Sleeve Discoloration?

Brandon Atwell · Dec 30, 2019

Hey everyone!
Just pulled this sleeve out of my Nova 35Plus outboard engine.
Backstory, this was a factory tuned and broken-in sleeve from Nova.
I may just not know what those broken in sleeve typically look like, but is the discoloration pattern on this sleeve typical? The sleeve from my 35Plus in my .21 hydro does not have a color pattern like this but it was not factory broken in. Any ideas or just from their process?

Tore the motor down as last time I tried to run it, anything past idle and the engine would die. Figured an air leak or something simple but wanted to double check.

JAMEYGALLIHER · Dec 30, 2019

all that discoloration is fuel getting between the sleeve and block and heat cycles

Terry Keeley · Dec 31, 2019

I get a little of that around the exhaust port but it cleans right off with solvent.

Think you'll only see it if the motor is run at the right temps...

BobBonahoom · Dec 31, 2019

Perhaps has something to do with Nova's "castor oil break in"? Rod Geraghty told me that they intentionally use a lot of castor and run the break-in very hot so it is probably the castor combustion varnish. A good thing perhaps...maybe it helps seal the engine?

Kez · Dec 31, 2019

All my engines have the same discoloration. The top portion of the sleeve has good fit to the case and is protected from the fuel and therefore is still shiny

brad nichols · Dec 31, 2019

Will Make the sleeve hard to pull out after time.

Brad

David Ashcroft · Dec 31, 2019

Do not polish the sleeve..!
Particularly below the ports.

Buckshot · Jan 9, 2020

David Ashcroft said:
Do not polish the sleeve..!
Particularly below the ports.

Care to share why?

David Ashcroft · Jan 9, 2020

Buckshot said:
Care to share why?

Atomization.

Sleeve Discoloration?

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