rgoldy

Turn back a couple years ago and I am flying a Brison on standard pump gas and after many flights, plane goes splat. So the engine has sat a couple years. Revive the engine in a new plane this year-everything in the plane is new, have not changed anything in the engine. Go to start and it actually started really quick and ran pretty good-for a while then started running crappy with no revs.

Analyzing..took the feed side of the carb off and there is like jelly in it clogging up everything (not a little bit but a bunch). Let jelly dry and it does pretty quick and it turns to a white powder. Note that the tan fiberglass-like diaphragm that is there has been stripped of its covering so it is presumed that is what the white powder is.

So-thinking to myself that this is what they mean by running gas with methanol does. But here is the kicker-this year I switched to methanol free gas. So does this mean that because I switched to methanol free gas, that I am going to have to rebuild all my carbs or is something else going on? The only other planes I have flown/started this year either are brand new or I have put a new carb on so this is the first I have seen anything in a "non-new" condition.

Gizmo-RCU

My Feedback: (27)

Clean and re-kit the carb and you should be good to go. Real common for the carbs to do such after sitting that long, nature of the beast.

nmav8r

I use100 LL no difference in performance but starts and smells better. Cost a little more but still cheaper than nitro.

rgoldy

Rebuilt and back on plane. Lunch is over so out I go to give it a whirl. Let you know....

rgburrill

Sounds like you use Shell gas. It did that jelling crap in my Ford Aerostar.

CK1

My Feedback: (60)

Ethanol eats away and stiffens the rubber parts over time Ethanol free gas will reduce damage caused by ethanol but will not stop damage caused by the other compounds / agents that are added to the fuel . As the gas evaporates it leaves behind deposits of the agents in the form of a thick goo or powder depending of the fuel blend used . So using ethanol free gas will not completely remedy the need to occasionally rebuild your carb after setting for long periods .
Rebuild the carb and keep flying .

rgoldy

All is well and we are running good. Only thing now strange is the carb settings. Brison's have a strange high end setting as it is (about 3/4 turns is all) and I am down to 1/4 turn. But is runs great so stop questioning and fly it.

rgoldy

Another note-if you are soaking your carb in acetone, remove the pulse needle first. Acetone eats the little seal at the end.

CK1

My Feedback: (60)

Check the metering lever height it may be too high or you may have the gasket on the wrong side of the diaphragm. The gasket goes against the body of the carb and then the metering diaphragm then the cover . These are the two most common causes of overly rich condition that necessitates a lean needle setting. The third reason would be that the needle valve has been overtightened at some point and openened the needle seat too much.

Truckracer

My Feedback: (19)

+1 on the above! My bet is the gasket being on the wrong side of the metering diaphragm.

av8tor1977

My Feedback: (6)

Yep.

AV8TOR