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Mep-803a motor locking up at 0 and 180deg

A

Aaawolfe

New member
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Location
Louisiana
Hello all I’m new to the forum and new to mep generators. I picked one up last week from gp. Appeared to be in decent shape just over 700hrs, exhaust flap intact, everything there and complete except missing main fuel pump. Description on auction showed it wasn’t operable but would crank over (makes since with it missing fuel pump).

Couldn't turn the engine over by hand with engine fan but the belt was also loose and slipping. Ordered new filters fluids and fuel pump but haven’t received it yet. Got the batteries installed in it yesterday and decided to try and bump the engine over to make sure electrical system was functioning and that the motor turned over freely. Starter engaged but engine didn’t move was locked up.

Today i I pulled the injectors and filled the cylinders with atf fluid and mystery oil. Exhaust manifold didn’t have black soot in it had slight bit of rust but wasn’t heavily rusted up. Injectors had black soot on end of them and no rust. Tried to look in the injector ports looked mostly clean in there from what little bit I could see didn’t see any rust.

Put ratchet on crank pulley nut and got the engine to turn with very little resistance. Once got it started moving was able to turn it over with the fan by hand but I am hitting a hard stop in both left and right directions. It is binding up exactly 180 deg apart when turning it over and can’t get thru that hard spot. I am now suspecting thee is an issue in the bottom end of the engine seeing how easily it moves between these two hard stops. I plan to open the lower engine inspection port tomorrow to see what’s going on. Anyone else have experience with this or have any other recommendations? Any help would be appreciated.
 
A

Aaawolfe

New member
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Louisiana
Well good news I got it freed up but still not sure what was binding or why it freed up.

Pulled off the lower end cover and had a look up in the engine with a mirror and didn’t see any issues. Was able to see all the pistons moving up and down see all the connecting rod and the wrist pins together and in good shape. What I could see of the cylinder walls they were in good shape too. Saw two small patches of rust on the crankshaft but other than that every thing looked like new.

The engine was still binding up when the two inside pistons were in up most position with the two outside pistons in the down position. It would also bind up going the other way with the inside pistons down and the outside pistons in the upmost position. Couldn’t see anything binding it up down there.

I pulled the valve covers off and all the valves were moving freely. Pulled the rocker arms off two of the cylinders and tried to figure out which rods the cam shaft was engaging when the motor blinded in the two spots. Reached up in the motor with a Allen head wrench to try and move the popits manually and found one I couldn’t move freely. While turning the engine over by hand it went past one of the points where it binds at and completely locked up. Had to put a prybar on the flywheel to un bind it. After this I was able to move the engine thru this binding point just had more resistance and eventually all the resistance left after turning it several times.

Still was binding in the second spot from both directions and was a hard stop. I had marked the fly wheel where it was binding and wasn’t the exact same point from both directions was about an inch on the flywheel apart from each way. Removed rocker arms from the 3rd cylinder and eventually while moving the motor back and fourth it got thru the binding spot. Only thing I could think was binding up was the popits above the camshaft so I poured some oil down the lifting rod tubes.

It it is spinning freely from both directions now. Do you think still warrants opening up the cylinder heads to see if there is a deposit or buildup in there that was binding it up or is the popits binding up a likely issue? Also need recommendations on where to find a gasket kit for the engine to seal up the valve covers lower engine compartment door and the intake manifold.
 
R

robertsears1

Active member
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Near Apex/NC
I am pretty sure Guyfang means the dead crank switch inside the engine door on one side. When you finish, make sure and put it back to normal (or whatever means normal so that you can cank it from the control panel). Download the books and read about the starting sequence. These MEP generators are different than any other engine I have ever started in that you hold the switch in start after it is running, it will not hurt anything. If you count to 10 or 15 before you release it, that should work. The oil pressure should have stabilized and then the field must be flashed to excite the generator so that it will produce electricity, holding the switch will get that done if the set is working properly. Behind the control panel on this model I believe, is a switch that controls if it is producing single phase or three phase electricity. Never change this with the set running! If the above seems like I am writing in a foreign language, read the books! If you tell us your background, it will help us help you. You seem to know one end of a wrench from the other so that is a great start. These are not usually plug and play at the beginning.

