Evinrude 1975 115HP - worth re-building?

[rude70]

I have just bought a cheap 1975 115HP Evinrude. I was told that one cylinder is down on compression 90psi the others are 110. I have to check these, but is this a good model to rebuild? I recently re-built a 1977 70HP so it looks pretty similar. Also it doesn't have tilt & trim, since it use the old hard to get twin ram exteernal unit, can the power head and gear box be put on a latter mid-section with internal t&t/

Thanks in advance

 

[oldcatamount]

Re: Evinrude 1975 115HP - worth re-building?

Those compression numbers aren't really that bad. Ideally, the numbers should be within 10% of each other and yours are close. I would try a de-carb treatment and see if the lower piston will increase it's compression a little bit before taking the motor apart. If that doesn't help, I believe the motor is worth a re-build as long as you are doing the majority of the work yourself. You may be able to just have the cylinders honed instead of a complete re-bore job. As far as switching to another mid-section goes, I'm not going to be able to help you with that but, someone else on this forum probably can.

 

[rude70]

Re: Evinrude 1975 115HP - worth re-building?

thanks, I thought it would be a solid mtoro since the '77 70HP is excellent.
I will follow your suggestions

 

[ezmobee]

Re: Evinrude 1975 115HP - worth re-building?

Great motor especially since good used motors are a little tougher to find in your part of the world also correct? I had a '73 that I ran for five seasons before selling it in excellent running condition. I now run an '81 which I actually consider kinda new

 

[emoney]

Re: Evinrude 1975 115HP - worth re-building?

Sounds like a great platform for a rebuild and an awesome choice to do a thread on. Great idea, so keep those pics a'coming! (hehehe)

In all seriousness, that would be a cool thread to follow; a complete rebuild. Just to weigh in, I've always had a lot of faith in these old Evinrudes. I'm about as far away from being a mechanic as a guy can get, and even I feel comfortable getting into them. Great tip about the 'de-carb', and at worst it might need a new head gasket since those numbers are pretty close. Keep us posted.

 

[rude70]

Re: Evinrude 1975 115HP - worth re-building?

Thanks guys I will keep you posted, it is great to learn from others experiences. The motor did not come with tilt & trim, so I will take the unit from my 1977 70HP and found out that I can update the mide section on the 70HP to a slightly later model with easy to get internal t&t

 

[bfmiller]

Re: Evinrude 1975 115HP - worth re-building?

Thanks guys I will keep you posted, it is great to learn from others experiences. The motor did not come with tilt & trim, so I will take the unit from my 1977 70HP and found out that I can update the mide section on the 70HP to a slightly later model with easy to get internal t&t

Hey there,
How did your rebuild go? I recently also bought this type of engine and found out it needs a complete cylinder rebuild. Me and my mechanic friends were thinking about making this a project. Any tips or suggestions and was it worth your time?