1965 40HP Evinrude Big Twin lower unit

[cz1234]

I have a perfect running power head for this motor (which I have tweaked to perfection) and an unidentified lower unit for it... It is clearly not the original. I wore out the clutch dog but cannot get a replacement since I cannot determine the year or size of the attached lower unit. I am looking for either: 1. How do I figure out what size and year the lower unit is so I can just get the part I need? 2. Get a compatible lower unit for the motor, 3. OR the same lower unit.<br /><br />I am a wizz at removing the lower unit since I've done it many times!!!! I tried to dremel the clutch dog and forward gear so that they would not slip when engaged which worked for a while but it is starting the slip again.....<br /><br />cz@lakecom.com for direct contact.....

 

[Paul Moir]

Re: 1965 40HP Evinrude Big Twin lower unit

Welcome to Iboats, CZ!<br /><br />I think that the dog didn't get changed for many years (I don't think any changes between the late 50s and the early 70s), so it probably isn't important to pin it down exactly. That said, I think somewhere around '64 they changed the pinon bearing from a tapered roller bearing to a seperate thrust and drawn cup needle bearing. About the same time, they changed the propshaft to the one with a drilled hole and detent balls for the dog. The dog was grooved so it would click into neutral, but it still worked fine on undrilled propshafts. <br />In '67 they went to the water pump that has the pickup tube coming right up from the inlet screen rather than coming up from the pump base. That can easily be identified by the three tubes hooked up to the pump rather than the usual two. That system got dropped in '71 when they went back to a single water tube on the 40hp. <br />Other than that, I don't know any changes in it up to the '70s. Sometime around then though they changed the cap to have a skedge with a sort of straight leading edge on it though, rather than the curved one.<br /><br />Hope this helps some!

 

[cz1234]

Re: 1965 40HP Evinrude Big Twin lower unit

I found someone with a 1965 Johnson 40HP seahorse. Is that the same motor as the 1965 Evinrude 40HP big twin? Are the lower units compatible?

 

[Paul Moir]

Re: 1965 40HP Evinrude Big Twin lower unit

Yes, those engines are identical except for the cowl and paint.<br /><br />Good luck!