Merc 70hp Bogging

[mulliganmagic]

I have a 15'6" trihull K-Craft with a 1977 Mercury 70 hp on it. The powerhead is newer than the rest of the motor. I believe it is some where in the mid 80s. Well I took the boat to the lake today for the first time and found some problems. The motor doesn't like to idle very well unless I keep choking it. Then when I put it in gear it would die. The warm up leaver had no effect on how the motor would idle at all. Also, I managed to get the boat on plane a few times, but when I did I had to hold the choke in the entire time and it would bogg and almost die before it would go. Then I would have to hold the motor at wide open to keep it running. I believe that this is a carb problem. I'm not completly sure of this so if I am wrong please correct me. If it is a carb problem could I run some sea foam or similar product through it to clear the problem or would I have to disassemble them and clean them. Thank you in advance for the help.

 

[Bob H.]

Re: Merc 70hp Bogging

Best bet is to pull, clean, and adjust the carbs. That way you know what you've got. It sounds like the carbs are gummed up. You can try spraying the carbs, but for reliability you'd be better off cleaning thoroughly.