Is my 1965 Evinrude 9.5 DOA?

[Coho99]

My old Evinrude Sport Twin has been lacking power so I decarbed it several times. There was no improvement in performance. I checked compression and it has around 40psi on both cylinders. I'm considering tearing the power head apart to install some new rings. The big question is whether this will do the job or whether other problems are present that will require parts costing more than the engine is worth. What are the likely scenarios here? Any advice will be appreciated before I spend the time working on the engine.

Steve

 

[Daviet]

Re: Is my 1965 Evinrude 9.5 DOA?

I think I would pull the head and check the pistons and cylinder walls, if all was ok, install a new head gasket and recheck compression.

 

[bktheking]

Re: Is my 1965 Evinrude 9.5 DOA?

I'd start by pulling the head, you may have a bad headgasket. It's not just rings, it's a gasket set, the omc sealant, the gel to put the 2 halves back together, it's the hone you need to use to remove the glaze on the cylinders, the measurement tools to check tolerances, block may need to be bored in which case you are getting into oversized pistons and rings. Don't get me wrong it can be done but without checking everything out you might be throwing your money away, 9.5's are a dime a dozen, you may be better off buying a 9.9, better motors, better power. I have a 1965 same as yours, I bought it for 2 bills.

 

[jeff_smith_0423]

Re: Is my 1965 Evinrude 9.5 DOA?

The aluminum used to build those cowlings was very prone to corrosion, too. The rubber motor mounts degrade and may fall apart if you get to the point of reattaching the powerhead.

I would probably do a headgasket as a hail mary and if that doesn't work, move on. Plenty of them around for cheap. A few more bucks can get you a much better designed 9.9.

I've got one sitting in the garage that has great compression and ran beautifully till the part on the port side cowling that the throttle mechanism bolts into decided to snap in half. I can't give it away. If I can find a donor motor, i might tear it apart over the winter and try to fix it

 

[bktheking]

Re: Is my 1965 Evinrude 9.5 DOA?

I almost had 2 here locally 2 weeks ago, 1 for parts and 1 ran, the guy wanted $50 for both but sold them from under me. I wasn't impressed.

 

[samo_ott]

Re: Is my 1965 Evinrude 9.5 DOA?

2 x 9.5's were in Carleton Place? Dang, I'm gonna be there tomorrow! I'll have to watch closer...

 

[crxess]

Re: Is my 1965 Evinrude 9.5 DOA?

Did you confirm with a second compression tester? These tools are not numerically reliable.
Did you have goth plugs out and pull rope several times?
Typical reading on this motor is 70/70.

40/40 would indicate severe wear. Possibly head gasket but unlikely. Water jackets surround each cylinder so a compression swap without water ingestion is unlikely.
Can't hurt to pull the head and have a look.
Pull the head off.
Inspect cylinder walls.
Center pistons in bores(top to bottom)
Wiggle test pistons.
Pistons should have little to almost no side movement.
Loose is bad.

 

[bktheking]

Re: Is my 1965 Evinrude 9.5 DOA?

2 x 9.5's were in Carleton Place? Dang, I'm gonna be there tomorrow! I'll have to watch closer...

As the story goes, 2 weeks ago they went up on usedottawa, 2 for $50. I immediately called the guy, he had them in constance bay. I said I want them I'll be by tomorrow morning to get them, promise me you'll keep them. Guy tells me he wont' be home till the night, wouldn't work for me. I tell him I'll call you Sunday, Monday morning the latest to come get them. Call him Monday morning he says I sold them. I said WTF you told me you'd promise to hold them, he says I didn't here from you Sunday so I sold them. I was livid!!!!

 

[Coho99]

Re: Is my 1965 Evinrude 9.5 DOA?

When I ran the compression test, I had the other plug in the cylinder. I'm not sure what this does to the accuracy of the test but the low compression results make sense when compared to the low power output of the motor (about 4hp is my guess).

As far as a bad head gasket goes, will there be any obvious signs of this problem present when the engine is running? I've pulled the cover off the engine several times when it has been running and I didn't notice any exhaust, if this is an indication.

It seems as though repacement of the head gasket would make sense if there is a remote chance it will work. Am I correct in assuming this would cost around $30? Pullling the entire head apart to install new rings with all the parts and tools is looking like a $200+ job if all goes well. If this is true, going this far is too much compared to the remaining value of the motor.

 

[Rick.]

Re: Is my 1965 Evinrude 9.5 DOA?

Well your right about the value of the motor hot being worth the rebuild but like so many have said do the head gasket as a hope and a prayer. You might be surprised. The numbers are identical and that is a good thing. There could be a head gasket leak between the two cylinders. the other thing that has been mentioned is the accuracy of the gauge itself. It would not hurt to have another on hand after you do the gasket. It's a long shot but one worth taking IMO. You can't normally get two of these things for $50.00. Rick.

 

[Coho99]

Re: Is my 1965 Evinrude 9.5 DOA?

Thanks for the advice everyone. I'll be trying a new head gasket and hopefully another compression gauge. If this doesn't work, it's time to shop for another motor.

 

[jay mendoza]

Re: Is my 1965 Evinrude 9.5 DOA?

The exhaust could be blocked with carbon, which would result in poor power. This also restricts the heat flowing out and over heats the pistons, baking the carbon into the ring grooves; then the rings stick in the grooves and won't seal. With the head off you can put the pistons to the bottom to uncover the exhaust ports and look for heavy carbon build-up that would cause a restriction. Moderate carbon is acceptable. If the cylinder walls have minimal wear and scoring, you can try running the engine until it is hot and then spray de-carb sauce directly into the spark plug hole with the piston at the top(TDC), and let it soak with the cylinders vertical, for 15 minutes and repeat for the other cylinder( put it at TDC). This method gives the pure de-carb sauce a chance to seep past the rings and grooves, thereby loosening the carbon and freeing them up.