captain Hook

My Feedback: (222)

I have a problem with my 25 GT. I can not get the needle valves adjusted for mid range. no matter how I adjust them, lean or rich it stumbles or 4 cycles at half throttle. High end runs great. Idles good. mid range??????????? [&o]
Help.

Zippi

My Feedback: (10)

Thats the way mine is. It sounds a little throaty at mid-range. From what I've read, just need some more fuel through it.

Grifmode4

I purchased a Brillelli 25 gt mag afew weeks ago. I had problems with the fuel mixture while in the air popping and bubbling. It
runs good on the ground. After about 12 flights I thought the tweeting was enough. I called Scott from Brillelli and he said it was a problem with the staic hole in the carb causing it to go rich. He said the air current while in the air blowing in the static hole was doing this. Scott said that if I would tap a pressure tap at the static hole and run a hole inside the fuselage it would correct the problem.

I modified my last night and will test today. I hope it solves my problem.

grifmode4

Scott Ellingson

My Feedback: (146)

Do you still need the plate I was going to send? Also were you sure to grind the tap flush on the inside? If it isn't it will hit the diaphram and may tear it, or at the least stop it from working propperly. If anyone else is having the same problem with it running good on the ground and going to crap in the air, let me know. I will provide a plate with a tap in it. Many engines do it in certain planes. BME is known for it. They actually sell a plate for $25 to replace it. We are going to install taps on all of them from now on so people do not need to do it. Just hook a hose up if needed.

Scott

RCVFR

My Feedback: (7)

Is there some subtle reason you have chosen to post this on the ARF forum? Were the engine forums all filled up?

captinjohn

I think it is a good thing to post here...thats where RC fans are asking about this going rich problem. Best to post in BOTH forums. just my 2 cents. Capt.,

Grifmode4

After I put a pressure tap at the static hole as Scott suggested due to popping at mid throttle, I flew yesterday and found that it helped but didn't cure. I ran ok and didn't die all day but I still say it has a problem. After I put the plane in my shop I found a gas
leaking between the carb spacer (black block) and engine. Called Scott today and said this COULD cause a problem with air leak through the gasket. I'm going to replace it with new thicker one and see if it corrects the problem. The gasket between the carb and spacer looked good.

GrifMode4

Scott Ellingson

My Feedback: (146)

Anyone having mid range problems with the 25 let me know. I will be sending new intake gaskets out to the last 30 people to buy engines. (that is when we changed gasket material) After talking to Grifmode4 on the phone I am convinced the problem is a new thinner gasket material we have been using. I believe that as the engine is run a few times, the intake can warp slightly causing a leak in the intake. We sent out over 100 engines with thicker intake gaskets before and did not have this trouble, so I believe this will fix it. I think the thicker gasket can compensate for the slight warp were the thinner gasket can not. An air leak can be compensated for on the H and L side by adjusting the needles. But the mid range will still suffer and be lean. It also makes for a hard to tune engine. I will start sending them out tomorrow morning and if you don't get one and need one let me know. I am very sorry for the trouble. Never thought a 2 cent part could cause a problem Grifmode4 will let me know if this cures his problem, but I believe it will. I will also inclyde a new carb gasket. no need to reuse the old one.

Thank You,
Scott Ellingson

Grifmode4

I put a another gasket between the carb block and engine due to a small gas leak seeping through (very, very small). With Scott's suggestion I used a asbetos-free fiber material with a thickness of 0.040 inch. I ran the engine on the ground with a apc 17 x 6 prop. I had to readjust the l/h needles and got it to around 2100 rpm and high at 8100 rpm. I continue to punch it and l to h was smooth. I had to tweek the low end 1/8 rich and now when you go in mid range, it will sputter for a second then even out.

GrifMode4

Grifmode4

After the gasket issue was resolved, the Brillelli 25cc mag has been running "Perfect". No midrange problems, just running smooth as silk, at any throttle position. I couldn't ask for a better engine for my Ultra 120. If your looking for a economical engine, Brillelli is a good choice.

Engine installed on: Ultra 120 wt 13.5 lb apc 17 X6 2100 rpm idle 8200 rpm hi after the 15 flights I use Mobil 2t 2 cycle 60:1
16 oz tank with 1/8" tyron fuel line --- flight time on the tank is approx 25 min.
Idle needle position is 10 o'clock Hi needle position is 2 o'clock
With a thicker gasket between spacer and engine corrects the air problem.
If you use Du-bro 16 oz tank with 1/8 tyron, don't use the brass tubes that goes with it. It fits ok
but it will have air leaks. Drill out the plastic connector and fit a 1/8 tube.

GrifMode4