Purple Pilot

Hi guys,
I'd be very grateful if someone could tell me what the rectangular (obround?) cut-out in the side of my Wacker Engines Ryobi mount is for? Basically, I'm just about to attach the mount to my firewall and I need to know which way up it should go The Ryobi will be mounted inverted - exhaust pinting downwards - by the way.

Many thanks!
Steve

ALW Phantom

My Feedback: (2)

I could be wrong but Im sure if you check with Peter at Wacker he will tell you its for throttle linkage acess. Everytime I have called him he has had the time to talk with me and is a very nice person as well.

mikenlapaz

This should give you an idea. Found a used rowing machine frame that wanted to go flying!

Purple Pilot

Hi guys,
Thanks for the replies... and yup, you're right, it's for the throttle access &/or movement. What threw me is that on the 'big bore' 473(?) carb I got from Peter it has a real long choke arm that points in the complete opposite direction to the throttle so the hole in the mount could've been for that if you turn it thro 180 Peter says to junk the choke anyway another 1/4oz lighter![sm=thumbup.gif]
Steve

mikenlapaz

you might want to check the throttle linkage clearance to the front inside wall of the mount. I needed an indentation for linkage to go to full. You could always drill a hole on the other side for the choke arm access. Seem I read somewhere that some Walbro chokes have an extra fuel channel that opens when carb is closed and a detent for a ball. Check the model diagram at : http://wem.walbro.com/walbro/family2.asp

Volfy

My Feedback: (23)

Don't go junking the choke just yet. It is very useful for choking and can even be used as an engine kill. A good friend of mine had a stuck throttle on his Patty Wagstaff and ended up tearing up the plane trying to land it with power on. Had he had a servo actuated choke, he could've killed the engine in flight.

Especially for the rear carb Ryobi, manual access to the carb throat for priming can be difficult. I doubt even TOC-class pilots can notice 1/4Oz difference.

mikenlapaz

a stuck throttle is problem as Volfy described. Additionally, for the possibility of a throttle linkage coming loose, I retain the return spring, just take some of the tension off by letting loose end unwind abit to contact a different position on the carb body or remove throttle shaft and let it unwind 1 revolution and replace shaft.

Purple Pilot

Thanks for the good advice gentlemen [sm=thumbup.gif]

Do you also advise soldering up the little 'nick' / groove in the brass carb butterfly so as to be able to totally shut off the throttle?

mikenlapaz

Whether a nick, groove or hole, SI. Your throttle servo is going to control full closure.
Copy down that carb series/model number (two lines top corner , opposite side from the needles) (WT WA etc series) and below that the carb model. (beats big bore 473? for ID ) when you need a replacement part, etc.

Purple Pilot

Thanks Mike, will do [sm=thumbup.gif]