1986 85 hp back fires

[NH badboy1166]

I have a a 85 hp force.When I start it up (only cold starts) it backfires a couple times then it runs nice at idle & starts right up when warm.Put it in gear & she stalls unless i throttle fast to get rpms up,, also bringing up rpms in the water it sounds like its not running on all 3 cyls but full throttle it sounds strong & good.Anyone know what is causing the backfire ?can this be a simple carb syncronize??It has new plugs & the fuel screen was clean. Any suggestions I am open to ..Thanks

 

[john from md]

Re: 1986 85 hp back fires

Backfiring through the intake of a two cycle engine, barring mechanical damage, usually happens because the mixture is lean. Check your choke plates to see if they are closing all the way. I'm assuming that you have the trottle in fast idle when this is happening.

Also, when was the last time your carbs were cleaned and adjusted? If you can't remember or don't know, it is time to do it.

John

 

[foodfisher]

Re: 1986 85 hp back fires

FYI backfiring can tear the fuel pump diaphram.