40 HP Johnson Problems still

[Briand3096]

Ok I have a 1986 Johnson 40HP. Bought the boat in NONE running shape. When checking it out I noticed no fuel. Started with new fuel pump. Then it ran only with choke on. I removed the carbs cleaned them and rebuilt them. I soaked them and took everthing out when soaking. I also noticed on the lower cylinder the plug wire was bad. I bought a new wire set and plugs. The motor runs allot better now but still not ideling. I retested the wires again and the same wire is bad and this is the new one. Can something cause a wire to fail? This dam motor is doing my head in now. Any help please.
Thanks, Brian

 

[tashasdaddy]

Re: 40 HP Johnson Problems still

is it the wire that is failing or the coil the wire is attached to? swap the coil positions and see if the problem follows the coil. did you do a compression test? did you replace fuel lines carbs to tank, with alcohol resistant fuel lines?

 

[Briand3096]

Re: 40 HP Johnson Problems still

Yes all new lines,hose,pump and tank. Both carbs rebuilt. It is just a spark plug wire. When I first bought it one plug wire was bad so I replaced both with new ones. After going over all the fuel problems I started to recheck spark and found the new wire to be bad on the same cylinder. The motor now runs much better but still can't lower choke lever all the way without it stalling out. It just may need some fine tuning now. Timing and idle settings.
Thanks, Brian

 

[Daviet]

Re: 40 HP Johnson Problems still

If you have to run with the choke on it indicates that the low speed circut in the carb is not working properly. Do you have two copper tubes, one inside the other attached to the carb body extending into the bowel? If so make sure the passages are clean. Look on the back side of throttle plate, there should be some tiny holes in carb body, make sure they are clean. Do you have a strong blue spark on both cylinders?