40 hp 1974 Johnson 2 cyl running rough low speed

[Howza]

40 hp Johnson 2 cyl 1974 elec start, Over all motor runs well at High speed, I do a lot of fishing and this past week when I troll for an hour or so I loose a cylinder and then it only runs on 1 cyl for the rest of my trip. It trys to kick in but fails. I pulled the plugs and the fowled plug is drenched. I replaced the plugs and did not have an issue of loosing a cylinder today but while trolling it sounds like it is cutting out (skipping) like it will eventually fail? Does this have anything to do with low speed idle or the Rich/lean knob? please advise.

Thanks Mark

 

[jasper60103]

Re: 40 hp 1974 Johnson 2 cyl running rough low speed

40 hp Johnson 2 cyl 1974 elec start, Over all motor runs well at High speed, I do a lot of fishing and this past week when I troll for an hour or so I loose a cylinder and then it only runs on 1 cyl for the rest of my trip. It trys to kick in but fails. I pulled the plugs and the fowled plug is drenched. I replaced the plugs and did not have an issue of loosing a cylinder today but while trolling it sounds like it is cutting out (skipping) like it will eventually fail? Does this have anything to do with low speed idle or the Rich/lean knob? please advise.

Thanks Mark

yea, you may want to review the carb adjustment procedure...

http://forums.iboats.com/showthread.php?t=167352

 

[DJ]

Re: 40 hp 1974 Johnson 2 cyl running rough low speed

40 hp Johnson 2 cyl 1974 elec start, Over all motor runs well at High speed, I do a lot of fishing and this past week when I troll for an hour or so I loose a cylinder and then it only runs on 1 cyl for the rest of my trip. It trys to kick in but fails. I pulled the plugs and the fowled plug is drenched. I replaced the plugs and did not have an issue of loosing a cylinder today but while trolling it sounds like it is cutting out (skipping) like it will eventually fail? Does this have anything to do with low speed idle or the Rich/lean knob? please advise.

Thanks Mark

It could, you may be running a litle rich/fat.

Firing a plug, with a high fuel load, (idle) takes more juice. Your coils may be suspect.

Inspect them for cracks, on the outer coating. If they are cracked, they will fail.