1994 Johnson 90HP V4 - Is this really and air leak?

kenpars

Cadet
Joined
Jul 8, 2003
Messages
8
Hello everyone,<br /><br />I wrote in a few weeks ago regarding this boat. At the time I had a problem with low power. I think I solved that problem by making sure that all 4 coils were properly grounded to the block. Now the problem is that ever since then the engine has been idling very fast (3000+ rpm) when in the driveway with the earmuffs on. I have now taken the carbs off 3 times to inspect and I am sure that there are no carb-related air leaks. I have also cleaned all the jets on the carb. They are all original jets and have not been changed out since the boat was running properly.<br /><br />I have tried adjusting the idle speed stop on the throttle arm linkage, but this has no affect on the carb throttle plates since there is already a gap between the throttle cam and the carb roller. The carb throttle plates are definately closed and centered in the barrel. I guess my question is where do I check next? Will the RPMs go down when the boat is actually in the water and the exhaust has the extra backpressure?<br /><br />Any help is very much appreciated. My wife thinks this boat is a money pit and will never run right.
 

ob

Admiral
Joined
Aug 16, 2002
Messages
6,992
Re: 1994 Johnson 90HP V4 - Is this really and air leak?

Are the carb flaps indeed closed fully? If so your engine may have its timing advanced way off mark.Does the timer plate move freely from stop to stop when the throttle is operated?Insure that the timer plate return spring is secure on its plastic post.
 

kenpars

Cadet
Joined
Jul 8, 2003
Messages
8
Re: 1994 Johnson 90HP V4 - Is this really and air leak?

OB,<br /><br />Thanks for the reply.<br /><br />I have watched the timing ring rotate and it appears to be fine. I don't remember seeing the return spring plastic post, so I will look at that tonight. I have tried adjusting the throttle / timing arm stop screw to both extremes of its motion without any affect on the speed.<br /><br />One other observation is that the motor has become hard to start and actually tries to turn backwards sometimes when the starter is turning it. Ususally right before if finally starts and revs out of control. Maybe there is something to the timing being too advanced.
 
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