Diesel in my fuel injection pump

The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.

Vandeusen

Senior Member
Joined
Dec 14, 2021
Messages
208
When I purchased my trawler did not notice that I had a diesel leak when my RPMs were rubbed up pretty good until after I started taking my trip I noticed that wrong boat was put in on the side of the fuel injection pump where you would wait for the oil to come out to know that you had enough oil in it I also noticed that within a 10-hour sale I had dropped about a gallon of diesel in the oil catch pan onto the oil pads.

I drained everything cleaned it out real good bored out a new hole and put a new screw in along with Permatex my question is if diesel is going into the area where the oil is supposed to be on the fuel injection pump how bad of a thing is it? Second now that I sealed it up to where it's no longer going to be leaking out of the side of the injector pump into the oil pan area down below what do you guys think is going to happen if I start running the motor? Do you think I'm going to blow something somewhere or do you think the oil is going to keep the diesel where it should be and not let it come through? And if so am I better off replacing the fuel injection pump even though I know it's 2,800 bucks or just go ahead and try to send it to a rebuilt company? Thank you for any suggestions anybody can bring to this discussion
 
If you have a Lehman then you are dealing with a well known issue. Over time the diesel will enter and contaminate the oil. The rate at which this happens varies but the guideline is to drain and fill with fresh oil every 50-100 hours. Once you do this you can track and adjust your interval but I personally wouldn't go beyond 100 hours.

Diesel is not a horrible lubricant so hopefully no damage done. Change it and run 10-25 hours. If the oil level is rising then that is due to diesel. I wouldn't get it rebuilt until you know if it is excessively leaking. To me that would be based upon significant diesel in less than 25 hours. Otherwise just keep up with the scheduled change.
 
If you have a Lehman then you are dealing with a well known issue. Over time the diesel will enter and contaminate the oil. The rate at which this happens varies but the guideline is to drain and fill with fresh oil every 50-100 hours. Once you do this you can track and adjust your interval but I personally wouldn't go beyond 100 hours.

Diesel is not a horrible lubricant so hopefully no damage done. Change it and run 10-25 hours. If the oil level is rising then that is due to diesel. I wouldn't get it rebuilt until you know if it is excessively leaking. To me that would be based upon significant diesel in less than 25 hours. Otherwise just keep up with the scheduled change.


Over the course of a 10-hour trip I was dumping about a gallon of diesel out of that area of the fuel pump now that I sealed it all up what happens if the diesel makes it into the oil compartment and what happens if it raises the oil level thank you
 
I'd suggest you contact Brian at American Diesel. Some clear up close pictures would help. That is a lot of diesel to lose. These pumps do not last forever and any sign of large fuel loss as you have is a clue.

The usual answer is rebuild the injection pump, but if there is a crack in the pump body rebuild is not possible. The rebuild shop can answer the question.

Two years ago I had a small fuel weep addressed by rebuilding the pump. Yes the weep disappeared plus the engine ran much smoother. Point being, an external leak is often a clue as to the pump operation.
 
Can't say for sure, but if you "buy" an injection pump it may just be a remanufactured one.

Anyone know if they are still manufacturing new or have new off the shelf injection pumps for Lehmans?

I wouldn't be too sure there was diesel in the pump itself. Just because there was diesel all over the pump and a gallon in the pan doesn't mean it came from inside the pump. It is common for a little Diesel to enter the pump itself, but when that starts, you should be doing oil changes between 50-100 hours depending on just how much dilution is going on.

Leaks around the o rings that are where the injector fuel lines enter the pump and the lines themselves are leak prone. In my 10 years of ownership, I had 2 major pipe leaks and a weep from one fitting on top of the pump. But never any diesel inside the pump.

As far as starting up the engine...that's always a best guess. People have reported running their pumps with no oil at all (bottom plug missing after a run or two)....and others with a lot of diesel in the pump itself and had been run for a change interval of 50 hours.

Some tidbits here....

https://www.trawlerforum.com/forums/s6/minnimec-delivery-valve-seal-leak-lehman-120hp-21669.html
 
Last edited:
The engine ran kinda ugly because it had been sitting for over a year when I bored out the hole and put the new screw in the diesel stopped leaking there was a fresh oil change done to it and over the course of traveling from Kentucky to Mississippi minus the diesel that was leaking it ran fine when I put the new screw in it sounds one heck of a lot better than it did in the first place I will keep an eye on the oil, but if I see the oil starting to rise I well immediately turn off that motor and not use it again until the pump is rebuilt or replaced?


