Re: Posa carbs

Dorothea Keats and Chris Walterson <dkeats@...>

Richard----- Regarding your problem. I do not like using an
automotive compression tester. The readings aren't accurate enough.
You need to borrow a differential compression tester. This is what is
used on airplane engines. You put air into the cylinder and see how much
stays. I am sure you are gonna hear air leaking around your valves. If
you haven't got access to one, simply put 80 lbs of air into the
cylinder when the piston is at TDC on compression and you can listen in
the intake or exhaust for valve problems ot the crankcase for ring
When you do your runup and get to 2600, pull the nixture and if it speed
up, you're rich and if it slows down, you are lean.
As a last resort, borrow a smaller prop and tune your engine. You will
get your static rpm but when you bolt on your bigger prop, you will be
back to the 2600.
As I said before, I think your engine is week. You need to check the
compression as I suggest and then we can eliminate or confirm the health
of the engine. You need very good compression to achieve the 75 hp.
Have fun--------- Canada Chris

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