1999 Johnson Problem

[Juandizzie]

Hi guys I have a 15ft whaler (late 80's model) with a 1999-2001 Johnson, I seem to be getting a problem with this engine one day it will run great the next it will start perfect and then wont rev past 3000rpm at full throttle. I had a mechanic look at it and he advised that it was a carb related problem and suggest they rebuilt this was done, the engine worked fine twice after that but today the same problem yet has occurred. I turned off the next day had the mechnic come by and check the problem engine worked perfect. Points i noticed, it only does this on a longer trip on the trailer the water and it idles a bit high to me 1000rpm? Thanks for any help

[Juandizzie]

Also the VRO is disconnected i mix oil and gas in the tank

[boats.net]

When the motor is acting up, check for spark. If spark is good, spray silicone spray through the throat of each carb, note the motors reaction. One shot per cylinder, either it will pick-up or die out. If it picks up, you are having fuel problems in that cylinder, if it dies out that cylinder is working.

[Juandizzie]

Thanks for your response, last time this happened we were getting spark whats interesting to note. We took off the middle lead engine died, restarted took off the top first then the bottom lead engine did not die? Im a newbie to this so im not sure what should happen here. Is it possible that a float in the carb maybe sticking?

[Juandizzie]

Hello,

I did what you advised here is what was noted, Lower carb idled lower but didnt cut out, middle carb cut out and top carb did the same as lower carb.

[boats.net]

stuck float (if closed could cause no idle change) if stuck open will over flow. Complete a compression test, also try shooting silicone spray through the throat of the carburetors one at a time, if it dies carb is working, if it picks up carb is not supplying fuel, if nothing happens problem not likely fuel.