johnson 70 ,lots of fuel problems

[mike cuyk]

Ihave an apprx 1983 70, and just recently started having fuel problems,(wont idle, new fuel bulb not staying hard after pumping boat most of time refuses to run full speed...) I have replaced all plugs, all fuel lines changed fuel, had carbs cleaned took apart pump and checked(everything looked ok in it) but it just doesn't want to run full speed and will "lunge" or speed up then die. I have run out of ideas. Do I just need to put kit in pump or does it sound like i'm just sucking air in from some where??

 

[noelm]

Re: johnson 70 ,lots of fuel problems

OK, If I read it correctly, the fuel bulb does not stay hard, correct? then if this is so, the problem lies between the bulb and the tank vent, not the Motor side (more than likely anyway) make sure your tank vent is clear, like remove the filler cap, check for a kink/hole in the fuel line to the tank and get back to us.

 

[mike cuyk]

Re: johnson 70 ,lots of fuel problems

Thank you for your reply, I just took boat out again and right now it will not hold a hard primer ball, I have had the boat one year and the ball and hose "looks" new. But it still will not stay under pressure, .Vent in cap seems to be working ok and I even tried running with the gas cap loose so I know it was getting air. What I don't understand is even when I pump the ball and it gets hard for a while the boat speed still is kinda slow. How can i check the primer ball or valves to see if their good. Right now the motor seems to run smooth just does not hold prime and goes slower then it used to. thanks again! this forum is great!!!!!

 

[tashasdaddy]

Re: johnson 70 ,lots of fuel problems

did you use rebuild kits when you did the carbs, and pump? did you do all this when you did your carbs? do not mix parts, and mark the center carb as it is different than the top and bottom carb. sounds like you still have clogged jets in the carbs. have you done a link n sinc. this sets the carbs, and spark to where they work properly together.

 

[mike cuyk]

Re: johnson 70 ,lots of fuel problems

I had a boat mechanic just clean carbs and he said everything looked fine on them. I did mark carbs so they were put back in right order. I'm not sure what a linc and sync is, All i did to pump was take screws apart and look at it, everything look good but I'm not an expert so I made have missed something. What is that "valve" on the side with the red lever and shrader air valve for and could it be causing boat to run smooth but slow? Should I just by a rebuild kit for pump? What all could cause me to loose prime while its running? ( motor still runs smooth even with out prime ball being hard) should I just put rebuild kit in ?

thanks