8hp Mercury revs up, then stalls! See video

[henryst]

My year 2000 8hp Mercury starts right up on the first pull. But then, as it is idling, it begins to rev up on its own, then coughs/misses and continues to idle. Eventually, it will sputter out and die.

I thought it was definitely a carburetor/air leak/gas tank problem, but I've cleaned the carburetor thoroughly twice, tried a different gas tank and hose, and searched thoroughly for leaks. The spark is good on both cylinders.

Here is a video of the problem (listen with sound). Thanks in advance for any help!

**if you can't see the video, try to download it– worked for me**
View attachment IMG_2635 2.MOV

 

[flyingscott]

Have you adjusted the low speed needle? Sounds like a lean sneeze

 

[henryst]

Have you adjusted the low speed needle? Sounds like a lean sneeze

Hi Flying Scott,

Thanks for the response. The low speed needle has been adjusted many times... no luck.

 

[flyingscott]

What happens if you pump the fuel ball while that is happening?

 

[henryst]

What happens if you pump the fuel ball while that is happening?

Good question... sometimes that helps, sometimes it doesn't. I thought it was a fuel pump problem for a while, but switched out all hoses/tank with no change.