low revs only running on two

[oilman321]

1988 johnson 60hp vro....have sorted the starting when warm problem...now when started only runs on two cylinders...top cylinder not firing...(pulled plug lead off when running and no difference at all)only runs on two cylinders at low revs but when put in gear and given some throttle third cylinder cuts in and engine runs perfectly....have swapped leads and still top cylinder which wont fire, also new plug but still no difference....help please

 

[Cricket Too]

Re: low revs only running on two

oilman....sound like the top carb may have a clogged idle circuit. When you get to a certain rpm you start to use the high speed jet and get the fuel that the cylinder needs. Clean that and the rest of the carbs while your at it, get a rebuild kit and you should be alright. Check to see if you are getting spark to the plug by pulling the wire and using a spark tester or use a screwdriver and ground it to the block to see if you are getting a spark(7/16"). By just pulling the wire you are not isolating fuel or spark. My guess it is fuel related. Good luck.