MEP-003a fuel issue

[MuddFlapp]

clean fuel is a must. clean and new fuel so change it every 6 months. it must be clear, otherwise this and worse happens. just finished my second drive key R&R on a 003A.

New fuel and flushed lines, new filters.

 

[John Sowden]

Doesn't this come in the rebuild kit KT85166 ?

 

[Zed254]

This is a VERY old thread........From the big auction site......GMG at around $99....hope you can find another vendor.

Ambac M50 Fuel Injection Pump Gasket Rebuild Kit for 50-2/4A-80A-9540A, KT85166, Onan 147-0308

Ambac M50 Fuel Injection Pump gasket rebuild kit for the injection pump used on MEP002A and MEP003A generators as well as many other machines. The Ambac pump number is: 50-2/4A-80A-9540A. This kit includes the following:

• GA401310 - Copper Gasket
• SR8515 - Spacer
• GA100282 - O-ring Gasket
• GA403385 - O-ring Gasket
• GA407743 - Gasket (Onan 147-0247)
• GA1146 - Gasket
• GA402929 - Copper Gasket

Brand: Ambac
MPN: KT85166
NSN: 5330003406374
Other Product Numbers:
SKU: 1217
Categories: Generator and Engine Parts
Tags: Ambac M-50-2/4A-80A-9540A Parts, MEP002A Generators and Parts, MEP003A Generators and Parts

 

[Buttweet]

These pumps, m50's, are so troublesome. Once they are disassembled, good luck making them work again. Just bought a rebuilt one on eBay for $350, can't make it work no matter what I try. Also, on my other mep003a, someway, engine oil is getting inside the pump and it will start but smokes like crazy for 5 minutes then engine dies. Need help bad. Any ideas?
Frustrated and discusted.....thx

 

[Light in the Dark]

Can you clarify what you have done to make them work? Maybe its a process error, and not a part concern.

 

[Buttweet]

Mep003a injector pump low pressure problem

Can you clarify what you have done to make them work? Maybe its a process error, and not a part concern.

First with the smoking mep003a, injector pump has never been removed. Think it is ok as far as starting is conserned. For some reason smoke boils out both exhaust when it starts. Like engine oil is entering pump mixing with the diesel. May be a gasket deterioration inside the pump.
Second mep003a, it set for a month and plunger seized and the bow tie sheared when tried to start it. Plunger was seized so tight it could not be rotated. I destroyed the pump trying to free it up. So I ordered a so called rebuilt pump from eBay. Ad said it had a button, but it did not. I installed a no. 13 button I had on hand just to get it started. Before installation, I set the flywheel on TDC with the cam lobe pointing 45degrees down per instructions and inserted a 1/8 inch drill in the pump flange hole. Connected the fuel supply lines, but left the injector lines off so I could monitor the fuel squirting out of the the 4 outlets of the injector pump. When turning the engine over instead of fuel squirting out, it was just dribbling out. Yes, the prime pumps are working full blast. This rebuilt pump was rebuilt, according to a copy of an invoice, 8 years ago by a diesel company in Ohio. The seller has agreed to take it back. I've lost all confidence in rebuilding these pumps. A rebuild kit ($80) consists of just 2 or 3 gaskets and that many orings. I have totally disassembled 2 or 3 of these pumps, rebuilt them and they never work. New ones are $700+. Sorry to bore you with the clarification, but that's the rest of the story. Any suggestions? Thanks for listening.

 

[jamawieb]

On the first pump, its not the pump causing the oil build up. 99% when you have excessive smoke and oil substance coming out the exhaust, its going to be the injectors. They are leaking into the cylinder. There is only one large gasket between the head and pump body, the plunger is the only thing between the pump head and the gear face.

Okay, they are kind of hard to dial in. When testing for the correct button, you will have to remove the delivery spring and then have the throttle open to the fully open position. Then back the blower, counter clockwise 15 degrees, start pumps, and then rotate clockwise until the injector pump stops. It should be at the PC mark on the flywheel.

I remember the first time I dealt with the pumps, I felt the same way. I bet it took 4 hours to put a pump on and dial it in, now it takes about 45 minutes.

