compression for 1959 Johnson?

[roger56]

I will be trying to check the compession on 59 johnson 18hp Tomm. Where can i get a tester and what does it look like? What should the numbers be on the compression Test.

 

[HighTrim]

Re: compression for 1959 Johnson?

You could probably borrow one from you local Auto Parts Store, or get a cheap one from Harbor Freight.

http://www.harborfreight.com/flex-drive-compression-tester-92697.html

You will be in the 95 to 140 psi range. Important is the difference between cylinders. Should not be more than 10%, let us know what you find.

 

[roger56]

Re: compression for 1959 Johnson?

thanks i will check it out

 

[roger56]

Re: compression for 1959 Johnson?

Got a compression checker from son in law Good to go.

 

[boobie]

Re: compression for 1959 Johnson?

Have both spark plugs out when you check it.

 

[HighTrim]

Re: compression for 1959 Johnson?

Have both spark plugs out when you check it.

Yeah, and ground the leads. Small possibility of damaging the coils. Only takes a sec to run jumper leads to a bolt head.

 

[JB]

Re: compression for 1959 Johnson?

Look in the Top Secret File ^^ for procedure.

 

[roger56]

Re: compression for 1959 Johnson?

Checked compression today on 59 Johnson 90 PSI on both cylinders

 

[boobie]

Re: compression for 1959 Johnson?

Did you try to fire it up yet ??

 

[tx1961whaler]

Re: compression for 1959 Johnson?

90 is good. Actually pretty darn good for a pull start motor.

 

[roger56]

Re: compression for 1959 Johnson?

fired it up motor runs fine on low idle but no high speed. I have another post with history on my progress with this motor