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idle/ low speed problem

S

Swenson514

New member
i have a 1994 Johnson 90hp v4 and the person that had it before me had the oil injection go out on them and that's all i know. now i mix the gas and all the oil injection stuff is either plugged of or disconnected. when you start the boat right away you have to let it idle at about 2 grand for like five minutes it seems or if you go to take off the motor will stall out on you. if you try to troll or drive slow the motor will also spit and die on you. when you put the throttle all the way open it studders a little then once up to speed runs like brand new. when you slow it down again to idle or troll speed it still runs good for about five minutes and then dies again. now when you go to start it you have to rev it up and let it idle high again for about five minutes before you can put it in gear again. i have rebuilt the carbs, put new plugs and wires, and i have also put new head gaskets in because i thought maybe water was leaking in or something causing it to stall out. any thoughts would be desperately appreciated. thanks
 
have you checked compression?will the spark jump 7/16 of an inch with a good snap?is this the same problem you had before you rebuilt carbs etc?l
 
Did you make sure the idle circuits were clear and blow them out w/100 psi air? How did you go about setting the carb mixture and what RPM is the idle set?
 
Oil injection failed ?-------------Time for a compression test.----Those motors are famous for broken piston rings.------When heads were off did you see any marks on top of pistons ?
 
racerone said:
Oil injection failed ?-------------Time for a compression test.----Those motors are famous for broken piston rings.------When heads were off did you see any marks on top of pistons ?
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i don't remember seeing any marks at all. are you thinking i just need to try new rings or wut
 
I have rebuilt more than one of these V-4 motors for worn out pistons / broken rings.-------------A compression tester is about $40.00 and I recommend you do this test first and foremost.------Once you establish good or bad compression you can make decisions as to what to do next !!!------Testing of the motor is the path forward !
 
You should be able to start your engine, allow it to warm up, lower your warm up lever to the run position and it should stay runnning without any help from you. And you should be able to shift into gear and it should idle about 700 -800 rpm's without dying out or spitting or sneezing It does sound like your motor could use some tweaking, however you need to go try this and pay close attention to a few things. 1. When you start your motor first thing and when you coming to a no wake zone and will have to idle " How do you have your motor trimmed? Is it trimmed all the way down? Keep your motor level when you're idling and in a no wake zone. Running trimmed down will cause an overly rich situation in most engines with carbs if you idle for extended periods of time.
 
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