35 HP Compression Question

[vincelong]

What should the compression be in a 1984 Evinrude 35 HP short shaft
(E35RCRR)?

 

[samo_ott]

Re: 35 HP Compression Question

Compression numbers are not usually posted but somewhere in the 120 PSI range would be good and less than 5-8% different from each other.

 

[vincelong]

Re: 35 HP Compression Question

both cylinders are square on 90 psi after 5 pulls. Is this bad? Im guessing its time for a rebuild

 

[samo_ott]

Re: 35 HP Compression Question

90#'s via a pull start is not terrible. It'll run ok, it just wont go as fast as it could. There's no electric starter to test it with? As you will get higher numbers with a starter.

And did you test it with both plugs out and the wires grounded?

 

[JB]

Re: 35 HP Compression Question

I don't agree.

90 and 90 is great from a rope start outboard. Forget outboard hypochondria.

Run her and enjoy.

 

[vincelong]

Re: 35 HP Compression Question

why do you have to have both plugs out? I thought you kept the opposite in while you were testing the other. What would the difference be the cylinders should be sealed by the rings right?

 

[samo_ott]

Re: 35 HP Compression Question

Having both plugs out is the standard. Your #'s will also be a bit higher with both out due to less compression.

 

[Al-53]

Re: 35 HP Compression Question

the motor will spin a bit better with plugs out..no resistance....also if you want...spray some sea foam and let sit over night..may free up some carbon build up ...you may get a better reading..but as said..rope pulling does not give you a peak reading as if you used a power start...

As Jb said you should be fine....

Al

 

[vincelong]

Re: 35 HP Compression Question

thanks for your help guys