Anyone found a solution for Johnson heat soaking issue.

[Trenthonda1]

I have a 98 Johnson Faststrike 150 just had the motor completely rebuilt with the carbs rebuilt and new water pump.
I had the heat soaking issue before the rebuild. But the boat runs great right off the trailer but after the engine gets warm and you kill the engine and fish for awhile the motor stalls when accelerating. Boat cranks and ildes fine but any advance in the throttle and the engine dies. If you feather the coke while accelerating it accelerates fine. Im pretty positive it's a the issue of heat soaking where the fuel in the carbs and lines evaporates while the engine is switched off. I read forum after forum and haven't got an 100% fix for this issue. Ive herd try removing the thermostats causing the engine to run cooler also herd replacing vro pump, vapor pump... etc. Has anyone found a fix for the issue? I know this is a common issue with these year engines but there's gotta be an resolution for this issue. Thanks in advance!

[StratosDadRI]

1998 u should have ide mixture screws, give them all 1 full turn out. if its a little better go another 1/2-3/4

[omcforever]

Never ever remove the thermostats in a 2 cycle recreational boat motor and I don't think replacing a working VRO pump will solve anything . You can go to 100 forums and get 100 different solutions. Follow what the guys here that specialize on that motor recommend.

[Trenthonda1]

1998 u should have ide mixture screws, give them all 1 full turn out. if its a little better go another 1/2-3/4

How many idle screws are there? And where exactly are they located?

[316jughead]

Welcome to the forum. The so called "heat soak" has been solved here many times. Run non ethanol fuel if you can. Do a search here on ChampioNmans posts and on 316jugheads posts. You will find the correct answers to your questions. StratosDadRI also. If you still need more help just let us know.

[StratosDadRI]

How many idle screws are there? And where exactly are they located?

6 ,, 1 for each carb and looking at them they are behind a access hole.

[StratosDadRI]

green is mid range air bleed, Red is idle and adjustable, blue is main jet behind bowl drain screww

[blockzilla]

1998 u should have ide mixture screws, give them all 1 full turn out. if its a little better go another 1/2-3/4

I had the same issues, ended up with my screws all 6 turns out before it got better...

[redbeard55]

i have a 98 175 f/s ran good off the trailer until i stopped an fished then, trying to go again would be an adventure, spitting cutting off an flooding out if i choked it.. i went five sizes lower on the air orifices recomended by omc rep. marked in green above. Solved my problem, try putting tooth picks in air orifices to block air when problem occours DO NOT BREAK THEM OFF just block the air to carb, if it smoothes it out you have the same symptions i had an 5 sizes lower air orifices fixed my issue, smooth as silk ever since

[redbeard55]

My motor is a 98 J175GLECD some models may have different jets on their carbs,

[headhigh]

My unprofessional opinion...FWIW.

You say you can "feather" the choke a couple times while trying to accelerate and this fixes your problem. What I get from that bit of information is that your timing may be advancing BEFORE the carbs open and start providing adequate fuel...thus, the choke helps your condition. You might need to back your cam roller off just a bit and allow those carbs a little more time to start opening before your timing advances. Timing advance and carbs opening should happen at the exact same time.

The pro's (Fred, Jerry...) should be able to provide a little more insight. At the very least, I would try that before I looked at replacing orifices.

[185er]

i have a 98 175 f/s ran good off the trailer until i stopped an fished then, trying to go again would be an adventure, spitting cutting off an flooding out if i choked it.. i went five sizes lower on the air orifices recomended by omc rep. marked in green above. Solved my problem, try putting tooth picks in air orifices to block air when problem occours DO NOT BREAK THEM OFF just block the air to carb, if it smoothes it out you have the same symptions i had an 5 sizes lower air orifices fixed my issue, smooth as silk ever since

this correct mine along with stopped using seafoam as a fuel additive and good fuel. no problems since.

[redbeard55]

If timing was an issue the motor would act up from the get go, not saying that roller timing does not need to be tunned, he can try the tooth picks before buying the air jets, they are about 9$ each from boats.net omc product, i know i battled the aggrivating problem for months an some of these dealers will sell you pumps, staters, p/p and rebuild your carbs an you still got the same problem, those carbs were set up for 1998 fuel. hopfully we can give him enough things to try to fix em up.

[D Wood]

Know this is an old thread.....I've been fighting heat soak for year's, off and on.... time of year/ temps......so finally did the vapor separator/pump rebuild and they started selling pure fuel near me no more 10% crap. Cleaned out fuel tank etc. No more stabil or other additives, just fuel and oil.... No more heat soak Has never ran so good. 1994 Johnson Fast Strike 150.
J150GLERA. Thanks all for the info on all the heat soak threads.

[Bassmeister]

Two things you can do until you get it fixed, when shutting down to fish idle for a bit to fill the bowls with fresh fuel, or pump the bulb before you crank up and take off. Many posts here about heat soak, do a search. One of the best things is running good fuel if you can find it.

[316jughead]

Know this is an old thread.....I've been fighting heat soak for year's, off and on.... time of year/ temps......so finally did the vapor separator/pump rebuild and they started selling pure fuel near me no more 10% crap. Cleaned out fuel tank etc. No more stabil or other additives, just fuel and oil.... No more heat soak Has never ran so good. 1994 Johnson Fast Strike 150.
J150GLERA. Thanks all for the info on all the heat soak threads.

The VST and pump is the most overlooked component in these fuel systems and maybe one of the most important. It's the pump diaphragm and a leaking VST tank gasket that's the problem. The vapor must be pumped out or the whole thing doesn't work. The number one thing is use non ethanol fuel if you can get it. I know how you feel, very happy, good job.

[Toby1]

My 90 how Johnson has done this the last 3 fishing trips. I have changed the plugs and primer bulb, still doing the same thing, it coincided with me filling the gas tank and putting in gas treatment, and filling the oil tank, could any of that cause heat soak? I'm afraid to take my son fishing because I am scared it won't make it back

[ChampioNman]

My 90 how Johnson has done this the last 3 fishing trips. I have changed the plugs and primer bulb, still doing the same thing, it coincided with me filling the gas tank and putting in gas treatment, and filling the oil tank, could any of that cause heat soak? I'm afraid to take my son fishing because I am scared it won't make it back

Model number?

[Toby1]

[QUOTE=ChampioNman;9484211 Model number?[/QUOTE]
Sorry- model number- J90GLSTA -SER.NO - 05034894

[ChampioNman]

Start with the vapor pump and a rebuild of the vapor tank and gasket replacement. Inspect your carbs for fuel leaking out of the carb bowls, a cracked maintenance valve on the primer solenoid a good over all inspection of the carbs.