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Pirate999 · 24-09-2013, 14:38

A couple of weeks ago, I notice that the oil level was high in my 4-108. Looked to be about 2qts high. There didn't seem to be a diesel smell per se but the viscosity was poor. I changed the oil and sent in a sample to be tested. Came back with significant diesel in the oil and low viscosity.

My mechanic suggested that it was the lift pump and that made sense. I ordered a new pump and changed it out myself the other day. Obviously, I also changed the oil. Easy access to the starboard side of the engine so it was easily completely.

I ran the engine for about an hour and checked the oil again. This time, it was seriously high and smelled strongly of diesel. Even after an hour the viscosity was nil.

Now during this time, bleeding the system, I noticed an ongoing small diesel leak from the injector pump. Naturally I thought I didn't snug everything down so I rechecked all the fitting. It still leaks. Hard to trace but possibly from the throttle area.

So, I have a new lift pump and a leaky injector pump and about 2qts of diesel in the engine in an hours worth of running.

My thought is that the injector pump is gone and it's not a bad (new) lift pump. Needless to say, removing and reinstalling the injector pump will not be as simple as the lift pump.

Thoughts?

Regards,

Ed

zeehag · 24-09-2013, 14:47

just before i took off my injector pump we found some diesel in my oil---it wasnt there until we removed the pump and again changed oil and dipstick location as wells so it is easier to read. placed it in alternative position.
take pix of engine before you dismantle it--we had to remove the bowman manifold and then we could reach the injector pump--i have a 4-108 without engine numbers. my block was forged in 1982

Pirate999 · 24-09-2013, 17:33

Thanks Zee...

Btw, the only thing I'd add is that the engine runs perfectly. Starts right up and runs smooth.

zeehag · 24-09-2013, 17:49

so did mine, sugaaahhh--until it ranaway it started right up and ran smoooooth --- just had a lil black smoke then a lot of black smoke then black fuel return then runaway then oil and diesel mixed together....

gjordan · 24-09-2013, 18:02

I recently changed out a failed lift pump on my diesel tractor. A few hours running time and I had high oil level. The NOS lift pump that had sat on a small dealers shelf for years, had a small crack in the diaphram. I removed the fuel lines from the lift pump, and plumbed in a 12 volt fuel pump from an auto parts store and solved the problem. 12 volt pumps are dirt cheep compared to an injection pump rebuild, so you might want to try that first. If it doesnt solve the problem, I would keep the 12 volt set up and fittings on board because lift pumps can be a real problem. I have owned 2 Perkins, and both of them had lift pump problems. The one I still own is now plumbed with a 12 volt pump. I go on the theory that you try the inexpensive fixes before you go to the thousand dollar fixes. I hope this helps. _____Grant.

zeehag · 24-09-2013, 18:09

luckily my rebuilds on my 2 pumps and the tranny heat exchanger totalled under 300 usd...life is good here....things do not have to cost so much.

gjordan · 24-09-2013, 18:20

I just saw Zees post and I agree. My previous Perkins ran perfect until it ran away. A runaway diesel is a horrible thing to hear. Long story short, I replaced the lift pump, and it only lasted a few weeks before it failed (didnt get fuel in the sump) and I went to the auto parts store and did a 12 volt system. It was still working fine 3 years later when I sold the boat. _____Grant.

DeepFrz · 24-09-2013, 19:37

Check the lift pump first. Its easiest and cheapest.

zeehag · 24-09-2013, 19:42

my injector pump failed but my lift pump did not fail.

gjordan · 24-09-2013, 20:11

Zee, yes injector pumps fail. My point (I think) is that lift pumps fail at a much greater rate than injector pumps, and for a relatively small cost, you can determine if it is really your injector pump, or your lift pump. -----just trying to (maybe) save somebody some money. _____Grant.

Cap Erict3 · 24-09-2013, 20:40

Run your engine and loosen your injector lines one at a time to see if it effects engine speed. If one seems to have little or no effect do a compression check.

A compression tester is a great tool. If compression improves after spraying oil in cylinder suspect rings.

donradcliffe · 25-09-2013, 17:42

The OP already tried replacing the lift pump. Leaking Injector pump seals are more common on 4108's than leaking lift pumps--vice versa for Yanmars.

Pirate999 · 25-09-2013, 18:11

Quote:

Originally Posted by donradcliffe

The OP already tried replacing the lift pump. Leaking Injector pump seals are more common on 4108's than leaking lift pumps--vice versa for Yanmars.

I did think I could have bought a bad lift pump so I replaced it twice just to make sure, knowing that the injector pump is not as easy. Takes less less than an hour to swap it out. Since my first post, I've talked to a couple of diesel mechanics and they think it's the injector pump seals.

So tomorrow I start by draining the system (header tank and exhaust manifold) and start the process of pulling the pump. I can see where with "great" access one could remove the pump without removing the exhaust manifold but given I only have "decent" access and I'm a big guy, removing the manifold should make life easier.

Other than access it really doesn't look that bad.

Open to suggestions and thanks for all the feedback.

scoobert · 25-09-2013, 18:31

being a diesel mechanic i would first check out the injector pump. if you have an inspection port on your timeing case cover, open it and watch.
if not the injector pump, leaking at the gear end, then an injector.
DO NOT run it with diesel in the oil. you will get cylinder wash, and premature ware.