88 , 150GT Johnson

rogerd8

Seaman Apprentice
Joined
Jan 5, 2003
Messages
30
Got a question here guys this motor runs real rich and was thinking maybe one of the carbs is fouling out . at times it will run fine at WOT but then at times can't get into WOT but smells raw fuel not bruning ,,, any Ideals help me out here.
 

rogerd8

Seaman Apprentice
Joined
Jan 5, 2003
Messages
30
Re: 88 , 150GT Johnson

Thanks for the reply there ,, next would the carbs fit off of a 175 HP ,,they are rebuilt and ready to use
 

rogerd8

Seaman Apprentice
Joined
Jan 5, 2003
Messages
30
Re: 88 , 150GT Johnson

Thanks for the reply there ,, next would the carbs fit off of a 175 HP ,,they are rebuilt and ready to use
 

jim dozier

Lieutenant Commander
Joined
Jan 8, 2003
Messages
1,970
Re: 88 , 150GT Johnson

Don't know about the other carbs, somebody else will probably know and chime in.
 

clevecan

Petty Officer 2nd Class
Joined
Aug 25, 2008
Messages
130
Re: 88 , 150GT Johnson

I may be wrong, But I think the GT150's have 175 carbs
 

jonesg

Admiral
Joined
Feb 22, 2008
Messages
7,198
Re: 88 , 150GT Johnson

Float is sticking open. Rebuild carbs.

Jim that could be correct, or wrong.
Its also likely its dropping a cyl due to ignition than flooding out.
A timing light will show which.
Also , hold the back of your hand 1 inch from the carb throat, if it gets wet with fuel spray its flooding.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 88 , 150GT Johnson

Check the serial number on the top of the powerhead. The high performance 150's (GT/XP) were all stamped 150S on that top casting plug. The S in the serial number indicates that it is a GT/XP model which comes with the larger-throated 175/(early 200) carbs. You should see 1 5/16" throated carbs on that engine. The carbs have their size cast into the front lip of each carb. That S model engine will make 10% over a normal 150 hp from the factory, or nearly 165 hp. Won't help to jet those carbs up even more, unless you change heads, port it, etc. I'd follow up on Jonesg's comment and check the spark.
 
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