Different Carburetors on Twin Evinrude 150 or 175's - Mid 1980's

[BrettNC]

I have twin motors - 150 or 175's (flat back exhaust) - early to mid 1980's. Not exaclty sure.

One motor has 1 3/8" carbs, the other has 1 5/16" carbs. Is this right? They both seem to run well. Which size is right for these engines?

Also, do you jet for the motor or the size of the carb venturi/barrel?

 

[emdsapmgr]

Re: Different Carburetors on Twin Evinrude 150 or 175's - Mid 1980's

The 1 5/16" carbs were usually on the early XP/GT (high performance) 150's, standard on all the 175 flatback and all the 200 flatbacks. These engines were the 149 cubic inch blocks. They are great carbs for this engine. The 1 3/8" carbs were usually found on the 235 only-later years were 160 cubic inch displacement, however a some late XP/GT small bore 150's had them in the 88 or 89 timeframe. You will probably find different jets in the carbs. They are jetted by the factory to flow the fuel for the specific powerhead that has specific heads, timing advance, carbs, etc. You can find the factory jetting information direct from the specific Johnson/Evinrude engine parts lists that Bombardier has on the web: epc.brp.com

 

[BrettNC]

Re: Different Carburetors on Twin Evinrude 150 or 175's - Mid 1980's

Great information. Thanks emdsapmgr.

 

[emdsapmgr]

Re: Different Carburetors on Twin Evinrude 150 or 175's - Mid 1980's

I would check your engines for black plastic carb bowls. Later models had these bowls instead of the more expensive aluminum ones. The plastic ones have poor long-term structural rigidity and will warp with age. When they warp they cause carb fuel leaks at the flat gasket between the body and the bowl. Worse, they can leak air internally which can cause a lean condition when running. I'd replace them with the older bowls for peace of mind. Bombardier sells replacement bowl kits. FYI, the XP/GT 150 engines output somewhere around 165 hp.