# 1990 johnson gt 150 hp problems



## fishyeater (Apr 20, 2011)

I have bought a used 1990 Johnson gt 150 HP. Works well on the boat a lil rough on the start up but runs n starts. The problem I have is when I go to put boat on the trailer. I get up onto the trailer and I give it the throttle and it just dies, then it doesn't want to start up r idle after that at all forward r reverse any body got an answer for this issue??? Out on the water it runs very well it'll run my 21 ft starcraft 40 MPH no problems but as soon as I put it under a good load it just dies. I don't know were to start


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## squiddy (Oct 22, 2011)

not to familiar with that motor but when under load it stalls it would say fuel carb may be dirty will it troll at a slow speed it or it could be getting to much fuel or its just not firing properly and that would expain the not starting i would check the ignition system and the fuel but like i said not to familiar but i know my way around some wrenches if your near akron area call bridges marine he might be able to point you in the right direction if im wrong good luck


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## MassillonBuckeye (May 3, 2010)

Maybe the float setting or a stuck needle valve? Allowing it to flood when the motor is tilted. Are you trimming the motor up when you are trailering? Do you smell gas when this happens? Sometimes gas will pour out of the carb. Check that. Also if you are able, take a spark plug out and check to see if its wet when this happens.


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## fishyeater (Apr 20, 2011)

It runs good idles good I can troll all the way down to like 2 MPH. I think it has to do with the angle of the motor when boat sits on trailer. Next time I get out im ganna try n keep it level and see what happens. There is usually gas n oil floating around on top of the water so my guess is its gettn to much fuel at once (why im not sure) but think it's the angle of the motor letn fuel come out the carbs. I just had it down to my Mechanic before all this he said he put a new (the new style gasket) gasket under the power head motor has excellent spark good water pressure ( he reran the out hose back up and over the top of the motor to ensure that the water was pumping all the way up to the top of the motor) and changed the lower unit fluid. He also said he wanted to check it under a load but at that time I didn't have a prop on it. So I missed out on that part of it. But he said u have a very good motor. Ill get the boat out again and let u guys know how it goes. The fuel in it is Maybe a month old. When I first hooked fuel up to it and started it it fired right up but sounded doggy so I checked for spark 3 left cylinders were good the 3 right had no spark. So I took 1 plug out of the left side and rechecked the right side and only the middle cylinder was dead. So I bought 3 new coil packs and 9 new plugs but all the new stuff on. Now it doesn't have power under load. Has very lil delay when u go from idle to wide open runs very well. ??? Thanks for the info


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## MassillonBuckeye (May 3, 2010)

But how do you get it going 40mph if it dies under load? I'm confused. I thought the only problem was rough start and when trailering. Maybe try to make a video?


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