skip in my motor

Mymotorsucks12

Recruit
Joined
May 11, 2014
Messages
3
I'm hoping y'all can help me out with a problem I have with my motor. I have a mariner 40BE 2 cycle engine no idea what the year is I'm thinking somewhere during the 80's. Here's my problem, I don't know what to call it but I'm calling it a skip in the motor. When there is more than two people on the boat or a lot of gear the motor sounds like it is bogged down and when you accelerate it skips and sounds like it's running off only one cylinder. When I'm by myself on the boat my motor runs better and picks up running on both cylinders only skipping a little before it planes off. To me it sounds like one cylinder is robbing fuel from the other. But I thought it could be the coil pack so I took that out, saw there was a crack in it and tested the voltage and one side didn't was dead so I replaced it hoping my motor would finally work again and to my surprise it still does the same thing. So that lead me to break apart the carb but the carb was so clean it looked brand new. So my question is what else could it be? I hope someone here can figure it out so I can get back on the water! Thanks
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,938
Re: skip in my motor

Thats the Yammy branded motor and post entire model# as it sounds like its the points models and you have a set acting up....
 

Mymotorsucks12

Recruit
Joined
May 11, 2014
Messages
3
Re: skip in my motor

well i just tested the compression and i don't know much about compression but the bottom cylinder was reading around 100 psi and the top cylinder was reading the same thing but we kept pulling the crank cord and inched it up to about 102 psi. So that leads me to believe that the compression is fine not sure let me know what y'all think it could be
 
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