140L "Air Leaks & Spiitting Fuel out of the Carb"
06-06-2004, 07:54 PM
#1
140L "Air Leaks & Spiitting Fuel out of the Carb"
Dave,
Had a few problems with a 140L this weekend at a Pattern Contest.
I would like to thank Bob Kane, Andrew & Tim Jesky, and Steve Maxwell for helping to get the engine running well enough to complete the last two rounds in Dayton, OH.
To be fair, the engine is out of warranty and I purchased it used with very low time last August. I was told that it had less than 10 flights and I think it's less than 1-1/2 years old.
We still have a couple of problems that I need some help with...
1) The nipples in the back, close to the Carb Body, appear to be press fit. They seem to be leaking around the nipple where it is press fit. Are they actually press fit, and what is the best fix for this? Was it a problem with the engine from a design stand point and replaced with the screw in type nipple?
2) The engine seems to spit an excessive amount of fuel out of the carb at idle around 2,000RPM.
The following was done...(We did have a idle problem we were sorting out, seems to be good now)
* Fuel is Power Master 30% DZ (used WildCat 15% w/ 18% all synthetic last season)
* Prop is currently 16x11 (Will be getting a 16x12 to reduce RPM)
* Max RPM is 9,200 (Richened up to get 8,900 max RPM at full throttle).
* Valves set at .003 inches using feeler gauge.
* Low Speed Adjust Screw and O-Ring replaced.
* Regulator Body replaced with new diaphragm and plunger.
* Flushed High Speed and Low Speed needles with clean fuel through the carb nipple.
* Removed and inspected Throttle Barrel, looked good...
* Replaced Glow Plug (OS-F)
Thanks in advance for your assistance.
Larry Diamond
NSRCA 3083
AMA 5024
Had a few problems with a 140L this weekend at a Pattern Contest.
I would like to thank Bob Kane, Andrew & Tim Jesky, and Steve Maxwell for helping to get the engine running well enough to complete the last two rounds in Dayton, OH.
To be fair, the engine is out of warranty and I purchased it used with very low time last August. I was told that it had less than 10 flights and I think it's less than 1-1/2 years old.
We still have a couple of problems that I need some help with...
1) The nipples in the back, close to the Carb Body, appear to be press fit. They seem to be leaking around the nipple where it is press fit. Are they actually press fit, and what is the best fix for this? Was it a problem with the engine from a design stand point and replaced with the screw in type nipple?
2) The engine seems to spit an excessive amount of fuel out of the carb at idle around 2,000RPM.
The following was done...(We did have a idle problem we were sorting out, seems to be good now)
* Fuel is Power Master 30% DZ (used WildCat 15% w/ 18% all synthetic last season)
* Prop is currently 16x11 (Will be getting a 16x12 to reduce RPM)
* Max RPM is 9,200 (Richened up to get 8,900 max RPM at full throttle).
* Valves set at .003 inches using feeler gauge.
* Low Speed Adjust Screw and O-Ring replaced.
* Regulator Body replaced with new diaphragm and plunger.
* Flushed High Speed and Low Speed needles with clean fuel through the carb nipple.
* Removed and inspected Throttle Barrel, looked good...
* Replaced Glow Plug (OS-F)
Thanks in advance for your assistance.
Larry Diamond
NSRCA 3083
AMA 5024
06-07-2004, 08:11 AM
#2
Senior Member
RE: 140L "Air Leaks & Spiitting Fuel out of the Carb"
Leakage around the fittings is unusual. Are you sure they are really leaking, or is it just fuel being blown about from the carb? If it really is leaking, clean it up with some acetone and run a bead of JB Weld around the base of the fitting.
These engines tend to run really wet around the carb. You might try bumping the idle speed up to 2200 or so. That should dry it up a little.
Let me know.
These engines tend to run really wet around the carb. You might try bumping the idle speed up to 2200 or so. That should dry it up a little.
Let me know.
06-11-2004, 04:55 PM
#3
RE: 140L "Air Leaks & Spiitting Fuel out of the Carb"
Dave,
I appreciate your quick response.
I did cleaned up the fitting as you stated and put a bead of JB weld around the fittings. I didn't replace the fuel lines as I wanted to verify that this was the cause for the leak. The leak is now gone.
About the carb spitting fuel. I replaced the o-rings for the needle valves and the throttle barrel seal. I also replaced the o-rings for the intake tube. I took the head off and inspected for wear. All was in good shape. After putting it all back together I had to readjust the valves. Not spitting as bad as before, looks pretty normal now.
Got it back together and spent about 2 tanks of fuel setting the high-speed and the low speed. I'm probably as close as I'm going to get at this point.
Thanks for your help...
Larry
I appreciate your quick response.
I did cleaned up the fitting as you stated and put a bead of JB weld around the fittings. I didn't replace the fuel lines as I wanted to verify that this was the cause for the leak. The leak is now gone.
About the carb spitting fuel. I replaced the o-rings for the needle valves and the throttle barrel seal. I also replaced the o-rings for the intake tube. I took the head off and inspected for wear. All was in good shape. After putting it all back together I had to readjust the valves. Not spitting as bad as before, looks pretty normal now.
Got it back together and spent about 2 tanks of fuel setting the high-speed and the low speed. I'm probably as close as I'm going to get at this point.
Thanks for your help...
Larry
06-11-2004, 05:03 PM
#4
Senior Member
RE: 140L "Air Leaks & Spiitting Fuel out of the Carb"
You will never completely stop the spitting out of the carb. There is a ton of valve overlap in these engines. It, unfortunately, is one of the prices you pay for the big horsepower.
Good Flying!
Good Flying!
