150 Johnson rpm problems

[180 fourwinns]

I have a 2000 150 Johnson that was running great last summer and then just crapped out one day. I changed and gapped the plugs, checked compression (all good), bought one new coil pack and swapped it with all 3 one at a time and no change. I also replaced the little plastic zip ties on the fuel lines with proper hose clamps. I am now looking towards fuel/air problems as it is hard to keep idling on hot summer days. The power is just not there anymore, the rpm has dropped off a couple hundred. Need help!!

 

[Reel Appeal]

Re: 150 Johnson rpm problems

180 fourwinns,<br /><br />Maybe one of the carbs is fouled with gunk.Fuel delivery problem.When you changed the plugs did you notice any difference in dry/wet or coloration?You may want to check spark as well.Do you have a service manual for your motor?

 

[clanton]

Re: 150 Johnson rpm problems

Check the float bowls for trash. Check timing sensor. If you replaced the plastic zip ties with metal clamps,and tighten to much, it breaks the plastic nipples, and causes fuel/air leaks.

 

[180 fourwinns]

Re: 150 Johnson rpm problems

All the plugs are the same colour and all or wet. I do not have a manual unfortunately?! I only purchased this boat/motor last spring. Before this happened the powerband was unbeleivable. The fuel filter looks pretty good.

 

[180 fourwinns]

Re: 150 Johnson rpm problems

Where is the timing sensor? I thought that this might be a timming problem origanly.

 

[Solittle]

Re: 150 Johnson rpm problems

You could keep trying this & that or wait until you get your manual and follow the troubleshooting procedure.

 

[180 fourwinns]

Re: 150 Johnson rpm problems

Thanks for the help. I will certainly be getting a manual this week. Cheers.