inner workings of your injection pump assuming it's gummed up.

Understand though that you have more pressing issues at hand so do what you need to do 1st to remain safe!

 

[Isaac-1]

The best thing I have on hand is probably ATF fluid

 

[Ray70]

In addition to the pump lever possibly being sticky also check that the arm isn't rubbing on the hole in the sheet metal where it passes through up into the top portion under the "Close to Run" cover. Have your wife crank it and see if you can give it a little help with your finger. If it's stuck bad you will have to go through the IP cleaning process, but maybe it will simply pop loose with a little guidance!