merc wont idle and come up to full rpm under load

[ekern68]

i've got a 1973 Merc 40 Hp. last year ran like a champ and would idle all day. This year just the opposite. Wont idle and only comes up to about 50% on RPM when in the lake. At home with the earmuffs on it accelerates perfectly (but still wont idle). Dont think varnish is an issue, ran it out of gas to store it. the only thing i did this year was mix some sea foam with the gas on the first trip to lake. sprayed the carb with sea foam deep creep while it was running today but didnt fix anything. Any ideas. what a sucky time of year for boat trouble

 

[62larkowner]

Re: merc wont idle and come up to full rpm under load

check compression and spark, ( muffs = no load ,lake = load) as far as idle, not sure