1985 Johnson 90hp carb question

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emeraldcozy

Cadet
Joined
Oct 11, 2005
Messages
13
I have 1985 90hp Johnson and need to do a carb job on it. I`ve heard that the only difference beween a 90hp and a 115hp were the carbs. So here ismy question. Could I purchase a set of carbs that came of a 115hp and put them on my 90hp ? If so how difficult is it to rebuild the carbs ? Any advice would be greatly appreciated.

Thanks, Markus
 
W

wavrider

Chief Petty Officer
Joined
Nov 26, 2007
Messages
543
Re: 1985 Johnson 90hp carb question

I have a 1978 115hp johnson with 90 carbs on it according to the part nimber on the carbs.

After researching the difference in the carbs it appears only that the jet sizes are different.

BRP site has the IPB of both carbs to compare them with part numbers also.
If youy are gong to rebuild the carbs then just order the bigger jets for the rebuild but it may give you to rich a running mixture at top end.
 
Chinewalker

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
Re: 1985 Johnson 90hp carb question

There are other differences than the carbs. Bigger carbs generally don't translate to bigger performance unless other things are taken into consideration. A 115hp has the 140hp porting with the 90hp style exhaust (often referred to as a flat-back). Your 90hp has smaller intake and exhaust ports and wouldn't be able to fully take advantage of the 115 carbs. With proper re-jetting of the larger carbs you may achieve some performance gain, but if you simply drop 115 carbs on there the motor will probably run poorly and use a lot more fuel...
- Scott
 
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