 

[Buttweet]

Thanks for your assistance. I'm trying to understand what you are saying. Injectors leaking diesel fuel into the cylinders while the engine is not running? And the diesel fuel leaking past the piston rings into the crankcase which raises the oil level in the crankcase, which I should notice on the dipstick? Is that what you are saying? I will check the oil level. This happened to me on my AllisChamers tractor. As a result the crankcase was several quarts too full of a mixture of engine oil and diesel fuel. But the diesel was leaking thru a damaged seal in the IP and into the crankcase overnight. And the solution on my genset would be to pull the injectors for a pressure test?

On my second genset, I'm only getting minuscule flow out of the rebuilt IP I purchased from eBay. I know the timing is in the ballpark and the no.13 button should produce enough flow to at least see some gray smoke out the exhaust when trying to start the engine. But nothing. I'm convinced the pump is just not producing sufficient pressure even though the timing and button are not perfect. I did the flow procedure per instructions for dialing in the timing and got substantial flow out of each outlet, which tells me the dog bone or bow tie is not sheared. But that has nothing to do with the IP pressure producing capability when running or trying to start running. So, bottom line, I think the pump is defective.
Do you agree? I appreciate your time and wisdom on these IP's. Anyway, I'm returning the rebuilt pump to the eBay seller and looking for another pump that has been pressure tested. Thanks

 

[Guyfang]

Thanks for your assistance. I'm trying to understand what you are saying. Injectors leaking diesel fuel into the cylinders while the engine is not running? And the diesel fuel leaking past the piston rings into the crankcase which raises the oil level in the crankcase, which I should notice on the dipstick? Is that what you are saying? I will check the oil level. This happened to me on my AllisChamers tractor. As a result the crankcase was several quarts too full of a mixture of engine oil and diesel fuel. But the diesel was leaking thru a damaged seal in the IP and into the crankcase overnight. And the solution on my genset would be to pull the injectors for a pressure test?

On my second genset, I'm only getting minuscule flow out of the rebuilt IP I purchased from eBay. I know the timing is in the ballpark and the no.13 button should produce enough flow to at least see some gray smoke out the exhaust when trying to start the engine. But nothing. I'm convinced the pump is just not producing sufficient pressure even though the timing and button are not perfect. I did the flow procedure per instructions for dialing in the timing and got substantial flow out of each outlet, which tells me the dog bone or bow tie is not sheared. But that has nothing to do with the IP pressure producing capability when running or trying to start running. So, bottom line, I think the pump is defective.
Do you agree? I appreciate your time and wisdom on these IP's. Anyway, I'm returning the rebuilt pump to the eBay seller and looking for another pump that has been pressure tested. Thanks

this for the second set. Every time this happened to me, I removed the lines from the pump. Timed the engine. Pulled the pump out, rotated it 365 degrees, and put it back in. It even says in the -34 TM, that if the gen set will not start upon replacement of pump, to do this. Don't forget, not only does the engine need timing, but the pump also.

 

[gimpyrobb]

this for the second set. Every time this happened to me, I removed the lines from the pump. Timed the engine. Pulled the pump out, rotated it 365 degrees, and put it back in. It even says in the -34 TM, that if the gen set will not start upon replacement of pump, to do this. Don't forget, not only does the engine need timing, but the pump also.

365 or 180?

 

[Guyfang]

Gimp,

your right, 180. My head is still cloudy from the drugs they gave me for my OP. Thanks for keeping me straight!!

 

[jamawieb]

Thanks for your assistance. I'm trying to understand what you are saying. Injectors leaking diesel fuel into the cylinders while the engine is not running? And the diesel fuel leaking past the piston rings into the crankcase which raises the oil level in the crankcase, which I should notice on the dipstick? Is that what you are saying? I will check the oil level. This happened to me on my AllisChamers tractor. As a result the crankcase was several quarts too full of a mixture of engine oil and diesel fuel. But the diesel was leaking thru a damaged seal in the IP and into the crankcase overnight. And the solution on my genset would be to pull the injectors for a pressure test?

On my second genset, I'm only getting minuscule flow out of the rebuilt IP I purchased from eBay. I know the timing is in the ballpark and the no.13 button should produce enough flow to at least see some gray smoke out the exhaust when trying to start the engine. But nothing. I'm convinced the pump is just not producing sufficient pressure even though the timing and button are not perfect. I did the flow procedure per instructions for dialing in the timing and got substantial flow out of each outlet, which tells me the dog bone or bow tie is not sheared. But that has nothing to do with the IP pressure producing capability when running or trying to start running. So, bottom line, I think the pump is defective.
Do you agree? I appreciate your time and wisdom on these IP's. Anyway, I'm returning the rebuilt pump to the eBay seller and looking for another pump that has been pressure tested. Thanks

On the first unit, I would say the injectors are leaking while they engine is running. Instead of closing completely after the combustion stroke, they are continuing to leak into the cylinder. More than likely it won't leak enough to get into the oil but its enough to saturate the cylinders where it can't burn it off.

