78 150 johnson will run at home but not on the lake please help

D

dozer25

Recruit
Joined
Apr 28, 2011
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I just purchased this boat and had it running at home on the muffs but when i put it in the lake at first wouldnt start. I rebuilt the carbs and replaced the spark plugs and now it will start and idle. I put it into gear and it will go until i give it throttle then it dies, but when its in gear I can play with the spark adv. arm and the linkage that goes from carb to carb and every once in awhile it will pick up and run great until i let go of both.
Any help would be greatly appreciated
 
HighTrim

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: 78 150 johnson will run at home but not on the lake please help

A linc n sync may be in order. Do you have a manual?

Have you also verified that she is sparking on all cylinders? Just because it runs on the muffs, doesnt necessarily mean it will run on the lake with backpressure on the exhaust as you've found. I would start with the basics, spark and compression. If the cylinders have adequate compression, and all cylinders will jump a 7/16" gap on spark tester, you can linc n sync the motor. The timer base and throttle plates have to move/open at precise times, or else she will fall flat on her face when accelerating.
 
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