I do understand these engines can leak oil and Diesel but I don't see anywhere in the motor that the leak of the came from other than that spot we checked underpower, idling and you only lose diesel when your RPMs are up and then you still couldn't see where it was coming from but that breather hole screw was loose
 
Have you checked to see if the sump oil level is increasing, as it would if some of the leaking diesel is finding its way into the sump?

And perhaps you could post a picture of the plug hole where the diesel was leaking from, just to be certain it's the oil level check hole, and not something else? I'm not familiar with these engines or pumps, but others here know them well.

These things I think will help cross-check what's happening.
 
Have you checked to see if the sump oil level is increasing, as it would if some of the leaking diesel is finding its way into the sump?

And perhaps you could post a picture of the plug hole where the diesel was leaking from, just to be certain it's the oil level check hole, and not something else? I'm not familiar with these engines or pumps, but others here know them well.

These things I think will help cross-check what's happening.

No i ran it for a few minutes after I put the new screw in it is the oil leak check hole and how do I upload a picture on here? I do have pictures as well as YouTube video I will post that link here

https://youtu.be/Qg9fuP6uGug?si=kjScTNGfI4CXSD27

part 2 https://youtu.be/82wGahcPIhY?si=lAg8rnZ8c1YAUC8p

That is what i done so far...
 
Last edited:
Have you checked the engine oil level to see if diesel is getting in there. Never had this problem with Lehman but was aware of the lift pump failure which would leak into the oil sump as well as into the tray.
The amount of diesel found in you tray, if it came from the diesel injection pump through the oil level fill, then it needs an immediate rebuild or replacement.IMO

But then that is why I have two engines as you do.
 
I gallon diesel leaked is a bit more than 1.5 cups per hour.

That would be huge to have come from fuel leaking into the injection pump sump.

My quick guess is you had a stripped oil level check screw that was leaking but it should have stopped when the oil leaks down past that level unless fuel kept filling it up past the screw (unlikely to be a continuously noticeable leak). You probably had a separate fuel leak as I mentioned above.

One of your injector fuel lines looks even way more rusted than one of mine that developed a pinhole leak. It was an atomized spray for a couple days as it got worse and worse. The first day I noticed about a pint or two in the drip pan and we started noticing the fuel smell, but couldn't find the leak once the engine was shut down. By day three, the leak doubled in severity and the smell strong enough to check underway and that's when I notice the fuel mist.

The leak was a pinhole in one of the sharp fuel line bends where the paint was cracked and the line rusted through at that point.

So the are many points where those engines can leak and still be difficult to find the leaks.
 
Last edited:
I have not ran the motor Beyond 1 minute after putting in the new screw and filling it up with oil and Lucas. While under power we were watching for a diesel spray of any kind and we saw nothing and the only place where there was wetness from diesel came from the seep hole if I'm saying the term correctly.
 
I have not ran the motor Beyond 1 minute after putting in the new screw and filling it up with oil and Lucas. While under power we were watching for a diesel spray of any kind and we saw nothing and the only place where there was wetness from diesel came from the seep hole if I'm saying the term correctly.

I am not familiar wih your pump (in the videos) so I have no idea what the hole you repaired was.

If you add a little too much oil to the pump, does it come out that hole with the new bolt out?

If so and a gallon of fuel leaked out after only one run of 10 hrs.... I can't say for sure but that doesn't seem right that fuel winds up where oil should be and that much diesel is definitely bad.
 
I am not familiar wih your pump (in the videos) so I have no idea what the hole you repaired was.

If you add a little too much oil to the pump, does it come out that hole with the new bolt out?

If so and a gallon of fuel leaked out after only one run of 10 hrs.... I can't say for sure but that doesn't seem right that fuel winds up where oil should be and that much diesel is definitely bad.


Yes it will come or the hole.. it's your overfill hole. I am trying to contact the guy on ebay to see if i can send it in for a reman. Exchange. About ($850,00) BUT i cant find instructions as to HOW to take it off and send it off..

Also, if i sailed like it is AND the fuel did raise the oil level, did i just make things worse as in now i have to deal with the motor to.?
 
Last edited:
The FIRST thing I would do is call Brian at American Diesel. He is the guru on Lehmans. He is always happy to help. Since he will be selling you parts throughout your ownership of the Lehman it is good to establish a relationship with him. 804-435-3107
 
I am not really an engine guy, but the only way to tell if fuel got in the crankcase is to take and get an oil sample.

Now a good nose and fingertips can sometimes tell oil fuel dilution and a better method is the blotter test (Google it) ....but the best for us amateurs is an oil sample.

If you do have a high fuel content in your engine oil, a call to American Diesel or other Lehman experts like Bomac Engineering would be my next step while trying to get the pump rebuilt.

