'61 Evinrude 40HP - Was Fast, Now Slow

[shawnswan]

I bought a '61 Evinrude Lark 3 40HP a couple of weeks ago. It hadn't been run since last year. I put it in the lake and it ran perfect. I've had it out 3 or 4 times since and it was pretty fast. I accidently forgot to check the gas gauge last week and ran it out of gas. Since then the boat only goes about half the speed that it did before at full throttle. I can reverse and rev the engine pretty high in neutral. I did manage to get it up to full speed again at one point but after stopping it for a couple of minutes, couldn't get it back up to full again.

I'm thinking it's the carb, and I've got a kit on order. Just wanted to check to see if anybody else had any ideas while I've got the motor apart.

Thanks.
Shawn

 

[Chris1956]

Re: '61 Evinrude 40HP - Was Fast, Now Slow

Make sure both cylinders have spark. You might check that the spark is a blue snappy type spark.

 

[F_R]

Re: '61 Evinrude 40HP - Was Fast, Now Slow

I bought a '61 Evinrude Lark 3 40HP a couple of weeks ago. It hadn't been run since last year. I put it in the lake and it ran perfect. I've had it out 3 or 4 times since and it was pretty fast. I accidently forgot to check the gas gauge last week and ran it out of gas. Since then the boat only goes about half the speed that it did before at full throttle. I can reverse and rev the engine pretty high in neutral. I did manage to get it up to full speed again at one point but after stopping it for a couple of minutes, couldn't get it back up to full again.

I'm thinking it's the carb, and I've got a kit on order. Just wanted to check to see if anybody else had any ideas while I've got the motor apart.

Thanks.
Shawn

It isn't the carburetor, best to leave that alone and not create a second problem. Your motor is running on one cylinder. Your task is to troubleshoot it and find out why. The carburetor feeds both cylinders, and it can't just feed one. First thing to check is the spark plugs. While you have them out, also check the compression, just to make sure it isn't something worse. And check for signs of water in the cylinders/plugs.

If all that checks out ok, it is time to get serious and pull the flywheel and see what's wrong in there. Could be anything from dirty breaker points to a bad coil. Given the age of the motor, the coil is a very real possibility.

 

[shawnswan]

Re: '61 Evinrude 40HP - Was Fast, Now Slow

Plugs......I can't believe I didn't think to check them!!!

Hopefully that's the problem.

Unfortunately I have nothing to test compression.

Are cracked coils hard to replace?

Thanks.

 

[shawnswan]

Re: '61 Evinrude 40HP - Was Fast, Now Slow

So I checked the plugs this weekend. The top plug was cover in gas and oil, the bottom plug was clean. I cleaned them both. Tried starting with just the top plug and it wouldn't turn over. Did the same with just the bottom plug and it turned over no problem. Coil it is!
I'm going to try to find one this week. Will this be hard to find? More importantly, will it be hard to replace?