Evinrude Lark IV Compression

[sawmkw]

I have a 1962 Evinrude Lark IV, 40 hp outboard motor that my father bought new. It was last started 4 years ago and was winterized at that time but since has been sitting in the garage at the summer cabin. Over the years it has lost some of it's pep but was professionally maintained throughout it's life. I will be traveling there in a couple of weeks and wanted to do a compression check to see what the health is; maybe bringing it back for a freshing up or rebuild. My problem is that I do not know what the original compression was for comparison. Any ideas? Anything else that I could check at the time? Thanks very much!

 

[Chris1956]

Re: Evinrude Lark IV Compression

There are no recommended compression specifications on 2 cycle outboards. You want both cylinders to be even in compression and more than 90PSI. Now that presupposes that your compression gauge is accurate.

In short, if they are both close in compression (within 10%), and at least 90PSI, the motor is tunable.

 

[evinrude70hp]

Re: Evinrude Lark IV Compression

90psi+ and make sure all the cylinders are within 10% of each other.

 

[sawmkw]

Re: Evinrude Lark IV Compression

Thanks for the replies. Now one other question. Would that 90 lbs be on a hot engine or cold?

 

[evinrude70hp]

Re: Evinrude Lark IV Compression

cold. i belive.

 

[tashasdaddy]

Re: Evinrude Lark IV Compression

to make it, reliable expect to replace points, condenser, coils, plug wire, impeller, and carb kit. laingsoutboards.com carries it all.

 

[sawmkw]

Re: Evinrude Lark IV Compression

Thanks very much! I had not gotten to questioning where to get parts and very much appreciate the info. Would that be the best place to get a shop manual as well or is it really needed?