White Smoke

[Kevin_G]

On my Yanmar 240, White smoke poures from exhaust. These are things I did trying to fix the problem with no success. Back cylinder is dead, fuel line can be removed and engine stays running on one cylinder. Swapped injectors and back cylinder still dead. Both injectors removed and cranked engine and fuel supply is great from both injectors. Compression checks good on both cylinders. Out of desparation, pulled head thinking blown gasket. While I had it that far, pulled pistons and everything looks almost new. Replaced head gasket with new one and checked fuel timing and still doing same thing. I'm stumped. Please help. Thanks /forums/images/graemlins/confused.gif

 

[BigAl]

Well , It sounds like you are really covering everything I can think of . White smoke is unburned fuel and a lot of it . Could the valve be stuck open some how not allowing it to build compressioin to fire ? Wait you covered that ! You say you have good compression on the cylinder. Are you sure you are in time and not 180 out ? What I am saying is it could still be building pressure but the timing is still off . How long has it done this ? Give me all the infor you can think of and I will check with a diesel buddy who is a mechanic .
Big Al

 

[Lenarguy]

How did you check the compression? Did you check the head for cracks or damage?
I am not doubting your abilities just need more information.

 

[bruce1966us]

If all your checks are correct, seems like you have narrowed it down to the injection pump.

 

[Kevin_G]

For a couple of weeks it was hard to start (crank for 15 seconds at the most). I was running it not hard, then it started this problem. While I had the head off, I sent it to a machine shop and checked for cracks and all valves were lapped and seated. Also after reassembly, valves were adjusted. I'm sure timing is correct, even checked that several times.

 

[captain71c]

Since you have tried all the simple fixes. My first guess would be a faulty injection pump. What about an obstruction in the intake manifold to the rear cylinder?

 

[BigAl]

Hi Captain ,
I don't think they have that type of intake manifold . I believe it is a direct injection through the head . I do agree ,it sounds like a bad pump . I broke a flex plate on my old JD crawler pump and it drove me nuts finding the problem .
Big Al

 

[California]

Sounds like you have checked all the reasonable causes and all that is left is the unlikely ones.

One more thing to check - Yanmar calls the cylinder nearest the flywheel "#1", not the front cylinder like most othe manufacturers. If the front cylinder was used to time it then the injector may be firing at the wrong time.

Is it raw diesel making that white cloud or could it possibly be water?

 

[Kevin_G]

I have a Yanmar service manual and went off the rear cylinder as #1. I'm sure it is raw diesel. I left the muffler off and after a couple minutes running, diesel trickles out of rear cylinder exhaust port. One other thing I forgot to mention was when I break the fuel line to the rear cylinder, white smoke almost stops. And break line to front one engine dies.
Does anyone know a good place to get repair parts for the injector pump if this could be the problem? Hoye Tractor supply doesn't have much for the 240.

 

[ducksjunk]

Intake manifold still has to supply sufficient air. It is possible that sone little critter has set up housekeeping in the manifold cutting off the air to that cylinder. It could be worth a look before building the pump.