KR> Wide Open Throttle (WOT) Spring
Grumman Tr2s have a WOT spring on them and thank goodness they do. Years ago, shortly after coming out of an annual inspection that included a carb rebuild the throttle push/pull came unhooked due to the nut falling off of the swivel. The throttle went wide open and allowed me to go to my home airport. Once I knew the field was made, I pulled mixture and landed. If it didn't have a spring on it, I would have had to land somewhere in the weeds. I never took my airplane back to that mechanic. The Throttle on 2 strokes almost exclusively have the throttle slide to go closed if the throttle breaks. I don't like that, but that is the way it is by design. Maybe install a lighter spring as it shouldn't take much at all to bias to WOT. The one on the Marvel Schebler carb is a big round spring surrounding the throttle shaft and twists to open. Kevin Golden Harrisonville, MO In a message dated 6/18/2015 6:57:00 P.M. Central Daylight Time, krnet at list.krnet.org writes: I have a Zenith carburetor on my 2180 VW. I installed a WOT spring on the throttle plate shaft that would open the throttle in case the the throttle control linkage disconnected for whatever reason. The logic is to have the engine run full RPM rather than idle for a forced landing with no throttle control. Engine operation could be managed by switching the ignition on and off. Backfires something terrible when I do that. Question: How often do throttle linkages break? What prompts the question is: The WOT spring on my carb is holding the throttle plate a little open so that I cannot get down to 800 RPM idle. I disconnected the spring and everything works OK. Sid Wood Tri-gear KR-2 N6242 Mechanicsville, MD, USA ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org please see other KRnet info at http://www.krnet.org/info.html see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options
KR> Wide Open Throttle (WOT) Spring
I have a Zenith carburetor on my 2180 VW. I installed a WOT spring on the throttle plate shaft that would open the throttle in case the the throttle control linkage disconnected for whatever reason. The logic is to have the engine run full RPM rather than idle for a forced landing with no throttle control. Engine operation could be managed by switching the ignition on and off. Backfires something terrible when I do that. Question: How often do throttle linkages break? What prompts the question is: The WOT spring on my carb is holding the throttle plate a little open so that I cannot get down to 800 RPM idle. I disconnected the spring and everything works OK. Sid Wood Tri-gear KR-2 N6242 Mechanicsville, MD, USA
KR> Wide Open Throttle (WOT) Spring
My theory is that no certified plane I know of has a spring to open the throttle, so I don't need one on my experimental either. If I did put on a spring it would be a weak one and connect to the throttle linkage arm. I also believe in good aircraft type of throttle controls with no play in the system so the throttle stays where I put it. Original Message Subject: KR> Wide Open Throttle (WOT) Spring From: Sid Wood via KRnet List-Post: krnet@list.krnet.org Date: Thu, June 18, 2015 4:56 pm To: Cc: Sid Wood I have a Zenith carburetor on my 2180 VW. I installed a WOT spring on the throttle plate shaft that would open the throttle in case the the throttle control linkage disconnected for whatever reason. The logic is to have the engine run full RPM rather than idle for a forced landing with no throttle control. Engine operation could be managed by switching the ignition on and off. Backfires something terrible when I do that. Question: How often do throttle linkages break? What prompts the question is: The WOT spring on my carb is holding the throttle plate a little open so that I cannot get down to 800 RPM idle. I disconnected the spring and everything works OK. Sid Wood Tri-gear KR-2 N6242 Mechanicsville, MD, USA ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org please see other KRnet info at http://www.krnet.org/info.html see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options