On the second unit, anytime you put a new pump on you have to flow test to make sure the button is correct. The injector pump housings and engine block thickness is different on every unit so the button is very important for the operation. You wouldn't believe the problems that happen with a .010mm difference in thickness.

Also on the timing its a lot easier to take the valve cover off closet to the blower to see the intake valve close then look for A on the flywheel. Guy is correct, if the pump is 180 off you won't get anything out. When it's 180 off the plunger won't be at the point to get fuel into it to send out to the injectors.

 

[Buttweet]

Thanks for the response Jamaweib. I did as you said and found A on the flywheel. Is this the flywheel position where I mount the pump? I had thought the cam lobe had to be pointing down 45 degrees when mounting the pump but I was probably wrong. I will try it again.
Thanks
JR

 

[jamawieb]

Thanks for the response Jamaweib. I did as you said and found A on the flywheel. Is this the flywheel position where I mount the pump? I had thought the cam lobe had to be pointing down 45 degrees when mounting the pump but I was probably wrong. I will try it again.
Thanks
JR

I'm sorry, do the same thing but look for PC on the flywheel, its right before A, that is where the pump should be installed. I had a brain fart this morning and was thinking of the valve timing.

 

[Buttweet]

What is the purpose of the "A" Mark on the flywheel? Thx

 

[jamawieb]

There is A and B on the flywheel along with PC. A and B are for checking the clearance between the rocker and valve. Your supposed to do this every 500 hours 'I believe' from the TM. I usually do 1000 hour intervals.
When you get to the combustion stroke of cylinder one, you would turn the flywheel until you reach A. Then you would check the valve clearances. Exhaust is .007 and intake is .010 if memory serves me. Then you go to B for cylinder 2.

 

[Buttweet]

OK....question: my pump that I'm trying to install has a no. 12 stamped on its flange. If I use a no. 13 button and install it on PC and with a 1/8 rod in the flange hole, it should at least crank up, right? I only have one button.

 

[jamawieb]

OK....question: my pump that I'm trying to install has a no. 12 stamped on its flange. If I use a no. 13 button and install it on PC and with a 1/8 rod in the flange hole, it should at least crank up, right? I only have one button.

Maybe, its hard to say. It may be stamped with 12 because that was the match on the engine it came from. If it was me, I would do the flow test as soon as you put the new pump on. Take the big cap off the center of the head, it's like a 7/8, then use a 16mm to take the delivery spring holder out that is below the cap. There is a spring in there and you need to remove it, then put holder and cap back on. Stick a large screw driver under the throttle so it will be a wide open throttle. Start with the flywheel at the PC mark after the combustion stroke of the number 1 cylinder.Turn the blower counter clockwise about 15 degrees from the PC mark, then turn the master switch to prime/run and you should have diesel spraying out of the number 1 port in the injector pump. Then turn the blower clockwise until the diesel stops. When it stops look at the flywheel and it should be on the PC mark. If its not then we will have to take measurements to see what button you will need. The housings and engine block thickness is different on every engine so you may have problems.

 

[Buttweet]

Thanks for the response Mr Jamawieb, You are such a patient, helpful person teaching me how to install this pump. I did the flow test as you described and I think I got some good info this time. The flow stopped at 1 1/4 TDC marks below PC. Or .200+.050 inches below PC which indicates late timing. The button I used is a no. 13. Looking at the button chart, I need a no. 15 or 16 button, probably closer to a 15. Can you recommend a button source. Prices I've seen are all over the map for these buttons. Thank you so much. JR

 

[jamawieb]

Your welcome, that is what we are here for.
I believe your right, from your measurement I come up with .187mm late. So your button 13 is 3.17 + .187 = 3.357mm. Button 15 is 3.33mm I agree with button 15. I see one on ebay for $25 with free shipping. The other place surplusgarage is $24.19+ shipping. I'm not sure how much they are from Ambac.