Suzuki DF140 Making oil- tried everything I think

[redlowrey]

Mate if an injector was stuck open, the cylinder would miss and it would be blowing white smoke out the prop, and when you removed the plugs, the cyl that was missing would be soaked in fuel. Your plugs are a perfect colour and the air fuel ratio would be close to 14 to 1.

The only way raw fuel could get blown past the piston rings is on the intake stroke, where the ecu will put a ground on the injector driver and squirt fuel towards the inlet valve. The inlet valve will open just before tdc and when the piston moves down the cylinder it will draw in an air fuel mixture which will be compressed as the piston moves towards tdc then ignited by the spark plug.

Now just say one piston had both the top ring and second ring gaps aligned, and the top oil scraper ring as well, this would allow fuel to get past into the sump, but in reality the temperature of the piston crown would evaporate it.
If this was a problem it would effect every car berated and port fuel injected engine made. Can you give a bit more history on the engine, like are they genuine hours, was the problem there when you bought it or did it happen later. What the heat range of your spark plugs, they should be bkr6e.

If fuel was sprayed directly on to the cylinder wall in a solid mass I would think the problem could occur, but it doe's not it hits the inlet vave

[srowejr]

So a bit more history for you, bought it used with about 128 hours on it back in February. I have the Suzuki SDS software to hook up the engine to verify. Have around 150 hours on it now. It seems to run well, no smoke or anything. I was thinking if the ecm doesn't close an injector for some reason after the motor is turned off, then excess fuel could possibly leak into crankcase then down into oil.

I am grasping at straws here for sure, I just don't know where else to go with this.

Would doing a leakdown test be of any use here? Compression test was 210 on 3 cylinders and 215 on the 4th. Looked good from that aspect.... I have never done a leak down and if anyone has some detailed instructions on how to do it that would be much appreciated. The equipment doesn't look expensive compared to a shop rate.

Thanks for the great explanation btw!! I learned a lot!!!

[srowejr]

Oh and the engine has done it since I bought it and the plugs were replaced with the ones called for in the manual.

[redlowrey]

Do your injectors sit in the head or are they in the inlet manifold.