White Smoke

Kevin_G · Feb 26, 2005

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 · Feb 26, 2005

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 · Feb 26, 2005

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 · Feb 26, 2005

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

Kevin_G · Feb 26, 2005

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 · Feb 26, 2005

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 · Feb 26, 2005

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 · Feb 26, 2005

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 · Feb 27, 2005

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 · Feb 27, 2005

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.

captain71c · Feb 27, 2005

That was my thinking. A critter or a left over rag got pulled into the intake manifold. I once found a whole box of candy canes that had been pulled into the air cleaner of a fire truck that I was working on. (Santa tours at Christmas).Stranger things have happened. It comes down to the three things that an engine needs to run. A source of ignition(compression,Heat), Fuel at the right time and in the right quanity and air. The amount of white smoke makes me think an air or over fuel problem.

BigAl · Feb 27, 2005

You are right . I stand corrected . I was just locked into a "excess fuel" mindset and never thought about the air supply . Would not the tractor tend to produce more of a black smoke than white if it was a air flow problem ? Just a thought .
Big Al

Lenarguy · Feb 27, 2005

I would recommend that you get the compression tested. Make sure that you have good compression in this cylinder before you remove the pump. When you crack the line does it seem like the same amount of pressure as the other line?

normde2001 · Feb 27, 2005

"I left the muffler off and after a couple minutes running, diesel trickles out of rear cylinder exhaust port."

Considering that the rear cylinder does not fire at all, that seems to eliminate fuel and muffler as the problem, leaving only air intake and compression.

chriswheeler · Feb 27, 2005

Have you checked to see that the exaust valve isn't stuck or checked the valve clearance?? Sounds like a open, or burned, or dirty exaust valve. ( Not enough compression to fire fuel and raw fuel in exaust ) I think I would look at this first before any fuel pump work.
Chris

Kevin_G · Feb 27, 2005

I fiddled with tractor again today. Engine running and sprayed small amounts of WD-40 in intake.
Engine increased in RPM and white smoke literally stopped.
After WD-40 burns off, white smoke reappears and RPM decreased. If it could be the injector pump,(since I swapped injectors and problem stayed with back cylinder), does anybody know where I can get a rebuild kit for the injector pump? Or could it be some other problem still since I'm pretty much force feeding fuel to this cylinder?
Both injectors seem to be delivering the same amount of fuel when pulled out of head, laid on side and engine turned over with starter. /forums/images/graemlins/confused.gif

captain71c · Feb 28, 2005

You would need test equipment to acually measure the amount of fuel comming out of each injector for any type of compairison. Your local auto parts store might know of a rebuilder in your area for the pump. I looked in some of my manuals and they stated that white smoke is commonly caused by a bad or out of time injector pump.

ducksjunk · Feb 28, 2005

You've already said that the compression was good, and if the injector was bad the problem should have moved from one cylinder to the other when you did injector swap. Try spraying your wd 40 around the area where the intake manifold meets the head to be sure you don't have a gasket leak.
R.