1962 evinrude speeditwin help

[speediboat]

I have a 62 speed twin that has a carb on it with the hot water auto choke, I think the carb is from a 40hp, will it even run?

 

[F_R]

My guess is that it will run, but maybe poorly. People think that slapping a bigger carburetor on a motor will make it go faster. Sometimes it will, often times it won't.

 

[speediboat]

Should I look for the right carberator? My water tube is also broken right under the swadged portion.

 

[F_R]

Oog, water tube is listed as not available. Looks like you are needing a parts motor.

 

[oldboat1]

think I would opt for a 28 carb. Maybe compare the 18 carb to the 28, and see if that is an option.

 

[TN-25]

If you can't find a 28 carb (1962-64), I would think that a 33 carb from 1965-70 would be the next best thing.

 

[oldboat1]

^^good advice. 33hp carbs are probably pretty readily available.

 

[speediboat]

I own a metal lathe and I can make a swaging tool for the water tube. But if I could change the preset oriface in the carb bowl I might be able to fine tune it?

 

[F_R]

It is not a problem with the orifice. It is the size of the carb venturi, the big hole through the center. You will find that the 40hp is larger than the 28hp. The size has to match the CFM (Cubic Inches of air per Minute) according to the cylinder displacement of the motor. Too big a carb, not enough air flow, which means lower air speed at the venturi. And the air speed at the venturi is what makes it work in the first place.

The 33hp is a closer match if you have to go that route. But I still cannot predict the results.

EDIT: FYI, a 28hp is a 35.7 cubic inch motor A 33hp is 40.5 cubic inches, and a 40hp is 43.9 cubic inches.
And an 18 isn't even in the same family

 

[jimmbo]

a carb from a 1956 30hp might be close