If you google Lehman injection pump removal with Trawler Forum in the sentence, you may get a hit on removal instructions. Replacing it is pretty tricky with timing the engine with the new pump....
 
Hi there fellow GB woodie owners!


I just wrapped up 5 months of Lehman injection pump pain and anguish. Our 1968 Grand Banks had one of the rare old Lehmans with a rotary injection pump, which long story short wasn't rebuildable due to discontinued parts, so after consulting with Brian at ADC, I converted to a Simms pump like you have.


If you're getting excessive diesel in the cambox of the Simms pump, the likely cause is excessively worn plungers and barrels. Rebuilding the pump is the only cure for that, and it needs to come off and taken to a diesel shop to be done so the phasing and fueling can be set properly. Be sure the shop actually replaces the plungers and barrels, I got a "rebuild" that didn't include that, and had to remove and reinstall my pump twice before it finally got done properly.


If you decide to do the removal and reinstallation yourself, definitely consult with Brian at ADC, but here is what I'd recommend based on my own recent experience.


First, set your engine to proper pump timing:


1. Use zip ties or something similar to restrain the engine shutoff lever in the shutoff position so you don't accidentally start your engine during the next step.


2. Remove the pump timing inspection plug, have a helper watch through the window and slowly turn the crank pulley bolt in the engine's normal direction of rotation (counterclockwise when viewed from the flywheel end) until the pump timing mark is aligned. It should look like this:
pump2.JPG



3. If you would like to verify your timing is correct, you can remove the inspection cover on the lower starboard side of the bellhousing and use a borescope camera or flashlight and mirror to check the timing mark is set to 20* BTDC #1 piston compression stroke.


4. Remove the injector lines and fuel feed line from injection pump.


5. Remove the four bolts and one nut attaching the pump to the front timing cover. Slowly work the pump out of the aperture, there may be some resistance as it is a helical gear and will turn slightly as you pull it out. This is what you'll end up with:


pump1.JPG





Once you've removed the pump DO NOT turn the engine. When going for a reinstall, you can now simply line up the pump timing mark and reinsert. This can be fiddly again due to the helical gear causing the pump to turn as you insert it. The trick is to figure out through trial and error how far rotated you need to start your insertion to end up with the timing mark aligned and the pump sitting vertical when fully inserted. There is some slight rotational adjustment possible by the slotted mounting holes to fine tune this.


As to what will happen if you continue to run your engine with the pump as-is. There should be a breather line on that pump, on the starboard side slightly higher than the level plug, as long as this is free, you can connect a piece of hose to it and run to a catch container. Often this breather is plugged and a small hole is drilled in the oil fill cap instead, if that is the case, than excess diesel will eventually leak out that hole.


I'm happy to add additional detail if helpful for anyone taking this on.
 
The FIRST thing I would do is call Brian at American Diesel. He is the guru on Lehmans. He is always happy to help. Since he will be selling you parts throughout your ownership of the Lehman it is good to establish a relationship with him. 804-435-3107

Talk to Brian and he felt that because the diesel was making it into the area it prevented the pump from running dry and everything I did to this point is good to go he said just keep an eye on it but he felt I should be fine will you reminded me to check it after 50 hours and I told him does he think for the first time I should check it at 20 to 25 he thought that was a great idea just to be sure but he felt everything was fine and there was no need to rebuild it
 
I am not really an engine guy, but the only way to tell if fuel got in the crankcase is to take and get an oil sample.

Now a good nose and fingertips can sometimes tell oil fuel dilution and a better method is the blotter test (Google it) ....but the best for us amateurs is an oil sample.

If you do have a high fuel content in your engine oil, a call to American Diesel or other Lehman experts like Bomac Engineering would be my next step while trying to get the pump rebuilt.

If you google Lehman injection pump removal with Trawler Forum in the sentence, you may get a hit on removal instructions. Replacing it is pretty tricky with timing the engine with the new pump....

There is no diesel in the oil it was just in the fuel injection pump
 
Hi there fellow GB woodie owners!


I just wrapped up 5 months of Lehman injection pump pain and anguish. Our 1968 Grand Banks had one of the rare old Lehmans with a rotary injection pump, which long story short wasn't rebuildable due to discontinued parts, so after consulting with Brian at ADC, I converted to a Simms pump like you have.


If you're getting excessive diesel in the cambox of the Simms pump, the likely cause is excessively worn plungers and barrels. Rebuilding the pump is the only cure for that, and it needs to come off and taken to a diesel shop to be done so the phasing and fueling can be set properly. Be sure the shop actually replaces the plungers and barrels, I got a "rebuild" that didn't include that, and had to remove and reinstall my pump twice before it finally got done properly.


