1990 20hp johnson sneezes and dies

[chriscamp612]

I have a 1990 20hp johnson, this year I put in a new water pump kit, prop, Spark plugs and wires. New fuel tank and lines with new pump bulb and a in line fuel filter and was confident my boat was ready to go. The motor Idled rough and ran sluggish. Then I took off the carb and had a Johnson tech rebuild it with no change, a rough idle a sneeze and it dies. I took the boat to the same Johnson boat place and they changed the ignition module, fuel pump, rebuilt primer pump, changed the head gasket, intake gasket and the left side exhaust and water gaskets and still no change. Thay adjusted the timing and carb sync and had other techs go through the carb 3 more times incase he missed anything, still no change it runs the same. I got the boat back home and I was messing with it and a car tech heard it spitting and sputtering, he walked over and blocked most of the incomming air flow to the carb and it purred like it was brand new, took his hand off to allow full air flow to the carb and it choked and died. Does the carb just need to be replaced or did I just take it to the wrong place?

 

[tashasdaddy]

Re: 1990 20hp johnson sneezes and dies

99% clogged low speed jet, not enough fuel getting thru. see carb cleaning in the TOP SECRET FILE, > http://forums.iboats.com/showthread.php?t=299680

 

[crxess]

Re: 1990 20hp johnson sneezes and dies

Check everything in your fuel delivery system. Up to and including the fuel tank. You are getting low fuel flow. Any blocked valve, weak pump, air leak, crack in a line/fuel fitting can cause this.
Could be sucking air somewhere.

 

[tmcalavy]

Re: 1990 20hp johnson sneezes and dies

Sounds like you need to clean the carb, or have it done in a good shop...I wouldn't go back to the shop that did all that work and couldn't solve the problem...just my .02 cents.

 

[chriscamp612]

Re: 1990 20hp johnson sneezes and dies

The only good thing about that marine shop is that because they could not fix it, they charged me only for the parts and no labor. But they got the boat so it could be fixed, so it has been agrivating.

 

[wideide]

Re: 1990 20hp johnson sneezes and dies

I had simialer problems check youre hoses and try spraying carb cleaner around intake and leaf plate gasket when it running if it dies replace intake and leaf plate gaskets fixed my problem mite work for you. good luck