Robert
 
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A

Aaawolfe

New member
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Location
Louisiana
So far I have only turned it over with the injectors out. I have got most of the fluid out (squirting out on me when I turn over the engine) but can still hear some moving around in there when I stroke the engine. Are you saying I should hit the dead crank switch with the injectors in or hit it with them out to blow any remaining fluid out?

I have read up quite a bit on these generators so am familiar with their normal operation however I didn’t plan on having to tear into it so haven’t read up as much on that aspect of the generator. I was looking at the tm last night on how to reinstall the rockers and didn’t know about having to let it set for 45 min to bleed down the lifters. The oil system hasn’t Ben ran for prolly several years so hopefully I didn’t bend any rods.

I have a good mechanical aptitude and am pretty handy around a wrench however I don’t have any experience working inside a motor only on outside of it on external components. I work in a manufacturing plant so have good problem solving skills that helps with troubleshooting. I must say working on this mep generator has been a pleasure it is old simple technology and is relatively easy to work around. Also the Tms provide pretty good direction when you are questioning something.
 
A

Aaawolfe

New member
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Location
Louisiana
We had our thanksgiving today once I woke up from my turkey coma I reinstalled the starter and batteries and wired it all back up then cranked the engine with injectors out and mainly just blew black mist out not many drops of fluid in it. Once done I reinstalled the injectors. I read the tm for installing injectors as I was coming out of the before mentioned coma and after reading the procedure I went to the figure to make sure I was on the injector hold down bolt to get the torque spec then went back to the procedure but got on the wrong one. Apparently got on the procedure before the one I was trying to and saw a torque of 58ftlb. Tried to torque the first injector to 58ftlb and snapped it offaua. I now see it is actually 15.5ftlbs.

I will be going to town tomorrow to buy an easy out and some more bolts. The tm doesn’t have any details of the bolt size. Anyone know the thread size and pitch? Also should it be grade3 or grade5 bolt?

While I’m waiting on my gasket kit to come in I would like to pull the oil pressure regulator out and clean it. Can someone explain to me how to do this and is there any adjustment that has to be made to it so it gives the correct pressure?
 
F

Farmitall

Well-known member
Steel Soldiers Supporter
544
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Location
Eubank, KY
I don't know the bolt size but for the minor difference in price, I'd go with a grade 8 bolt. Better hard than too soft in this case.
Hope your removal goes smooth.
 
C

Coug

Well-known member
Steel Soldiers Supporter
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Olympia/WA
most hardware stores have a bolt sizing display you can use to match up existing bolts pretty easy, so if you have one off another injector hold down just take it in with you.
If nothing else if there is anyone halfway competent at the store they should be able to match it for you.

As Farmitall said, rather have it harder/stronger than required than weaker if it isn't being used as a shear pin, so go grade 8.
 
A

Aaawolfe

New member
6
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Location
Louisiana
Hello all. Been busy here with holidays and work but have been able to get my mep-803 all put back together over the past few weeks. I have it cranking over smoothly but am not getting any fuel to the injectors. New electric fuel pump and filters and fresh diesel. I bled air off the 2nd fuel filter per tm’s and can hear fuel recirculating into the fuel tank. I have cracked the fuel lines on top the the mechanical fuel pumps but am not getting anything coming out. I tried to back the fitting off on the mechanical fuel pump 1/4 turn but they are all on there tight and just results in the whole fuel pump trying to spin. I completely removed the fuel lines off of the mechanical fuel pumps and am not getting any pumping action when cranking the engine over.

I pulled one of the fuel pumps out and inspected it and looks to be in good condition and I can push the plunger spring and it moves freely. I used a mirror and can see the slotted arm the little switch on the fuel pump rides in however when I manually stroke the fuel cutoff arm I am not seeing the slotted arm move. I am assuming this is supposed to move and is preventing fuel from going into the fuel pump. Is this a common issue and I am assuming i need to open up the front cover on the engine to fix it. Any advice would be appreciated.

Also on a side note I can crank over the engine with the battle short off but when I turn it on the engine doesn’t crank. I can hear a solenoid click behind the control panel but starter doesn’t engage and turn over. I checked continuity on the battleshort switch per the tm’s and it checks out and when the switch is supposed to be off it is actually off so not like the switch has rotated upside down. Don’t think this is related to my above fuel issue but thought I would put it out there as once I get the generator running this will be next thing I try to troubleshoot.
 
