mattnew

My Feedback: (2)

I have a 15GX gasser that when I cut the ignition sometimes will run for 10-15 seconds after the ignition has been cut. Sometimes it will shut down fine.. it usually starts doing this 3rd or 4th flight into the day. It doesn't appear to be running to lean, however this behavior has me a bit suspicious.

Thoughts?

Thanks

Pete Bergstrom

Matt,

We haven't seen this behavior in any of our testing. I would look into the following:

1. If you remove your on/off ignition switch from the battery/ignition loop (i.e. just plug directly into the battery pack) does this solve the problem? If it does, replace your switch. if not:

2. Pull your spark plug and see if you have an accumulation of carbon on the plug. The carbon might be retaining enough heat that the engine continues to run in a compression mode (ala a glow engine.) Clean any accumulated carbon from the plug and retry to see if this solves the problem. If there is an accumulation of carbon this is a good indicator you are running the engine a bit too rich.

Pete

dirtybird

My Feedback: (5)

I use to to have a motorcycle that would do that. It was caused by getting hot and using cheap gas.

mattnew

My Feedback: (2)

Pictures are as taken out of engine... nothing touched on the spark plug.

Overall the engine runs pretty well.. I was just at the field and put another 3 flights on the engine. The only 2 things I'm trying to understand.. and I fully agree its likely a tuning issue that I'm going through.... is that I don't always get the engine to kill when I flip the cutoff switch ( I have a battery-> electronic cutoff -> ignition setup ) and also occasionally my midrange goes away.. meaning reducing throttle from full throttle to 1/2 throttle results in no change in the engine rpms.... happens maybe 1 or 2 times a flight. I wouldn't be surprised if I'm rich... I'm assuming you mean I'm rich on the low speed needle and not the high speed?

Overall the engine runs great... just a couple weird issues I'm trying to iron out in my own setup.

mattnew

My Feedback: (2)

any thoughts on the plug?

airraptor

My Feedback: (66)

lots of oil

ahicks

My Feedback: (2)

Maybe expand your end point adjustments on the opti switch channel? I don't know how your numbers run, but if one end is 100, take it out to 125? if the other is 0, take it to -25?

Point is, possibly the opti switch is running on the edge of whatever range it's looking for in this installation. Expand the available range a hair to make sure you're able to run the switch properly?

mattnew

My Feedback: (2)

thanks ahicks... that is worth a try. I have some test equipment here to check to see what the operating range is on the opto.