Oil in Bilge..More Oil in the Engine!

[Cheechako]

the absorbant mats cleaned up the bilge pretty good. I think it's an unrelated issue...I must have lost some oil changing the filter a while back....movement of the boat and more bilge water getting it in. I,m hoping I see a big crack in the lift pump diapragm!

[hellosailor]

After the first time you have to service a diaphragm pump and put up with the nuisance factor, good old simple reliable inexpensive diaphragm pumps seem more like land mines and you may want to make long range plans to replace it with an unreliable newfangled electric pump. (Yeah, I know, when the power fails an electric pump does too.)

"If I put the oil I took out in a glass jar will the fuel separate from the engine oil? " Well...you should also be able to kludge up a way to compare the density (the specific gravity) of your mystery sample versus a real oil sample poured from a fresh bottle. If there's a brewing supply store in town, they might even have one of those cheap little sg float gizmos in stock. Maybe if you tie the jar in a small sling and whirl it around to centrifuge it, that would encourage the settling?

[senormechanico]

Hellosailor is talking about a sg meter, aka specific gravity or hydrometer.
I use one for my batteries, and another for my wine making.

About five bucks at a hardware or automotive parts house.
I like the sloped board viscosity test.
Betting on the lift pump diaphragm...

[Cheechako]

Spent the morning standing on my head bent around the back side of the engine. Removed the lift pump. I dont see any evidence of pinholes or leaks in the lift pump diapragm, I'm rebuilding it anyway, but not hopeful at this point..Never had an issue in 30 years with diesel fuel in the oil...guess there's a first time for everything. So there must be a seal on the shaft of the injection pump....is it that simple a failure? Too bad IP's are so complicated to get on/off and timed etc...

[Troubadour52993]

I agree the IP is a pain, heard it needs to be sent off for overhaul when problematic. My 4-236 manual says sump capacity for marine sump is 8.7 quarts, 9.9 total capacity. I know my manual oil change pump drips into the bilge unless I plug it. Good luck!

[Cheechako]

OK, my mechanic had an adaptor made to do a compression test on the Perkins 4-236. Cyl 4 was real low. We took the rocker cover off and the intake pushrod was bent and jammed and against the rocker (in the wrong spot) New pushrods on the way..I sure hope that is all it is...but WHAT WOULD CAUSE THAT????

[Fishman_Tx]

Loose rocker arm?

or

one cause could be hydro-lock. i.e. a cylinder full of fuel, which would be caused by a plug not firing repeatedly (filling it with unburned liquid fuel). this would be a bad coil, plug, plug wire, distributor cap or rotor, ect...
another cause could be pre-ignition. a cylinder firing when it is in the wrong part of its stroke, thereby causing the explosions "up-force" to fight either the valves attempt to open, or forcing a not fully seated valve closed. this would be caused by the timing being off its mark, though your damage would be more wide spread as it would effect multiple cylinders unless this is a single cylinder engine.
also, it could be caused by a stuck lifter, though that would ultamately lead to one of the 2 above causes. there could be other causes, but thats the most likely 3 (short of a bad cam, broken timing belt/chain, ect...).

from wiki...

[hellosailor]

Bent pushrod...damage from water in the cylinder, which prevented a valve from opening into it, which in turn jammed back to the pushrod?

[Stillraining]

You will know if you have a bent rod ..She will still be low on compression..and if you decide to get her fired anyway...She will still pour out white smoke if you do.

[hellosailor]

Instead of doing a head job and then having to redo it for a bent rod, why not pull the rods & check them while the head is off the first time? Or, if one is confirmed bent...condemn and replace them all rather than risk another failure.

[daddle]

Must be diesel in the oil. There's nothing else it could be, right? Something's leaky and the extra smoke is a clue too.

From the injector pumps I've torn down I don't see how much diesel could get into the block and still have a running engine, but....

[Cheechako]

It's a bent rocker arm push rod...not a piston connecting rod... no head removal required...yet! I like the water in cyl theory..it is the aft most and lowest cylinder and the exhaust sits half under water when not running There is no vented loop on the water hose going into the exhaust elbow...not sure if that would prevent it..I could only get a loop up maybe 8" if I put one in.... I cant find a flapper to fit the 3.5 dia exhaust outlet....

[Troubadour52993]

I was going to say water in the cylinder too - happened on my 4-236. You need a vented loop somewhere after the raw water pump, it doesn't have to be right as it goes into the exhaust elbow. I have a run of hose from the raw water pump discharge to the inside of a cabinet in order to get the vented loop high enough (min 6" above loaded, heeled, waterline, 12" is better) then run it back to the heat exchanger. Check all your rods while the rocker is off!

[Stillraining]

Originally Posted by Cheechako

It's a bent rocker arm push rod...not a piston connecting rod... no head removal required...yet! I like the water in cyl theory..it is the aft most and lowest cylinder and the exhaust sits half under water when not running There is no vented loop on the water hose going into the exhaust elbow...not sure if that would prevent it..I could only get a loop up maybe 8" if I put one in.... I cant find a flapper to fit the 3.5 dia exhaust outlet....

Yes I know ..I was just mentioning compression would still be low if it were, and there will be white smoke if so...Once the new push rod was installed.

[hellosailor]

"I cant find a flapper to fit the 3.5 dia exhaust outlet.... "
Sheet of 1/4" neoprene or buna-n rubber from McMaster or Grainger, cut to fit generously over, attached with two stainless screws or a piano hinge at the top. No big deal.