How is gas filling up my crankcase? 2017 Merc 9.9 Pro Kicker

[onepyramid]

My assumption has been, after three unsuccessful attempts to solve the problem by rebuilding the fuel pump, that this was the culprit for gas getting into my crankcase.

I am not a newbie to engines, or outboards, and rebuilding this fuel pump certainly does not stretch my mechanical abilities. But it keeps happening and I am racking my brain to find another cause.

So....is there some other way this could be happening? Can gas somehow run through the carb in such quantities as to fill the crankcase in less than an hours run time?

Thanks, in advance, for all help.

 

[William01]

Mechanical fuel pump leaking fuel into the crankcase?

VST float set too low and the excess fuel is getting pushed out the vent line into the crankcase? Reread your post, carb not fuel injection

 

[onepyramid]

Mechanical fuel pump leaking fuel into the crankcase?

VST float set too low and the excess fuel is getting pushed out the vent line into the crankcase? Reread your post, carb not fuel injection

VST? Is this just the float in the bowl on this small carb?

 

[William01]

VST Vapour Separator Tank, supplies fuel the fuel injectors, you have a carburetor so no VST

 

[onepyramid]

Is there some way for gas to bypass the carb? When I was removing the carb from the engine, as soon as I loosened the attachment bolts, fuel began leaking out...quite a bit of fuel. That is now what I would have expected if the bowl of the carb was the only thing holding a normal amount of fuel.

 

[flyingscott]

Is there some way for gas to bypass the carb? When I was removing the carb from the engine, as soon as I loosened the attachment bolts, fuel began leaking out...quite a bit of fuel. That is now what I would have expected if the bowl of the carb was the only thing holding a normal amount of fuel.

Yes your float could be bad or misadjusted. And I mean the float in the carb. Or the needle and seat are bad.