Draining the Carbs the Old Fashioned Way

I have the unfortunate situation where my RV-12 is hangared in North Georgia while my job's in South Florida. I try to get up there once a month for long weekends to do some flying. When I store the plane for a month or two at a time, I fill the tank with 92 octane non-ethanol mogas, pull up the fuel shutoff valve, start the engine, and run it until it stops. Herein lies my problem.

It seems that invariably, one carb runs dry before the other as the engine continues to run on two cylinders until it finally quits. During this two-cylinder run as the second carb is running dry (less than 10 seconds) the engine shakes violently. I'm concerned that all of this rough running and shaking is going to rattle something loose up there under the hood.

Does anyone else have a similar experience, or know of a better way to drain the carbs for long-term storage?

There is a chance I am wrong, but I think to store "long term" you should drain the fuel tank, add a couple gallons of avgas, run the engine and let the 100LL sit in the carb bowls.

Mogas has a shorter shelf life compared to AVGAS. but, 1 month may not hurt anything. Long term to me is 90 days +.

I have left my plane numerous times over the past 7 years for a month or two. Once for 3 months. Using non ethanol mogas as a base, I have either used stabil or 50% 100LL. Never a problem. Never ran the carbs dry. Carbs are clean. Runs fine.

So, we're I you, I would use stabil, not drain the carbs, and never worry about it.

Firm believer is stabil but I've never used it on a plane. It keeps all my yard stuff from gumming up. I'm not sure I would leave the floats empty either. Might be more problems with stuff drying out. An idle cutoff doesn't empty the float(s).

sandpiper said:

I have left my plane numerous times over the past 7 years for a month or two. Once for 3 months. Using non ethanol mogas as a base, I have either used stabil or 50% 100LL. Never a problem. Never ran the carbs dry. Carbs are clean. Runs fine.

So, we're I you, I would use stabil, not drain the carbs, and never worry about it.

Click to expand...

A better produce than "stabil".....(old technology), is Startron.... Stops phase separation. Can store ethenol gas up to 2 years....not that I would in my plane. But for 3 to 4 months...no issue!

It's pretty easy

If I need to be away from a Rotax 912-powered aircraft for a long time, I usually just drop the float bowls and toss the fuel into the tank. It is quick, easy and the only tool you need (after uncowling) is a small screwdriver to use as a lever since my arthritic fingers can hardly snap the wire bail free from under the bowl.

When it is time to go flying again, I fill the float bowls from a fuel drain, snap the bail back in place and fire it up.

Have fun on your weekends off!

WBK