Motor runs awsome except when I open it up!!

[MountainManMyke]

Hello, I bought a 1970 Mercury 80 hp last year and I had just used it for the first time this week because I was finishing my boat. I had started the motor up on the stand, idled it, revved it up and check to see if it went into forward and reverse..... everything ran perfect!! I put the motor on my boat and took it for its maiden spin and it turned out my motor wouldnt push the boat very fast at all. It would go about 1/4 throttle and would just stay there with no more speed. The primer ball doesn't get rock hard when I squeeze it many times but at the same time I dont see any gas leaking anywhere out of my fuel lines. Pls help with this guys... thanks

 

[Laddies]

Re: Motor runs awsome except when I open it up!!

Clean the carbs and fuel system to start with.