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88 Johnson


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06-28-04, 06:54 PM   #1  
david h
88 Johnson

I just purchased a 15' sunbird, 83 model with a 90 hp (88) Johnson. This boat does not go as fast as I thought it would and I have many questions. I assume you want one question per thread so here it goes. The boat runs fine at high speed but is a little rough in idle. Sometimes it cuts off if I decelerate too fast ( fast to neutral). I could not find an idle screw to idle it up a little. But the weird thing is if I adjust the trim while idling to a certain position it almost always cuts off. I can't figure this out. Any suggestions?
I have a few more questions as well, let me know if it is ok to post several on on thread.

 
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06-29-04, 06:48 AM   #2  
Hello: David H. Welcome to the Boats, Sailing, Pwc's & Navaigations topic and the Do-It-Yourself Web Site.

As long as your questions pertain to this specific boat and it's engine, you can ask as many questions about it all in this one topic. Simply continue to use the reply button. Keeping all the questions in one thread helps everyone reading and replying to more easily follow along.

Engine stalling is almost always an engine problem. Most likely related to carburetor(s) or fuel injection system. May also be a fuel supply condition at lower speeds. May also have an engine timing problem, etc.

Boat speed also has several factors which effect it. Prop size and pitch is the most likely. The current prop is not likely to be the original. Also, the boat is an 1983 and the engine is a 1988.

Which means the original engine was replaced and the current engine may not be a perfect match to the boat or your intended usage. A boat shop and or boat dealer can help determine which prop is correct for the intended usage and that specific engine, etc.

Trim places different loads on the prop as does all other factors. Each effects the engine. The condition you describe is likely related to the engines tuning, carb and prop.

Best place to start is checking the cables for proper adjustment and than with a carb internal cleaning. Most likely the carbs internal jets and fuel passages for the low speed fuel circuit are slightly restricted.

Attemtping to adjust any fuel screws or fuel adjustment settings will only mask a problem. Not correct it. Same applies to engine timing. May need to have either or both serviced professionally, if unable to do it yourself.

Use the reply button to add additional information or questions to this thread. Using this method keeps the topic back up to the top automatically.

Regards, Good Luck & Safe Boating. Life Long Boating, Fishing and Navigation Enthusiast. Web Site Host, Forums Monitor & Multiple Topics Moderator.

Regards, Good Luck & Safe Boating. Sharp Advice.
Web Site Host, Forums Monitor & Multiple Topics Moderator.

 
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06-30-04, 05:19 AM   #3  
david h
Thanks for the reply, we changed gas tanks and that helped a lot. Maybe the fuel pick up was bad. Also we used fresh gas. I had a guy adjust the linkage a bit for me and it picked up some speed then. I wasn't getting full throdle. Seems to be doing fine.
I am sorry I wasn't specific about the motor. It is a model (88), 1983, 90HP. I was told this motor is a high torque motor, and I wouldn't get the speed as other 90 HP motors.
I am running a 17 pitch prop and mat try a 19 pitch if that would increase speed?
Also I am considering removing the whale tail to help also.
I was told to use a wedge behind the motor so I can get more trim to increase performance. Will this help?

 
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