1971 Evinrude SkiTwin carb Bowl

[ct1762@gmail.com]

Part # 312930 (electric start one with the choke solenoid mount). Float chamber / Bowl wanted. Servicing one of these motors for a long time customer. He's 82 years old, and stripped out the seized high speed needle by trying to drill it out.

Mod EDIT: remember iboats Forums don't have a swap, trade, used or for sale section

 

[racerone]

I do not believe the 33 was marketed in 1971.----If in Canada----evinrudeparts.ca-----might be able to help.

 

[ct1762@gmail.com]

it wasn't as a 33, but as a 40!. I believe the last year of the SkiTwin, and the 40hp variant (660cc for the 33hp, and 720cc for the 40hp). Honestly I didn't know a 40hp SkiTwin existed... just the lark/bigtwin 40's. Quite surprised. My part #'s are correct. unfortunately for us, the 33hp float chamber is different.

 

[racerone]

Well----- First year for the 33 was 1965 and 1970 was the last year for the 33 HP ( SkiTwin )-----The 40 changed from 71 to 76 , different block and different midsection.-----Left over 40 HP inventory was again marketed as a " commercial " motor in 84 and 85 I believe.----I do know these motors.

 

[ct1762@gmail.com]

Well----- First year for the 33 was 1965 and 1970 was the last year for the 33 HP ( SkiTwin )-----The 40 changed from 71 to 76 , different block and different midsection.-----Left over 40 HP inventory was again marketed as a " commercial " motor in 84 and 85 I believe.----I do know these motors.

sure but its a 40hp SkiTwin. Cowling and parts diagram shows this to be the case as well. I understand the block is different, but its still the old style with the 33hp version cowl/mid/gearcase. havent checked if the gears were beefed up for the larger block. Model 40153B.

 

[jimmbo]

In 71, the 40hp block that Evinrude and Johnson were using, was replaced with the Gale Division 40hp Block. Same Bore and Stroke, but different block. It didn't have the Thermostat controlled Cooling System, or the Midsection that E and J had been using since 1958, and returned to the Midsection that was almost identical to the 1957 35hp engine.

 

[ct1762@gmail.com]

i have heard of that Gale powerhead. good info thanks. but the midsection and gearcase look identical to my 66' 33 SkiTwin. Are you sure they are different?

 

[jimmbo]

I checked the part #s for the Exhaust Housing
1957 35hp 0377061 NLA
1966 33hp 0380500 NLA supersedes to Service Part # 0387535
1970 40hp 0384554 NLA supersedes to Service Part # 0387535
1974 40hp 0386488

While it looks like all the engines I checked had different Parts from the Factory, some do have the same Service Part as replacement. Does that mean the OEM ones were Identical, No. It means the Service Part will fit. Differences are likely to be contours. I do know the Exhaust Relief was different on the 57 35hp when compared to the 74 40hp. From more than 5 ft away, a lot of People would think they were the Same, but they weren't. Did the motor perform any differently if the parts were swapped? Not with the Model of Engine.
As for the Gear cases, to a lot of People they look the Same, however, again, over the years, there were occasionally Differences, inside and outside.

Just for your info, your 33hp, and the 1957 35hp, shared the same Bore and Stroke, and thus Displacement. However there were many differences in the powerhead, so they weren't the same engine, with a different HP rating.

 

[racerone]

Should be simple to find a carburetor bowl.-----Thousands were made !!

 

[jimmbo]

sure but its a 40hp SkiTwin. Cowling and parts diagram shows this to be the case as well. I understand the block is different, but its still the old style with the 33hp version cowl/mid/gearcase. havent checked if the gears were beefed up for the larger block. Model 40153B.

The 33 was the Ski Twin, some of the 40s were Big Twin, the others were Larks

 

[ct1762@gmail.com]

Never ran the motor so couldnt tell ya. got a really nice used carb for a Gale 40hp. Same block as Racer mentioned. This is the larger Gale block than the 33hp. Here are some pics. I have a 33hp SkiTwin at my shop so can compare side by side. Parts for the mid are identical (sure, the gearcase might have beefier gears/pinion for the 40 but rest of the part #s are the same). last pic is bad but its my 65' 33hp SkiTwin for comparison. Hard to see, but the first pic it says SkiTwin then "40" underneath. Block matches a SkiTwin 40hp model # as well. Really bizarre little guy but must be as light as a Tohatsu 40 twin, minus the top end power of course.

 

[ct1762@gmail.com]

The 33 was the Ski Twin, some of the 40s were Big Twin, the others were Larks View attachment 362420

thats what i thought! but no Also made a SkiTwin 40 in 1970/71'. 2 years only I believe.