Johnson 35 (1999 model) intermittent problem

I have a 35 Johnson (1999 Model), three cylinder, VRO, purchased new. Motor ran great for first three years, but has been erratic since. Trouble first began when motor would kill suddenly when running at near full throttle. Motor would restart and then run fine. As time passed, these episodes increased in frequency and the motor would become harder and harder to keep running, finally running -- if at all -- only at idle speed. Any attempt to throttle up would result in the motor killing, sometimes emitting a puff of smoke.

The trouble is, the problem is intermittent. The motor will run perfectly one day, and act up the next. I've had it in the shop three times, and each time the motor runs perfectly. The shop has replaced fuel filters, plugs, gas tank and hose, checked the carbs, and everything checks out. Plugs never foul up, and the motor never even misses on its good days.

Some possible clues?
. Trouble often begins after stopping and starting a few times while fishing.
. After sitting overnight, the motor often starts and runs fine -- as though some internal sensor had reset.
. After winter storage, when the motor would not start at all, the mechanic found oil in the carbs. Upon draining the carbs, the motor started on the first pull.

After the latest episode, I mixed oil with the gas and the motor ran fine, though I am far from confident that this good behaviour will continue.

Any advice?

Lars

Re: Johnson 35 (1999 model) intermittent problem

its possible you found the problem the vro if your not getting enough oil it will shut down try just pre mixing 50:1 if it runs good your all set

Re: Johnson 35 (1999 model) intermittent problem

Hello i've got a 1996 35hp johnson with similar problems, I've checked everything out on mine and so far the advise i've had on this site is either the CDI pack is playing up, or the engine is running too rich which mine seams to be to as the throttle gets advanced it just floods the engine due to not enough air. I have by passed my oil mixing unit and am running oil from the tank, its running better at idle but still cutting out when i advance the throttle. If you find out whats up post it here!

Re: Johnson 35 (1999 model) intermittent problem

dave , if flooding due to not enough air, suggest you check you float needle not sealing, the increased pressure of the higher revs, could be pushing the needle open, and flooding the motor, also link n sinc. are you sure it is flooding, and not starving for gas, like dirty high speed jets, have they been removed and cleaned?


bgbass, if you ran the engine dry when winterizing, the oil pump keeps pumping oil into the carb, even thought the fuel line is disconnected, the probable reason for oil in the carbs.

Re: Johnson 35 (1999 model) intermittent problem

your right it would didnt think about that just took it for granted that vro was disabled when winterized thats what i do when i do customers engine sorry.

Re: Johnson 35 (1999 model) intermittent problem

Thanks for the advice, guys. The motor is in storage now for the winter and I'll try it again in the spring. Hope that pre-mixing the gas solves the problem. Also, I have never cleaned or rebuilt the carbs, though the mechanic who checked them claimed the carbs checked out OK. When the motor is working normally -- about half the time -- it runs fine at both low and high speeds without missing. Could it be an intermittent problem in the electronics?

Dlaurs