1999 Johnson 115 misses at high speed

[rthomp]

Engine has not been run since last fall. Started to miss after I put it in this year. I changed the plugs but did not help. Engine might run fine for 5 minutes and then starts misfiring. Any Suggestions?

Thanks for your help.

 

[boobie]

Re: 1999 Johnson 115 misses at high speed

Do a cyl drop test on it and see if you can nail it down to any one or two cyls. You can also use a timing light on it and look for any black spots when it misfires.

 

[rthomp]

Re: 1999 Johnson 115 misses at high speed

Thanks Boobie, I'll try this when I get it back home. The wierd thing about this is it only does this at full throttle. I can pull the thottle back and it runs fine. It idles fine also. I checked the fuel lines and the filter and they seem to be good also.

 

[boobie]

Re: 1999 Johnson 115 misses at high speed

An ignition miss will act up at wot. Seen it many times.