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i think heat soak?
I have a 93 150 faststrike VJ150GLETG this a new to me its on a very mint 94 stratos 285 pro xl I purchased. I think I have the dreaded heak soak problem. today I was running motor for about 30mins 3-4k down river stopped to eat lunch 15ish mins later tried to fire back up and it wasnt so easy finally got it started then it idled like crap got it in gear and headed to the landing 5ish mins away. After I got to the landing the motor was idling terrible coughing and dying. Got it home 1-2hr later to check things and it ran fine in a drum so took it back out to a lake and ran great. this motor has 120psi per cylinder, new QL77JC4 plugs, CDI power pack,optical sensor, ive cleaned carbs replaced bowls done link/sink checked timing 4* at idle. It does have a electric fuel pump previous owner installed it, VRO fuel pump isnt any good. its at 3psi i checked that too. whats next??
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I have the same motor that had similar problems. I was able to reproduce the problem at home with the motor in a test tank. I found that it was sucking air around the throttle shaft of the starboard throttle body. Luckily it was still available new at a good price. Replaced and motor runs perfect. Mine would sneeze and cough like crazy after a heat soak, usually needing the enrichment circuit pushed constantly. If you can reproduce the problem, use toothpicks to block the idle jets one at a time seeing if it helps or hurts. Spraying carb cleaner around various areas may help find any air leaks.
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Ohh boy that’s sounds terrible I know these parts are getting scarce. I have to carry some toothpicks with me and try it next time.
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So which jets are the idle jets? Top or bottom
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I think it’s the bottom one of the two. You may also be able to cover the carburetor throat with couple of fingers to act as a choke to pinpoint the offending cylinder.
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Ran it today in a drum for 15-20mins at idle. Ran great no problems, I did stick the tooth picks in the bottom holes and with every pick I installed it would run richer and richer so I don’t think I have an air leak. Would be nice to find different orifices to rich up the idle mixture like I read about.
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Maybe it just needs to be used some. Rough running could be too rich. Sneezing and coughing is more likely lean. Next time it acts up push in on the key and see how it responds.
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I did that and it helped. ive been reading all day about this heak soak problem problem 50posts and it seems like everyone has the issue but no one posts what fixed it. I found orifice jets so thinking about getting some and trying. also i have the black intake gaskets ive read where they need replacing to the redish/brown ones but cant find out why.
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SC Club Moderator
Ethanol in the fuel is the reason, same with the float bowl gaskets, they used to be black and are now ethanol resistant brown.
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So better gas is the first thing. what else can I do to help prevent this? ive read about going smaller on the idle orifice on here a few times i have 43s
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Check the operating temperature and make sure it’s not getting too hot. I don’t know what normal temperatures should be, you’ll have to search for that. If you do a carburetor rebuild, make sure to check all the passages. I had one clogged for the idle circuit that caused it to sneeze and cough.
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SC Club Moderator
143* F is the operating temp a failing vapor pump can also cause this. #43 are what is called for. pushing on the key to give the engine an extra shot of cool fuel helps as does pumping the primer bulb will help.
Last edited by ChampioNman; 05-13-2024 at 09:29 AM.
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I’ll get some flak for this. But it has an electric fuel pump the vro pump died previous owner added the electric pump. Everything is there still he just has the pump in where primer bulb was. Vac port is broken off bottom of pump too the vac hose from motor is plugged at bottom of engine. I did check pressure it’s 3lbs