Hello all,

I have a Brison 2.4, running on 40:1 Red-Line Synthetic racing oil, 20X8 Xoar prop. Until yesterday it was bullet prove.... Yesterday for the first time (5 gallons of fuel) I had 5 dead sticks in a row. It seems that while on the ground it runs great, but in the air it will die if you try to idle it, especially coming out of a dive, when you add throttle, it will die. I tried changing the fuel mixture and made no difference... The only factor that has changed since I flue it last was the ambient temperature - it was about 20 degrees cooler yesterday. Any one has any ideas what might be going on with it, or similar experiences?

Possibly water in the fuel caused by condensation, but not likely. Don't know how you have things filtered co check the fuel screen under the cover on the opposite side of the carb from the diaphragm. It's a very small round screen so be careful not to lose it. You'll have to pick it out of it's recess to do any cleaning. Just carefully push it back in when done. Check to be sure the fuel line at both sides of the gas tank are tight and not sucking air. Possible dirt elsewhere in the carb depending on how well the gas is filtered.

Sounds very much like a fuel delivery issue and you just need to find the cause. Good luck.

the diagram in the carb is going bad

Thanks, there is only about 30 flights on this plane so the fuel system should be ok (all connections are secured with safety wire), but I am going to remove the whole fuel system from the plane and inspect it.... I will also take a look at the screen you mention in the carb... Hopefully it will be something simple and I will not have to sent the engine in for service....

Hey 2004. I had the same problem In a way. I have the Fox 2.4 with a 20x10 xoar on an extra Klotz 40:1. This motor ran great never let me down. Not one deadstick in over 200 flights. Well Motorsports shop stoped carrying klotz. Talked around an ordered some Amsoil Saber.Mixed it 40:1 went to the field an re-tooned.Ran OK on the ground 6800rpms. Which was about 1000 less than what I had been getting. Took off an it had a burbble that was holding it back, Throttle response was normal, just lots of burbbles. Finally the first of 4 deadsticks all within 3 hours.....So I started talking to everyone asking If they had anyIdeas.Nothing.....So I went home an started reading....Not trying to start an oil war here but what I found was there are some oils that don't work well mixed at real rich ratio's.Like Saber.Now I was one of those guys who said 40:1 is a lean as I will go cause I want my engine to have some oil. Well after reading about how to much oil creats carbon behind the ring an on the piston, I started trying new mixs. Weedeater is my test bed. It was turning 6100 on 40:1 Saber. So I tryed 60:1 an it jumped to 6980. Tryed 75:1 an it turned 7300. Its a really old Ryan with the ryobi engine.....I weedeated the yard, almost a mile of fence line, then went behind the barn an ripped into black berry vines. About 6 hours of weedeating. As the day went on an I worked deeper into that 2 gallon gas can it was running better an better.All the oil on the muffler was gone,The spark plug that was always black an gummy was turning a light brown. It was starting better aswell..... I work out of town so when I was gone my wife called an asked if I had rebuilt the weedeater cause it started in 4 pulls an not 9. After getting back home I looked the piston an plug over in the weedeater. Finally I worked up the nerve to try the 75:1 in my model. It started better, I tooned it an got 7730 out of it. It does not burbble at all an has never tryed to stop in the air on me agin. I have 4.5 gallons ran throgh it sense the day of the deadsticks.......Runs better than ever............Take what you want from this. Maybe it will help

Amsoil Saber.Mixed it 40:1
I think Amsoil Sabre is a 100 to 1 mix [sm=confused.gif]

Not even going there. Oil is a non sequiter for this issue.

I've rebuilt the carb, and ran the engine still on 40:1 mix... While I did not have a chance to test it in the air, on the ground it ran great - first thing I noticed was how easy it was to start - it popped after just 3 flips and than it fired on the second flip - it used to take minimum of 10 to 12 flips on the first start of the day before... Transition seems more crisp, idle smoother... It seems to run great now, but the real test will be in the air....
Thanks all for help...