carb upgraid

Asterope8

Cadet
Joined
Dec 1, 2013
Messages
28
I recently swap my carbs from the 90hp that were 1 3/16 and took the carbs off of a 140hp that are 1 5/16. Is this ok to do with out damaging the motor? I recently read that this is the way to gain more power.
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,589
Depends on what your wanting to do. If your trying to get it to put out 140hp the answer is no as it needs exhaust and port timing mod's. You might get 10-15 hp extra with correct jetting.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Your thinking is correct. The larger carbs will flow more air and fuel, making more hp. The 10-15 hp increase is a good guess. It is likely the jetting on the larger carbs may overfuel somewhat..you'll have to run it and do some testing. You will be happy with the results when you are all done. Why not put the 140 heads on as well?
 

Asterope8

Cadet
Joined
Dec 1, 2013
Messages
28
Thanks again you guys. Im going to try it out Friday. The 140 was on the boat but got water logged from a bad impeller. Im in the middle of getting the right parts and time to fix it correctly. Its in really bad shape. The pistons are all rusted. Anyways thats why I keep two motors around.
 

racerone

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Dec 28, 2013
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36,033
The 90 hp block may have smaller intake ports than the 140 hp block.
 

Faztbullet

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Mar 2, 2008
Messages
15,589
They exhaust is totally differnt as the 140 has a 'pot belly" exhaust and exhaust deflectors. Also the the exhaust ports are about .050 smaller...as for reeds they only need replaced if damaged. You might get close to 110 hp with bolt on parts....
 
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