what would be similar to a 40 HP

[joe_morgan]

Hi All, I have been canvasing these forums for months now and its occurred to me that I might be able to get more from these some of articles if I knew what other motors were similar in design to mine. I have a 1975 40hp evinrude. So I image a motor from late 60's from 25hp through to 50hp may be similar.<br /><br />Cheers<br />Joe

 

[joe_morgan]

Re: what would be similar to a 40 HP

hey I just realised, I'm a seaman apprentice.<br />I must have missed the ceremony.<br />Joe

 

[Mark42]

Re: what would be similar to a 40 HP

That same twin cylinder was carried all the way through into the 90's. I think Johnson still had the same 45 cid twin in 2002.<br /><br />They are basically the same with minor differences in reed plate design, carbs, exhaust ports and piston tops. <br /><br />Lots of parts are interchangeable, some are not. Doesn't hurt to read about them.<br /><br />Congrats on the promotion.

 

[fireman57]

Re: what would be similar to a 40 HP

We were all there but wondered where you were. If it matters we all had a good time.

 

[WillyBWright]

Re: what would be similar to a 40 HP

Too bad you missed the party, Joe. Strippers, gambling, beer til I puked. God, it was Beatuiful!

 

[McGR]

Re: what would be similar to a 40 HP

Joe:<br /><br />Your motor is basically derived from the OMC " Big Twin" two cylinder design. These motors originated in the early 50s as a 25hp. In '56 they were bumped to 30hp. In '57 the were bumped up again to 35hp. Somewhere around 1960 it was increased to 40HP. Throughout the 60's Johnson and Evinrude offered this style of motor in a variety of horsepowers: 28,33 & 40 (maybe even a 35?). In the 70's I beleive this motor was primarily sold in a 40hp version (like yours). From what I understand they continued making this motor for commercial applications into the 80's. I don't believe the output of this family of motors ever exceeded 40hp. So, information on 50hp motors would not be applicable to you. Additionally, late 65's 25hp were based on a smaller engine design than yours, so information on these would have limited applicability. All of the "Big Twin" family motors have distinct similarites but they also have differences. So, if you are looking for specific parts you need to consult parts manuals first.

 

[phatmanmike]

Re: what would be similar to a 40 HP

EDIT: <br />SCOTT IS THE SMARTEST GUY IN THE WORLD!!!!<br /><br /><br />i, on the other hand... am not

 

[Chinewalker]

Re: what would be similar to a 40 HP

Mike... The Big Twin design, which consisted of a cross flow style powerhead, was last used on the 40hp Commercial motor in the early 1980s. About the only part it shares with the big 2-cylinder looper design (which was built as 40, 45, 50, 55, and 60hp incarnations) is the lower unit drain plugs...<br />- Scott

 

[Paul Moir]

Re: what would be similar to a 40 HP

It's a small detail, but the 70's 40hp engines more closely resemble the '60s 28 and 33hp outboards than the '60s 40hp. Specifically, it uses a near-identical exhaust housing, and steering swivel bracket as opposed to the '60s 40hp 'Super Quiet' configuration. Since the 70s 40hp engines have no thermostat, they use a single-line cooling system which has a head and base gasket more like the smaller and older engines.

 

[Mark42]

Re: what would be similar to a 40 HP

Boy, I guess I stand corrected. So 70's and 80's 40hp has nothing in common with the 90's 40, 45, 48, 50 & 55?<br /><br />Paul, my 93 40hp does have a thermostat.

 

[McGR]

Re: what would be similar to a 40 HP

The 80s 40hp have a lot in common with the 90s motors you mentioned. As you mentioned, these type motors were made up until a couple of years ago. However, in the 70's this style motor was generally rated between 50 to 60hp. I think all of the 2 cylinder looper motors had thermostats. The motor Joe has is the earlier crossflow type.

 

[McGR]

Re: what would be similar to a 40 HP

I just stopped by the Johnson site for the heck of it. It looks like they are still making the 45CID loopers in 40 and 50hp flavors. I thought for sure they would have pulled the plug on these by now. They sure are getting their money's worth out of that design. Those style motors were introduced over 35 years ago. Dang!

 

[Mark42]

Re: what would be similar to a 40 HP

The reason I decided on a Johnson/Evinrude motor for my boat was that the 40 hp had been made for so long in its current configuration that I figured they HAD to have all the bugs out by now. My research indicated that there was no common failure or problematic weak spot in their twin designs. Reliability and economical maintenance were at the top of my requirements list. This motor fit the bill.