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Old 03-04-2008, 04:47 PM
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Default RE: Quadra 52 won't run under 3500 HELP

Eugene,, any idea who might be a supplier?

Today I spent more time on the Q 52 w/Zama carb.

I added a slideplate choke. Wow what a difference this made in starting. I also adjusted the float valve pivot arm to allow more fuel. The engine is turning 7300 rpm with a 20 6x10 wood prop. So it is strong turning up.

I still can't get idle below 3100 but what I noticed was that with the choke partially closed I could idle lower. With the choke 2/3 open I could get 2700 rpm with leaning the LS needle. So I made an Adaptor plate. The carb dia is 11/16" but the choke slide plate is 1/2" so this is effectively a restrictor plate. By closing the choke increases the velocity of air through the carb. So,,, with this observation I made a restrictor plate with 3/8" hole. Basically sheet metal with hole at inlet side of carb. But before I could try it,, my tank ran out of fuel and have to go buy more. My starting 24 v battery also ran down,, so more tomorrow.

One thing I also noticed is by reducing the opening from 11/16 to 1/2" I had a lower idle but only lost 200 rpm on top end. So higher air velocity might help.

I will shop around for a W Carb. to see what's out there. Thanks Jim