Force 120 must remove number 3 plug to start, will only idle

[cfryar]

Force 120 --Engine just tuned, on lake for first time. Could hear slight tinkling as engine running. Engine quit. Would not turn over. Through trial and error, only way to turn over was remove number 3 plug. Engine finally started but would only idle. If plug was inserted into engine, engine would die. Would die when you tried to put in gear. Finally got in gear and idled back to launch. Plenty of spark all cylindars. Stumped as to possible causes. Is this a power pack problem, excessive backpressure for some reason, other? thanks

 

[pnwboat]

Re: Force 120 must remove number 3 plug to start, will only idle

Remove all of the plugs. Take a look at the tops of all the pistons by turning the motor over by hand to bring the piston up close to the head and looking into the spark plug hole. See if #3 looks the same as the others.

Also a compression test may be helpful.

 

[moparman]

Re: Force 120 must remove number 3 plug to start, will only idle

do as pnwboat suggested, sounds like you may have lost a ring land and damaged a piston. post some pic's and some results of your inspection /compression check .

 

[cfryar]

Re: Force 120 must remove number 3 plug to start, will only idle

thanks for responses. Motor left at lake storeage. Will update in week or 2 when go back.

 

[cfryar]

Re: Force 120 must remove number 3 plug to start, will only idle

thanks for replies. motor at lake storage. Will review in next week or 2 with suggestions.