1960 Evinrude 40hp Lark Help!

[elvis53]

I have a 1960 40hp Evinrude Lark. Yesterday I got it started with new plugs, took it out and it was only going half speed at full throttle. Then it took off at full speed.

Today it started right up and when I put it at full throttle again it would only go half speed, only this time it did not come out of it.

I have fresh fuel and plugs in it. Any suggestions what would cause the engine to go half speed under full load?

Thanks!

 

[tx1961whaler]

Re: 1960 Evinrude 40hp Lark Help!

It is probably only running on one cylinder. Try running a spark test. It's best to use a spark tester (8 bucks at the auto parts store), but you can try holding the plug against the cylinder head to see if it sparks.

 

[elvis53]

Re: 1960 Evinrude 40hp Lark Help!

Tx1961Whaler,

Thanks for the help I will try it first thing in the morning and let you know if that was the problem

 

[coolguy147]

Re: 1960 Evinrude 40hp Lark Help!

how long did it take for it to go to half to full speed?



i would add if it hasnt beeen services in a while u will need to change the impeller. and many other maintence items. very easy to work on by the way

 

[F_R]

Re: 1960 Evinrude 40hp Lark Help!

Any time a two cylinder/single carburetor motor runs at half speed @ full throttle, it is running on one cylinder. Almost always a spark problem. The not-so-nice possibility is no compression or water in the missing cylinder.

 

[coolguy147]

Re: 1960 Evinrude 40hp Lark Help!

gotta f r


ok well first off id check compression see if its good. most likely u dont have a water in cylinder problem but there always is a possbility. so we need a compression check first. then check spark see how good spark is

 

[elvis53]

Re: 1960 Evinrude 40hp Lark Help!

As far as how long it took to go from half speed to full throttle. I was taking it out for the first time and noticed it was only going half speed and headed back to the dock when it just took off at full throttle, so I would say less than five minutes.

Thanks

 

[coolguy147]

Re: 1960 Evinrude 40hp Lark Help!

u had the cover on while running it right? only other thing i could happening is that u ahve an exhuast leak and it was in the cowling and was choking the motor till it it had enough clean air in there to run right. but mostlikely u dont.


for now just check compression so we can see if the motor is worth acually working on and see about the water in cylinder theory

 

[tashasdaddy]

Re: 1960 Evinrude 40hp Lark Help!

read the TOP SECRET FILE.

 

[elvis53]

Re: 1960 Evinrude 40hp Lark Help!

tashasdaddy,

Thanks for the advice, but I am new to this forum. How do I get to the TOP SECRET FILE? Thanks

 

[tx1961whaler]

Re: 1960 Evinrude 40hp Lark Help!

The TOP SECRET file is the first post in the Johnson/Evinrude repair forum. It has links to common issues.