Does 1971 Johnson 40 have a thermostat?

[kaneerarchery]

This diagram of my 1971 Johnson 40 does not show a thermostat. The parts list that goes with the Model 40el71G does not list a thermostat. Does it have a thermostat? If so where is it located. I have an original 1971 Johnson 40 hp manual but have yet to find it listed.

 

[F_R]

Re: Does 1971 Johnson 40 have a thermostat?

The 40's were changed in 1971, no more thermostat. Actually it is "unchanged" to the point of being more or less a resurrected 1963 Gale 40. Was also sold with smaller displacement as a 28 and 33hp Evinrude and Johnson. If you want go back ever further, it is related to the 1955 models.

 

[kfa4303]

Re: Does 1971 Johnson 40 have a thermostat?

Yeah, my '66 33 hp didn't have a t-stat either. It was a great motor. It didn't seem to impair the performance in any way. One less piece to replace too.

 

[1946Zephyr]

Re: Does 1971 Johnson 40 have a thermostat?

Yea, I think those are actually the best 40's made. Much lighter than the previous models and easier to work on. F_R, are you sayin that this model 40 is the 40.5 cube vs. the 43.9?

If I'm not mistaken, the 50hp introduced in this year was a new design of the 43.9 with dual carbs and electronic ignition.

 

[1946Zephyr]

Re: Does 1971 Johnson 40 have a thermostat?

Yeah, my '66 33 hp didn't have a t-stat either. It was a great motor. It didn't seem to impair the performance in any way. One less piece to replace too.

Your 33 was infact a resurected '57 35 with a fiberglass hood. Most all parts are interchangable.

 

[F_R]

Re: Does 1971 Johnson 40 have a thermostat?

Yea, I think those are actually the best 40's made. Much lighter than the previous models and easier to work on. F_R, are you sayin that this model 40 is the 40.5 cube vs. the 43.9?

If I'm not mistaken, the 50hp introduced in this year was a new design of the 43.9 with dual carbs and electronic ignition.

No, the 33hp was 40.5 cu in. The 1960 thru 1970 40hp was 43.9 cubics. The 1971 40hp was also 43.9 cubes, but the block was the previous one used on the 33 but with bigger bore. The 50hp was a totally different motor with 41.5 cubes. As I said, the 1971 40 was actually the 1963 Gale 40 with a different hood. Are we confused yet?
Evinrude and Johnson motors were:
1955 25hp = 35.7 cubic inches
1956 30hp = 35.7 cubic inches
1957-59 35hp = 40.5 cubic inches in two different forms
1960's 33hp = 40.5 cubic inches (old form)
1960-70 40hp = 43.9 cubic inches (new form)
1971 40hp = 43.9 cubic inches (old form)
1971 50hp = 41.5 cubic inches. (Totally different)

 

[1946Zephyr]

Re: Does 1971 Johnson 40 have a thermostat?

Okay, I gotcha. So the 71 and new 40 is like the old 33, just punched out to the 43.9 cubes. Wow, that would be wicked, to put that powerhead on the 1957 35 Would just have to bolt on some wings to mount the rear part of the clamshell shroud with.

Wow, so the 50 was even smaller cubes than the 40's. Well, the dual carb set up would definately explain the boost in horsepower. So imagine this: A 1957 Lark style motor, with the 1971 40hp powerhead. To bad there isn't a dual carb set up for one of those. You'll probably be pushin' 60hp with the 44 cubes. LOL

 

[F_R]

Re: Does 1971 Johnson 40 have a thermostat?

Actually, there once was an aftermarket "dual carb" kit for the old '57's. i believe it was called a Jet Pac. It was a crude "carb" that went on the intake bypass cover. I installed one, and couldn't tell any real hp increase. But it ran worse. Needless to say I took it back off.

The 50hp came from more than just the second carburetor. Biggest factor was it was loop charged. Not only that, the flow path through the crankcase was worlds better than the old crossflows. And it had tuned exhaust. Last but not least, the thru-prop-hub-exhaust gearcase made a dramatic improvement in getting the horsepower to the water.

 

[kaneerarchery]

Re: Does 1971 Johnson 40 have a thermostat?

Thanks for all of the information. The motor runs great and pumps water well with the new water pump impeller. I just wanted to change the thermostat if it had one. Thanks.

 

[1946Zephyr]

Re: Does 1971 Johnson 40 have a thermostat?

Actually, there once was an aftermarket "dual carb" kit for the old '57's. i believe it was called a Jet Pac. It was a crude "carb" that went on the intake bypass cover. I installed one, and couldn't tell any real hp increase. But it ran worse. Needless to say I took it back off.

The 50hp came from more than just the second carburetor. Biggest factor was it was loop charged. Not only that, the flow path through the crankcase was worlds better than the old crossflows. And it had tuned exhaust. Last but not least, the thru-prop-hub-exhaust gearcase made a dramatic improvement in getting the horsepower to the water.

Yea, 1968 to 71 had a lot of revolutionary changes for the outboards, in the bigger class which a lot of these improvements are still in use today. The 50 and bigger motors were stage setters for outboard design.

Congrats on getting the issue solved kaneerarchery. That motor will do well for you now