If you decide to do the removal and reinstallation yourself, definitely consult with Brian at ADC, but here is what I'd recommend based on my own recent experience.


First, set your engine to proper pump timing:


1. Use zip ties or something similar to restrain the engine shutoff lever in the shutoff position so you don't accidentally start your engine during the next step.


2. Remove the pump timing inspection plug, have a helper watch through the window and slowly turn the crank pulley bolt in the engine's normal direction of rotation (counterclockwise when viewed from the flywheel end) until the pump timing mark is aligned. It should look like this:
pump2.JPG



3. If you would like to verify your timing is correct, you can remove the inspection cover on the lower starboard side of the bellhousing and use a borescope camera or flashlight and mirror to check the timing mark is set to 20* BTDC #1 piston compression stroke.


4. Remove the injector lines and fuel feed line from injection pump.


5. Remove the four bolts and one nut attaching the pump to the front timing cover. Slowly work the pump out of the aperture, there may be some resistance as it is a helical gear and will turn slightly as you pull it out. This is what you'll end up with:


pump1.JPG





Once you've removed the pump DO NOT turn the engine. When going for a reinstall, you can now simply line up the pump timing mark and reinsert. This can be fiddly again due to the helical gear causing the pump to turn as you insert it. The trick is to figure out through trial and error how far rotated you need to start your insertion to end up with the timing mark aligned and the pump sitting vertical when fully inserted. There is some slight rotational adjustment possible by the slotted mounting holes to fine tune this.


As to what will happen if you continue to run your engine with the pump as-is. There should be a breather line on that pump, on the starboard side slightly higher than the level plug, as long as this is free, you can connect a piece of hose to it and run to a catch container. Often this breather is plugged and a small hole is drilled in the oil fill cap instead, if that is the case, than excess diesel will eventually leak out that hole.


I'm happy to add additional detail if helpful for anyone taking this on.
Thank you for the pictures and the instructions I'm going to continue to look at this thread in case if I need to actually do the swap out Brian didn't think that was necessary yet
 
Yes, if your engine is running well and your injection pump doesn't seem to be making a crazy amount of oil, by all means put a hash mark in the win column and go boating!
 
If you are good to go.....where did the gallon of diesel come from?
 
One unrelated tip since I saw on YouTube that your port engine oil was low. You cannot trust the factory low mark on the lipstick. Based upon the actual installation angle of the engine many owners (myself included) have found that if you fill it to that full mark it just pukes oil out until it gets back to what is an actual normal "full" level. Then if you are not actually burning oil it likely will remain at that level for a long time. Perhaps even until your next oil change. I wouldn't be quick to add more oil if it is just at the low mark on the lipstick. Just check frequently and only add more if the level keeps dropping further. I am sure there are other threads with better descriptions of this phenomenon.
 
One unrelated tip since I saw on YouTube that your port engine oil was low. You cannot trust the factory low mark on the lipstick. Based upon the actual installation angle of the engine many owners (myself included) have found that if you fill it to that full mark it just pukes oil out until it gets back to what is an actual normal "full" level. Then if you are not actually burning oil it likely will remain at that level for a long time. Perhaps even until your next oil change. I wouldn't be quick to add more oil if it is just at the low mark on the lipstick. Just check frequently and only add more if the level keeps dropping further. I am sure there are other threads with better descriptions of this phenomenon.
+1
Even SB found the level it wanted and kept once I left them alone and just checked before each trip to confirm.
 
Just got an email from a yachting/engine guru on my question back in post #23....

"If you are good to go.....where did the gallon of diesel come from? "

Good question! If the plungers or bores are worn to the extent that they leak that much fuel then they are certainly worn out or there is some other mechanical damage elsewhere. Either way, the pump is shouting that it needs help. If it is the plungers or bores, at some point the engine will no longer make full power or if it is just one the other cylinders will have to be slightly overfueled to make up for the loss of power. Sure, the pump will keep the engine running at what might feel like normal but that will not last much longer before more expensive problems show up.
 
Grand Illusion-
Your description of how to remove and replace the injection pump was excellent and should be preserved here for future reference for anyone about to tackle this project. Good of you to take the time to post it.
Welcome aboard.
Stick around!
 
Thanks Mike, I thought about taking some video when doing mine, but I just didn't have it in me to add all the extra time required to do that. If there's anything from my experience that might be helpful to someone else doing this work, I'm more than happy to share it.
 
Back
Top Bottom