by Shorty Wright » Mon Apr 04, 2011 7:31 am
I just came across this and see that no one has posted a reply... your engine is/was and excellent sport engine. I have several 6535s and 6525s. and used to fly the crap out of them in the mid/late '70s
The pump engine had a larger Perry carb and, with the exception of the pump/carb, is identical to the 6525 which has a smaller Perry carb and no pump. The ring part number is 4005, by the way.
If you can fix the engine and intended to use it, you'll find it's more reliable if you swap the pump and carb for standard 6525 parts. Since the pump carb is a larger diameter base, you'll also need a sleeve. If I remember right, this was also available from K&B, so some should be out there somewhere. I also seem to remember making sleeves from sheet brass....
Part numbers:
Back plate7772
carb8040
piston ring4005