Fuel/Oil coming out of Motor exhaust

[MelloLello]

I’ve got a Perkins 4.236 in my 1978 Freeport41 It runs great so far... except that EVERYTIME I run it, it would seem that some sort of fuel is mixed in with the water coming from the exhaust system?

Seems like some sort of fuel leak to me but I don’t have very much experience with diesel mechanics yet. Excited to learn though.

Anyone know where this is coming from?

Thanks.

[boatpoker]

Originally Posted by MelloLello

I’ve got a Perkins 4.236 in my 1978 Freeport41 It runs great so far... except that EVERYTIME I run it, it would seem that some sort of fuel is mixed in with the water coming from the exhaust system?

Seems like some sort of fuel leak to me but I don’t have very much experience with diesel mechanics yet. Excited to learn though.

Anyone know where this is coming from?

Thanks.

cracked cylinder head or head gasket.

[Lepke]

If you're getting a sheen on the water it could be motor oil or fuel. Excess fuel is usually a bad injector tip. Oil could be worn cylinders/rings or valve guide.
My Perkins 4108 was putting out a sheen. I bought new injector tips and that solved it.

[Paul L]

Does it only show up when you first start the engine and sit in idle? Does it clear up after the engine heats up?

[MelloLello]

Originally Posted by Paul L

Does it only show up when you first start the engine and sit in idle? Does it clear up after the engine heats up?

I only just noticed it today when I started it up here at the dock. I let it run at an idle for about 5 mins and and then I saw the sheen of “fuel” floating on the top of the water. I just shut it off after that. Didn’t really have a chance to warm up.

[MelloLello]

Originally Posted by Lepke

If you're getting a sheen on the water it could be motor oil or fuel. Excess fuel is usually a bad injector tip. Oil could be worn cylinders/rings or valve guide.
My Perkins 4108 was putting out a sheen. I bought new injector tips and that solved it.

This motor sat for a very long time before I purchased it. So I’ll definitely check the injectors and then go from there.

Would a can of sea foam green be a good thing to run through the fuel system to see if it clears those injectors out?

[MelloLello]

Originally Posted by boatpoker

cracked cylinder head or head gasket.

Dear lord. I hope not.

[CFS Klopas]

For me it lasts for a few hours after I start, otherwise same problem. My motor sat for a year as well. Yanmar diesel.

[shakey doug]

Easiest and Cheapest first, check all oil levels then go out and a good flogging at full throttle while monitoring all temps & pressures. If no better have G/box cooler pressure tested.

[MelloLello]

Originally Posted by shakey doug

Easiest and Cheapest first, check all oil levels then go out and a good flogging at full throttle while monitoring all temps & pressures. If no better have G/box cooler pressure tested.

All the oil levels are steady and good... I recently did a pretty decent run with the motor at about 2/3rds throttle for almost an hour.

The temps held really well at the 180 degree mark for the first half of the trip... then slowly raised in temp up to right around 193-195 degrees.

Seemed to be spitting coolant out of that top reservoir cap. I figured that the cap was bad or the thermostat needed to be replaced. Because the engine ran extremely well for a long trip.

Oil was just old. No watery/milky stuff in it at all.

Trans fluid was also good.

Just the “fuel” in the exhaust water.

[shakey doug]

The bit of info about the water spitting could be the key. forget my first post get a compression test done, symptoms point towards a Head Gasket or cracked Head. Is there any oily sludge on under on underneath of HX cap?
Good Luck.

[Rorzech]

Stuck injector maybe ?

[MelloLello]

Originally Posted by shakey doug

The bit of info about the water spitting could be the key. forget my first post get a compression test done, symptoms point towards a Head Gasket or cracked Head. Is there any oily sludge on under on underneath of HX cap?
Good Luck.

I wouldn’t call it sludge or oily. It kinda looks like rust? It’s gold in color and kinda powdery since it’s dried out.

[Valmika]

I just went through this myself last year. If your oil level is staying good then it is probably a stuck or clogged injector. You can have them rebuilt for less then a new one if you are in an industrialized area. The thing you said that worries me is that you were spitting coolant. If you start you engine with the coolant cap off are there bubbles in your coolant? If there are you need to pressure test your cooling system. If the pressure goes above about 20 PSI I would suspect a blown head gasket. Not necessarily a cracked head but something that should be taken care of soon. I had to do mine and I figured while I was there I would do the head and injectors. Mine has been running better then ever since I did it.

[grantmc]

Originally Posted by boatpoker

cracked cylinder head or head gasket.

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