MEP-803A: It Runs, It Generates, but it won’t shut off

[Billy2642]

So I bought this 803a as a non runner with 1000 hours on it. I had it delivered with about 25 other machines and it did not have the exhaust flap on it which subsequently got water down the exhaust and ending up in the crankcase mixing water with the oil. I drained all that out and added fresh oil. In my mind I knew I should have pulled the heads and looked at the cylinders before turning it over buuuuuut, in the essence of time I didn’t and I got the machine cheap enough that if it just became a parts machine then it is what it is.

Anyway, I cranked the machine with the dead crank to cycle the oil and “rinse” it and then drained that oil and added fresh. Tried to start the machine but of course it would not start. No fuel getting thru the injector pumps. I tear those apart, clean, install, finally get everything bled (that took forever) and it started!!! Problem is, now it won’t shut off. When I turn the S1 off, the fuel actuator works as it should cutting fuel, the fuel pump stops running as it should, but the engine keeps running at seemingly the same 1800ish RPM that it was when everything was on. In fact. I don’t hear a change in the engine pitch at all when I turn the S1 off. It doesn’t smoke crazy bad as if the engine is “running away” but I can’t think of why it would still run if it’s not burning the crank case oil but fuel isn’t pumping either. This sounds completely dumb as I type this but any ideas? Is the engine in fact “running away” on the crank case oil even though it’s not smoking super bad and the smoke that is coming out is black and not blue? Can it still pull residual fuel even without the pump running?

To kill the engine, I had to take the air intake hose off and place a block of wood over the intake throat to choke it out

It starts right back up no problem whether I start it normally or use the dead crank switch. Never had a machine do this before. Ideas? I’m thinking it’s running off oil…..

 

[m32825]

https://www.steelsoldiers.com/threads/too-much-of-a-good-thing-mep-803a-wouldnt-stop.170466/

 

[Billy2642]

https://www.steelsoldiers.com/threads/too-much-of-a-good-thing-mep-803a-wouldnt-stop.170466/

I did read that thread prior to post my issue. The fuel solenoid, linkage, and rack appear to be working as they should. When starting the machine, the solenoid it actuating to open the fuel rack/pumps and when the S1 star switch is turned off, the solenoid returns the lever back closed butthr machine continues to run. Does not appear to be a linkage or actuator issue.

 

[nextalcupfan]

Is it possible when you reinstalled the pumps you rotated them to far in the "more fuel" direction?
I would try rotating the pumps first.
I've also heard it can be tricky to get the pump arms back in the rack properly, does the governor respond properly when you add load to the unit?
I admit this last one seems unlikely but might be worth a check.

 

[Ray70]

Have you load tested the machine yet?
It definitely sounds like either the internal rack is not moving correctly ( unlikely due to the way the linkage works )
Or the pump pins are either not in the rack's slots correctly, or not adjusted correctly.
Are the fuel inlet lines on all your pumps turned so they are almost touching the pushrod tubes? If they are too far away from the tubes, that puts the adjustment off to where the linkage is full off but the pumps are still open slightly.
I would think it would react differently under a load, but either way I would start by looking at pump positions!

 

[Billy2642]

Have you load tested the machine yet?
It definitely sounds like either the internal rack is not moving correctly ( unlikely due to the way the linkage works )
Or the pump pins are either not in the rack's slots correctly, or not adjusted correctly.
Are the fuel inlet lines on all your pumps turned so they are almost touching the pushrod tubes? If they are too far away from the tubes, that puts the adjustment off to where the linkage is full off but the pumps are still open slightly.
I would think it would react differently under a load, but either way I would start by looking at pump positions!

I have not load tested the machine yet. I will double check the positioning on the lines this evening and report back

 

[Billy2642]

Some Progress!

not entirely fixed but I did make some progress this evening before it got dark. I started with one of the suggestions above by adjusting the pumps. I rotated them all to where the pump inlet was as far towards the pushrod jugs as possible. I then started the machine and let it run for a minute but when I turned the S1 switch to off, it still did not turn the machine off. I again had to smother the intake. I then started the machine again and played with the frequency/rpm adjustment and it DOES respond when adjusted. I then turned the S1 off which of course the machine stayed running. I then took a ball peen hammer and lightly tapped right below the fuel cutoff ear/linkage and sure enough, it slowly idled down and cut off. I then adjust the stop all the way down for the ear/linkage thinking maybeit wasn’t letting it travel far enough. Started the machine again and rotated the S1 switch and still stayed running. I then tapped on it again and it slowly shut off. I did this a few times at various intervals just to make sure it wasn’t a coincidence with tapping on it.

Basically what I feel the issue is now is the fuel rack spring is either not strong enough to pull the rack back or it’s sticking for some reason. I’m pretty confident that I have the pins of each injector pump in the rack properly.I’m wondering if the rack is a little rusty inside from having the water in the crankcase. Question is, how do I free this rack up to work properly?

 

[jmenende]

If/when you removed the fuel pumps, always leave one installed. This leaves the rack in the correct position and makes them easier to reinstall. If you took all 4 out then you may find it easier to put a bore cam to see the slots align and then put in the pumps.

 

[Billy2642]

If/when you removed the fuel pumps, always leave one installed. This leaves the rack in the correct position and makes them easier to reinstall. If you took all 4 out then you may find it easier to put a bore cam to see the slots align and then put in the pumps.

I only removed 2 at a time just for this reason. Had that issue before and learned my lesson lol

 

[Light in the Dark]

The concern about metering pump reinstallation is overblown. If you see the indents in the fuel rack which tie to each pump, you can articulate the rack open to feel the locating points for each pump, to reinstall one. The rest drop in after that doing the same thing.

See the notches? Thats what you are lining up.

 

[Ray70]

I think you may have a slightly different issue with the governor / rack assembly. Your prognosis is good, but if I recall, the springs on the rack only provide OPENING force. To close down the fuel pumps the connection is a lever without springs. Look in the attached picture and my recollection is that #22 is rotated counterclockwise by the shut off lever #25. these 2 parts are held together by the slot / tab I have circled. I once had an LPW2 I bought for a spare that wouldn't shut down because when the mechanism was assembled, assumingly at the factory, the tab was not engaged with the slot, so it was not moving the rack properly. There was some friction there, but it would slip due to the misalignment of the tab. I reassembled it correctly and all was good.