Unburned Fuel Running Down Side Of Lower Unit

[bertherr]

My 1985 115hp Evinrude will have fuel on the port side of the lower unit after running. It runs out from under the taperd cowling below the power head. I also noticed fuel on the skeg below the prop. The engine runs fine at speed, most of the time, but does not idle well. It does develop a miss that goes away by it self from time to time. I did de-carb recently. I removed one plug wire at a time, and replaced it, with the engine at idle. The engine would almost quit on all but the port side lower cylinder. The engine idle did not change much when I removed this wire. You could hear the spark jumping to the plug. Compression is 118-120 on all four cylinders. I'm thinking a bad crankshaft seal. What do you think? Thanks, Bert.

 

[Terry H]

Re: Unburned Fuel Running Down Side Of Lower Unit

I had an identical problem with a 140hp motor a couple of years earlier than yours...I thought the same thing...lower seal. Turned out to be a 1/2" hole in the crankcase below the carbs on #4 cyl. I assumed a rod had tried to exit there with the previous owner and he welded it up...didn't hold. He got is motor back and I got my money and bought another motor. just a Thought

 

[Forktail]

Re: Unburned Fuel Running Down Side Of Lower Unit

Compression is good. Could be a crank seal, but most likely carburetion.<br /><br />Some of the older motors don't run well in a high trim position. The carbs tend to flood the engine. Check your carburetor float height. You could also have a needle and seat stuck open allowing excess fuel into the engine. Your intake reeds (if this motor has them) might not be sealing properly either allowing fuel to escape back into the intake.

 

[Kuni]

Re: Unburned Fuel Running Down Side Of Lower Unit

is the lower cylinder spark plug rusty or wet with water if so most likely is bottom crank seal leaking.(sucks water through)<br />just a thought.<br />tight lines.