johnson 150 gt

[mitmck]

i have an 86 mod 150 gt svo it cranks and runs good with muffs on in the driveway and at idle in the water. when you try to take off it just wont go. its acting like its bogging down or not getting any power. after i run it at a fast idle for a while about 10 or 15 mins it runs up to around 3300 rpm and no more. at that rpm its running at 53 mph and then the rest of the day it seems to run fine but never more than 3300 rpm. i fish alot in the winter so i need to make sure its not a temperature issue. please help.

[boats.net]

Probably need to remove and clean carbs, but do need to run a compression test.

[mitmck]

Probably need to remove and clean carbs, but do need to run a compression test.

what should the compression reading be.

[boats.net]

Should be even, no more than 15% difference in cylinders.

[mitmck]

ok i cleaned all the fuel system, the carbs,lines, filter and changed the spark plugs. took it out today still does the same runs sluggish for about ten or fifteen minutes and then something clicks on it and it takes off. is there a sensor or a switch on it like a temp switch that would cause this. once it starts running good it runs good all day. still the max rpm is around 3300 to 3500 rpm. it runs out at 52 mph.

[boats.net]

Need to see if have fire on all cylinders with a timing light.