Any 2 stroke gurus?

Actually it's a problem with my 1980 Kawasaki Invader 440 Liquid (snowmobile) so not sure if this thread will be deleted but I thought someone might have some insight.

Put my sled away in the spring running great. Didn't drain the gas and next winter I have a crank case full of gas. Removed the pipes and carbs and then started the sled to let it run off the gas in the crank until most was burned out/off (yes it would start and run w/o carbs) .

Between the carbs and tank is a stand alone Mikuni fuel pump that runs off crank vacuum. Took pump apart and it looks great. Had a local shop check my float needles (checks them with a vacuum gage or some set up). He says they're fine. Not surprising they're only a few years old.

How can that fuel be making it into the crank??

Any suggestions or thoughts appreciated.

you listed the 2 ways fuel can get in
there is a problem with one of them
my guess would be the carbs

does the tank have a shut off?

My thoughts exactly. I can only see those two ways but neither seems the culprit.

I also thought about a fuel line shut off.

timtune said:

My thoughts exactly. I can only see those two ways but neither seems the culprit.

I also thought about a fuel line shut off.

Click to expand...

plastic tank?
if so I'd drain it for the off season
only reason to have it full is to prevent rust

JavaFan said:

plastic tank?
if so I'd drain it for the off season
only reason to have it full is to prevent rust

Click to expand...

You might want to overhaul that fuel pump. Some fuel pumps also work as shutoffs when there is no vacuum, if the pump is no closing the fuel circuit when the engine shuts off fuel can drain from the fuel cell through the pump and into the carbs when if the fuel cell is higher than the carbs. If any single carb is not sealing, the fuel ends up in the crankcase.

This happens a lot with motorcycles that have vacuum activated petcocks (I have a couple of Viragos that suffered from this).

An easy solution is to install a manual petcock between the fuel cell and pump, this might be easier than doing the carbs and fuel pump on an older machine.

What Mad Mike said.