Johnson Evinrude Displacement 35, 40 HP 1959, 60

[KirbyE]

What is the displacement of my 1960 40 HP Lark Evinrude Model 35520?<br />I have a 1959 Johnson 35 HP and it clearly says 40.5 CID. The 40 appears the same, but what can you tell from the outside. It has no indication of displacement. The real question is: what's the difference? Is this another case of different Carburators? or valving (porting)? or exhaust? for the same bore/stroke? I found info (within this forum) stating the 33 HP is also 40.5 CID. And, as if you couldn't guess, my 40 powerhed is fine but the rest is shot,(parts donor) so I might swap it into the Johnson for the addded HP. Somebody tell me if I'm wasting my time, and should just swap the carb or something.<br />The discussion earlier about HP v. Displacement was entertaining, but I don't feel the need to revisit that here! <br />Thanks a bunch for your time and interest.

 

[jimmbo]

Re: Johnson Evinrude Displacement 35, 40 HP 1959, 60

43.9 cu. in. I think the bore was increased.

 

[CATransplant]

Re: Johnson Evinrude Displacement 35, 40 HP 1959, 60

If the 40hp powerhead is good, I'd swap the whole thing onto your 59. It's a direct fit between the '59 and '60.<br /><br />Swapping the carb won't do a darned thing for you. I tried it, using a 40hp carb on my 35hp 1958 Johnson. <br /><br />The swap will give you a skosh more power, but nothing else, including the weight, will change.

 

[JB]

Re: Johnson Evinrude Displacement 35, 40 HP 1959, 60

The bore went from 3 1/16" (1959 35hp) to 3 3/16" (1960 40hp).<br /><br />That Increased the displacement from 40.5ci to 43.9ci.<br /><br />There may have been port size or timing changes, too, but I cannot ID them. Carbs were identical.<br /><br />Good luck.

 

[Paul Moir]

Re: Johnson Evinrude Displacement 35, 40 HP 1959, 60

One thing to watch out for with swapping big twin powerheads is there's two different types. Not a problem for you KirbyE, since both those fit in the same class. But out of interest, here you go:<br /><br />Thermostatically controlled engines with round bases and muffling midsection covers:<br />40.5 35hp 1958 (Lark and Super Seahorse only), 1959 (all 35hp engines)<br />43.9 40hp 1960-1970<br /><br />Thermostatless engines with squareish bases and exposed normal type midsections (that get really hot!):<br />35.7 25hp 1951-1955<br />35.7 30hp 1956<br />40.5 35hp 1957-1958 (Seahorse and Big Twin only in '58)<br />35.7 28hp 1962-1964<br />40.5 33hp 1965-1970 (71 outside US?)<br />43.9 40hp 1971-1975 (and onward in commercial service)<br /><br />I'm not sure about port timing changes between the 40.5 and the 43.9, but I strongly suspect there are to accomodate the extra CIs. There is between 35.7 and 40.5, but I've only measured two of those.

 

[KirbyE]

Re: Johnson Evinrude Displacement 35, 40 HP 1959, 60

Thanks to everyone. It seems 100% clear now. Paul, you have addressed another thing I have wondered about: Are the Lower Units the same for these two styles? (With/Without muffling midsections) I aquired a "spare" lower unit (I think off a 33 hp) assuming they were the same but I now see it is not. Very close, but only one coolant tube, smaller waterpump, VERY slight profile difference, and different bolt pattern. Is this another difference between "motormounts showing" and "motormounts covered"? <br />What I didn't share before is the 40 is ELECTRIC START ! so that seals the deal.<br />Thanks again.