1991 Evinrude 40hp, worth saving?

[GreenF350]

Hi everyone,
First post on these forums, looks like a great site. Anyway.... I just recently purchased a boat with a 40hp Evindrude on it and the motor is pretty rough...Low compression in bottom cylinder (60-70psi), lower unit leaks (didn't see any metal though) Boat seems to be very well taken care of, so I am betting mostly age has gotten to this motor. That being said....I have a line on a "cheap" rebuilt powerhead and I am more than capable of changing that out and resealing the lower unit. (I am a certified auto and aircraft mechanic, I just don't know very much about outboards.) Is there anything in the "center section" of the outboard that can go bad or may need to be looked at? The motor runs now, just not right of course, and the guy I bought it from was told it wasn't worth fixing, but the way I am doing the math, $1000 to fix it, $2500+ for a used motor, I would rather fix it. Thanks for any opinions, or ideas. Just don't want to get $$ into this one and then find out it is junk.
-Aaron

 

[JB]

Re: 1991 Evinrude 40hp, worth saving?

Ahoy, Green.

Welcome to iboats.

I think the first thing I would do is a thorough decarbonizing, then check the compression again.

If that didn't change things I would pull the head, inspect the gasket and look for cylinder damage.

Dealers who want to sell engines will very often tell customers their engines aren't worth fixing. All that really means is they want to sell you another one.

Let us know what you find.

 

[pduquette]

Re: 1991 Evinrude 40hp, worth saving?

Welcome aboard!
Your first investment will be the most valuable....spend $30-$60 on a good repair manual or best yet a gen-u-ine shop manual . If your skiled at cars and planes , outboards should be an easy study.
You should probably start by pulling the cylinder heads and ascess the bore . Scored? Burned/broken rings?...You get the idea.

 

[flabum]

Re: 1991 Evinrude 40hp, worth saving?

If you do the work, yes it is worth fixing. For a re-build: 2 pistons and rings $150, Gaskets $100, Machine shop Hone $40 or Bore $100 (maximum), bearings $200 Carb kits $40 and shop manual $30 -$60 ....Misc stuff $40

So, you see for about $700 worst case you can rebuild it yourself.

Then $40 for the lower unit seal kit and anothe $40 for a water pump.....where can you find a rebuilt motor for $800?

 

[samo_ott]

Re: 1991 Evinrude 40hp, worth saving?

What's the compression on the upper cylinder?

 

[GreenF350]

Re: 1991 Evinrude 40hp, worth saving?

The compression in the upper cylinder was about 115. I figured I could rebuild this thing myself and save some money. Flabum, that was about what I was figuring so that sounds pretty good. I did get an online subscription to Seloc, but I may try to find an actual manual. I will let you guys know how it goes. Thanks for the help/insight!
-Aaron

 

[tashasdaddy]

Re: 1991 Evinrude 40hp, worth saving?

if you are going to rebuild, you need the reprint of the OEM manual

"http://www.outboardbooks.com/index.cfm?fuseaction=models.main&year=1991&ID=81780"

 

[samo_ott]

Re: 1991 Evinrude 40hp, worth saving?

That's a big difference from 60-70 to 115. Definite work required... Hopefully as easy as a head gasket (it does happen).

You have an online subscription to Seloc? You can buy the Seloc manual for $30 so I hope the subscription does not cost you that much. But, as TD said, if you only have 1 outboard and are rebuilding it, get the OEM manual.