150 Johnson looses power after warm up

[droutte]

My 1989 150HP Johnson starts up fine, idles good<br />and runs great for about 1/2 hour. I stop a couple times to fish and then try to get it up on plane and it boogs down like its not getting gas. The next time I take it out it does the same thing.<br /> I have recently changed plugs, power pack, timer base, stator and rebuilt carbs (but not for the above problem). It appears like something is failing after it gets hot.<br /><br />MOdel # J150STLCEM, 6 cyls.<br /><br />Thanks<br />Dan

 

[gsbodine]

Re: 150 Johnson looses power after warm up

I'm sure the mechanics will have plenty of advice for you, but your description sounds vaguely similar to a problem I was having with my 150 for a brief period. It turned out my fuel vent was clogged. One day when it was doing as you described I opened the gas cap and it immediately starting behaving better. I cleaned the vent and ...voila. <br /><br />Just a thought.

 

[droutte]

Re: 150 Johnson looses power after warm up

I have tried it with the gas cap off with no change, I have also pumped the primer bulb also with no change. Does not appear to be gas related.

 

[red10]

Re: 150 Johnson looses power after warm up

drouette, that may be a coil issue, being that old i would replace them , when they heat up the resistance gets higher and not a good spark