Oil level "Rising"?

[Cheechako]

I've had this happen on a Perkins. One of two things:
1) the pushrod has come off one of the rockers on one cylinder. Remove the valve cover and look to see if one is not contacting the rocker.
2) (more likely) You have a badly fouled injector, it is washing the cylinder with fuel and it goes into the oil. Rebuild that injector.
This seems to happen when boats are not run very often. It's surprising how smooth a 4 cyl can run with one bad cylinder.
While it's running, crack the injector nut on each cylinder. The bad one will have little or no effect on the engine. The good ones will make the engine slow down and get rougher.

STOP running your engine until you figure this out. You can likely still save that cylinder if you get the injector/pushrod fixed.
One more thing: If the push rod is off..... ask yourself if it's possible you were getting some seawater into the engine. If the boat is sitting at a dock so that small wavelets push into the exhaust it could gradually push some water into the engine.. maybe just enough (if you were lucky) to cause the pushrod to pop off from the pressure when you started the engine.

[donradcliffe]

While the lift pump is cheaper and easier, my best guess is that your problem is a leaking seal in the injection pump. You will probably have to get the injection pump rebuilt--the going rate is about $500-$800 if you pull the pump yourself.

[Cheechako]

Originally Posted by Cheechako

I've had this happen on a Perkins. One of two things:
1) the pushrod has come off one of the rockers on one cylinder. Remove the valve cover and look to see if one is not contacting the rocker.
2) (more likely) You have a badly fouled injector, it is washing the cylinder with fuel and it goes into the oil. Rebuild that injector.
This seems to happen when boats are not run very often. It's surprising how smooth a 4 cyl can run with one bad cylinder.
While it's running, crack the injector nut on each cylinder. The bad one will have little or no effect on the engine. The good ones will make the engine slow down and get rougher.

STOP running your engine until you figure this out. You can likely still save that cylinder if you get the injector/pushrod fixed.
One more thing: If the push rod is off..... ask yourself if it's possible you were getting some seawater into the engine. If the boat is sitting at a dock so that small wavelets push into the exhaust it could gradually push some water into the engine.. maybe just enough (if you were lucky) to cause the pushrod to pop off from the pressure when you started the engine.

With the injector washing the cyl it would put about 1.5 quarts in the oil in 7-8 hours.

[prof_mariner]

Too soon to rule anything out, but I'm going to check the lift pump first, $53 bucks isn't that much and if I'm wrong a spare pump in the boat isn't a bad thing to have. I sure hope it isn't something more severe and I really doubt it is. It seems to run as smoothly as the day it was inspected. Starts up immediately too. Fingers crossed it's that pump...

[prof_mariner]

I worked on the engine a bit more since my last post. I checked the coolant level (just to make sure) and it is about where it should be. So I'm pretty confident my initial guess (that fuel is leaking into the oil pan) is what's happening.

I ordered a new lift pump yesterday from S&W Diesel and had a chat with one of the fellows there. Turns out they do a lot of Perkins 4108's and he said fuel in the oil pan was either the lift pump ($60 part) or the high pressure pump ($700 rebuild) and agreed it wouldn't hurt to swap the lift pump first.

I went about pulling the old one off today while I wait for the new one to arrive. After it was removed, I disassembled it to check the diaphragm but didn't see any obvious leaks. I reassembled it and gave it a simple suction test (worked the plunger and covered the intake with my finger). Seemed to hold suction OK. Hmm.... Sure hope that's the problem otherwise it's time to pull out the big credit card. ;P

[DeepFrz]

Search around the site a bit for HP pump rebuilds. There seems to be a large margin in price, from about $350 to over $700 depending on who does the rebuild. Maybe some of the folks that have had pump rebuilds will comment here.

[Cheechako]

If the lift ump isn't it don't forget to do the running/crack injector test before jumping to bigger things.

[prof_mariner]

Originally Posted by Cheechako

If the lift ump isn't it don't forget to do the running/crack injector test before jumping to bigger things.

I read that suggestion but I'm not clear what that actually tests. As I understand it, injectors are simply spray nozzles, right? Or do they have some sort of shut off functionality also?

[Cheechako]

when operating properly the injector will atomize the fuel. when not, it may spray a stream, which goes unburned and goes past the rings into the engine oil.

[Capt Doug]

Detectives sure help...
I pulled all four injectors, the #1 (?) closest to the flywheel came out all covered with dirty oil. trip to injector shop for tests. The fluid I pumped out of the engine pan was not milky, but was about two quarts more than oil capacity. My cooling system tank was mostly dry. I have a shallow bilge under the engine to catch anything, including tools. There was no green coolant or dirty oil there. Perkins 4-107 manuals not much help, found a you-tube video on how to remove injectors that don't want to move, very good and as mentioned they are out. Was planning on sending them out anyway.

[prof_mariner]

Originally Posted by Cheechako

when operating properly the injector will atomize the fuel. when not, it may spray a stream, which goes unburned and goes past the rings into the engine oil.

Perhaps some of that unburned fuel will slip past the rings and into the crank case, but won't most of it get pushed out into the exhaust? So if that were the case, wouldn't I see lots of unburned fuel in the exhaust (a sheen in the water around the exhaust exit on the boat)?

I changed the lift pump a few days ago, and for good measure I changed the engine coolant. I ran the engine under load for about an hour. Oil and coolant levels were unchanged. The exhaust looked very clean (no indication of unburned fuel, steam or burning oil).

Now I'm waiting and checking the oil level on a daily basis to see if it changes. Hopefully it doesn't. If the oil level goes up I'm afraid the next thing to check will be the hp/injector pump (which is in an awfully hard spot to get at on my boat).

[lorenzo b]

Do not read a dipstick by just pulling it out, they often have a sealing gasket to keep oil from spraying out and you could have a pressure difference in the tube that may give you a false reading. Take the stick out, clean it, put it back in all the way, and then pull it and read it.

[prof_mariner]

Originally Posted by lorenzo b

Do not read a dipstick by just pulling it out, they often have a sealing gasket to keep oil from spraying out and you could have a pressure difference in the tube that may give you a false reading. Take the stick out, clean it, put it back in all the way, and then pull it and read it.

That's exactly how I do it, but I never knew why it made a difference. Thanks for the tip!

[Pirate999]

Had this problem last October. Sounds like it was your lift pump so that's good. You'll need to run it more than an hour though, but you probably know that. Mine turned out to be the injector pump. Removed it myself, had it rebuilt and reinstalled it myself. Hell of a thing but a good learning experience.

[Cheechako]

Originally Posted by prof_mariner

Perhaps some of that unburned fuel will slip past the rings and into the crank case, but won't most of it get pushed out into the exhaust? So if that were the case, wouldn't I see lots of unburned fuel in the exhaust (a sheen in the water around the exhaust exit on the boat)?

I changed the lift pump a few days ago, and for good measure I changed the engine coolant. I ran the engine under load for about an hour. Oil and coolant levels were unchanged. The exhaust looked very clean (no indication of unburned fuel, steam or burning oil).

Now I'm waiting and checking the oil level on a daily basis to see if it changes. Hopefully it doesn't. If the oil level goes up I'm afraid the next thing to check will be the hp/injector pump (which is in an awfully hard spot to get at on my boat).

I'm going by one experience with a bad injector. It gained about 1.5 quarts in the crankcase in 8 hours run time. But the diesel had "washed out" the cylinder... and there was low compression. After the injector was repaired the compression came back to equal the other cylinders after about 1 + hour run time! But yes, there was a pretty good sheen on the water also.