J

jamawieb

Well-known member
1,437
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Location
Ripley/TN
Aaawolfe said:
Hello all. Been busy here with holidays and work but have been able to get my mep-803 all put back together over the past few weeks. I have it cranking over smoothly but am not getting any fuel to the injectors. New electric fuel pump and filters and fresh diesel. I bled air off the 2nd fuel filter per tm’s and can hear fuel recirculating into the fuel tank. I have cracked the fuel lines on top the the mechanical fuel pumps but am not getting anything coming out. I tried to back the fitting off on the mechanical fuel pump 1/4 turn but they are all on there tight and just results in the whole fuel pump trying to spin. I completely removed the fuel lines off of the mechanical fuel pumps and am not getting any pumping action when cranking the engine over.

I pulled one of the fuel pumps out and inspected it and looks to be in good condition and I can push the plunger spring and it moves freely. I used a mirror and can see the slotted arm the little switch on the fuel pump rides in however when I manually stroke the fuel cutoff arm I am not seeing the slotted arm move. I am assuming this is supposed to move and is preventing fuel from going into the fuel pump. Is this a common issue and I am assuming i need to open up the front cover on the engine to fix it. Any advice would be appreciated.

Also on a side note I can crank over the engine with the battle short off but when I turn it on the engine doesn’t crank. I can hear a solenoid click behind the control panel but starter doesn’t engage and turn over. I checked continuity on the battleshort switch per the tm’s and it checks out and when the switch is supposed to be off it is actually off so not like the switch has rotated upside down. Don’t think this is related to my above fuel issue but thought I would put it out there as once I get the generator running this will be next thing I try to troubleshoot.
Click to expand...
With the fuel rack, it only takes a little resistance and it won't move. Stick you finger into the hole where the pump came out and manually move the fuel rack towards the generator head, to see if it will move. It moves based on springs so it's not directly attached to the shut off solenoid lever, this is why very little resistance will make it not move. I take the pumps apart while they are still mounted in the engine, then use a mirror to look down into the pumps to see the plunger move left to right with movement of the fuel cut off solenoid and movement up and down with the motor cranking over. Its a pain to get the pumps back into the fuel rack when you pull them out. With it not moving, will cause no start because its not allowing the pumps to open for fuel.

Like Guy said, it should not start with the battle short on.
 
A

Aaawolfe

New member
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Location
Louisiana
I pulled the #2 fuel pump out and it appears to be the culprit. The lever is seized up on it and the piston is stuck in the up position. With it pulled out the fuel rack is now moving when I stroke the fuel cutoff switch. Couldn’t get the piston or the lever to move after spraying it down from the outside liberally with pb blaster. I took the fuel pump inside to my vice to try and lock it down to pull the fuel exit fitting on top of the pump so I can inspect the inside of the pump but can’t get the nut broke loose. Are the threads by chance left hand? I’m afraid to pull any harder on it scared may damage it or break the threads. I put it in a cup of atf fluid to soak overnight hoping it will free up so I can open the pump. Any other pointers on how to get it opened up?

How do I pull the fuel pump piston out Incase I can’t get it freed up and stroking with lube? Don’t see any info on this in the tm.
 
U

uniquify

Active member
228
223
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Location
Sioux Falls, SD
Similar thing happened to me earlier this year. The #2 injection pump stuck in the up position and wouldn't let the fuel rack move. I took the top of the pump off and tried filling it with carb cleaner and letting it soak overnight. After doing that off and on for a couple weeks with no change, I doubled down and pulled the pump off. Once that pump was off, the rack was able to move again -- that confirmed to me that I only had 1 pump stuck and this was the culprit.

To get the pump working, I ended up using a brass punch to tap the plunger down. After a couple light taps, it unstuck and the bottom spring pulled the plunger the rest of the way down. Then I used more carb cleaner and a bottle brush to clean things up inside. It took a while of working the fuel lever side to side before everything felt good again. Once it was moving well, I reassembled the pieces and put the pump back in, primed all of the fuel lines, and it fired right up.
 
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