Mariner 60 4stroke midrange missfire

[gohagan]

I am in Ireland and have a twin engined R.I.B with a pair of 2001 mariner 60 4strokes fitted,The stbd engine has developed a missfire from about 2500rpm,I have swapped the carb bank over from the other engine thereby eliminating all possible other causes.The fault followed the offending carbs to the other engine. I have cleaned each individual carb,rebuilt,and synchronised the bank and tried the engine again on 2 occasions with no great success.Can any one offer any inspiration as to where on which carb the fault may lie? Thanks

 

[JB]

Re: Mariner 60 4stroke midrange missfire

Moving to Mariner troubles.

 

[BillP]

Re: Mariner 60 4stroke midrange missfire

Pull the plugs and see which is wet or looks different from the others. Sounds like a plugged jet to me.

 

[hondon]

Re: Mariner 60 4stroke midrange missfire

Those carbs are really difficult to clean completely.Your best bet is ultrasonic cleaning.No carb dips or you will cause more harm than good.

 

[gohagan]

Re: Mariner 60 4stroke midrange missfire

Thanks for the help. I swapped out the carbs till i found the offending one . Then after stripping down the unit found a very small jet which seemed to be blocked.I rebuilt the carb and installed the bank of carbs, synchronised them and all is now well!!!!!