|06-17-2008, 02:22 PM||#1|
RCC Senior Contributor
I am: Chris K.
Join Date: Aug 2006
Location: Caledon, Ontario
Feedback: 21 / 100%
Total Props: 3
MVVS 26 Engine Cutting out Unexpectedly
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I have a just broken in MVVS 26 gas engine (this is my first gasser). I was at the field on the weekend trying to do a maiden flight but the engine kept on quiting on me for no apparent reason. The engine is installed in a 1/4 scale Piper Super Cub with the ignition module on the front of the firewall, the ignition battery is at the front of the cabin and the receiver and receiver battery are at the back of the cabin, there is a 42 Percent Products Opti Kill Switch installed. The following outlines what has happened to date;
1) Engine broken in as per manufacturer's instructions with no problem.
2) Engine starts quite well, normally after 3-4 flips (after priming)
3) When doing maiden engine fired up well and taxied out to the runway with no problem. After verifying controls and engine backed away from plane, started to taxi and engine died. Engine restarted easily, tested again and fine, taxied and engine died.
4) Took cowl off plane and taxied around field for 10 minutes no problem.
5) Put cowl back on taxied out to fly and engine quit again.
6)Club member familiar with small gas engines checked and cleaned filter on carburator, set low and high screws, all working fine.
5) Taxied out again and same result, engine quit. At one point it was quitting if full up elevator was applied, throttle advanced and then brought back to idle but does not happen now.
6) Got frustrated and gave up for the day.
7) Got plane out last night, started engine, tested engine, no problem, taxied around property, again no problem.
Don't think it is a fuel supply problem as when I go to restart the engine after it quits it starts right away without priming.
9) Not sure what to do as I don't want to go back to field and go through the same thing all over again.
Any suggestions on things to check or do would be appreciated.
|06-17-2008, 05:41 PM||#2|
RCC Junior Contributor
I am: Jeffrey T
Join Date: Mar 2005
Location: Ottawa, Ontario, Canada
Feedback: 1 / 100%
Total Props: 0
Re: MVVS 26 Engine Cutting out Unexpectedly
I wonder if it could be your cowling that causes the problem. The carb has a hole in the diaphragm cover that regulates fuel with static air pressure. The air rushing into your cowl on taxi increases the pressure and potentially starve the engine. Alot of Yak pilots block the cowl opening so they don't have this problem.
I'm not sure what your cowl looks like, but if theres more intake area than vents, then the cowl may be getting pressurized.
If thats the problem, you could JB-weld a brass tube to the diaphragm air pressure hole and run a line to your fuselage.
I'm no expert, but I've done some research on this matter and have heard about similar problems.
Last edited by JeffElecRC; 07-03-2008 at 10:38 PM.
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