otisflies

For some reason my new ZDZ80 twin won't stay running unless I hold the choke half way on it. If the choke is all the way open it runs for about half a second and then quits. If I hold the choke at about half way it will stay running. I am not experienced with gas engines so any help is appreciated. Is this a carb problem or fuel draw or what?

Thanks

rmh

you just are not getting fuel delivery - why -I don't know
the usual reasons are restricted fuel flow OR leaking gasket on carb base - tho you may have another problem

otisflies

Seems I had the butterfly backwards. Flipped it around and now it runs fine. I didn't think that would produce the problems I had but it works fine now.

rmh

that completely screws up the air flow over the discharge holes in the carb - -they rely on low pressure across them to operate

Mike Dooley/RCS

Thanks for responding Dick. Yes, The reversed throttle butterfly is a huge problem when guys modify the carbs and are not aware of the physics of the operation of a carburetor. Yes, we are including updated info to our manuals about this, but half of the people don't read them anyway!!
Mike Dooley
RC Showcase

otisflies

Well if it makes you feel any better Mike....I read it in your FAQ and it saved me some time and aggravation so its worth putting them up.

Terry