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Old Sep 06, 2014, 08:47 PM
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rrothman's Avatar
United States, UT, Park City
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Originally Posted by AA5BY View Post
A flying friend got one of the OS gas four stroke engines. He had starting problems beginning about the 3rd outing. They got worse but if once getting it running, it ran fine. It finally got to the point that it was very difficult to get the engine started. After trying everything imaginable with the fuel system, he tried an RcXel ignition and the beast now starts easily.

It was my first time to see a gas engine with ignition problems that made starting difficult but then run fine. Usually it is the other way around, an engine will start easily but not spool up or will miss at higher rpm when an ignition is balky.
Did he get an ignition from rcexl or rcxel? where did he get it, I can't find rcxel and the rcexl.com website is terrible to figure out and haven't seen any way to purchase anything directly anyway, but I saw this http://www.rcexl.com/notice/5.html which made me look up ch-ignitions.com on which I don't see anything about rcxel but I like what they're selling!
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Old Sep 06, 2014, 11:06 PM
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East Texas
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Originally Posted by rrothman View Post
Did he get an ignition from rcexl or rcxel? where did he get it, I can't find rcxel and the rcexl.com website is terrible to figure out and haven't seen any way to purchase anything directly anyway, but I saw this http://www.rcexl.com/notice/5.html which made me look up ch-ignitions.com on which I don't see anything about rcxel but I like what they're selling!
He actually borrowed an ignition from DLE-20 that was not in use.

If looking for RCexl ignitions, (not RCxel - my typo bad) I've been getting them from Agape Racing and Hobby.

http://www.agaperacingandhobby.com/
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Old Sep 07, 2014, 07:11 AM
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Tucson
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Gas normally flows out of the carb, back to the tank, when the engine is not running. As long as your air intake is open (or you have a pin hole in it, as many do) your carb is not quite airtight.

The real problem is if you get air bubbles coming from the tank to the carb.

If you choke the carb and turn the prop, then it should pump fuel from the tank. If it doesn't, then there is a problem. My opinion.
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Old Sep 07, 2014, 11:47 AM
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United States, UT, Park City
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Originally Posted by wuest3141 View Post
Gas normally flows out of the carb, back to the tank, when the engine is not running. As long as your air intake is open (or you have a pin hole in it, as many do) your carb is not quite airtight.
While it seemed like gas was flowing back due to a leak, it was I believe the ethanol expanding and boiling due to the heat build up from being idle next to a hot engine.
Since switching to TrueFuel (ethanol free) and the original pumper diaphragm, I have not had the same problem.

Quote:
Originally Posted by wuest3141 View Post
The real problem is if you get air bubbles coming from the tank to the carb.
Actually I put in a RotoFlow tank that it supposed to be air bubble free, while I still get bubbles in the fuel line, they are not severe enough to stall the engine - not even a minor hesitation.
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Old Sep 15, 2014, 11:16 AM
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well I finally had the chance to go fly it this weekend, while it ran well on the ground idle at 1900 and WOT was around 6900 rpm, something didn't sound quite right in the air. brought it down and without killing the engine, secured it and ran up the throttle again, but it sounded fine as usual. so took off again and started doing rolls when the engine stalled! barely got it back to the field where I pancaked it in the rough grass, ripping the landing gear off which put a hole in the wings and dislodged the engine/firewall from the bulkhead. been too busy so haven't pulled it apart yet for full autopsy but I strongly suspect air bubbles from the "air bubbless RotoFlow" did it in, but am thinking I may switch to electric with a Hacker Motor.
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Old Sep 27, 2014, 05:16 PM
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Finally got the plane pulled apart and put the motor on the bench. Was still getting a lot of air bubbles from the RotoFlow tank, the T-piece on the QuikFire filter (both from JLProducts) was loose again even though I had epoxied the plastic fittings to the aluminum body, but it wasn't stalling the plane. I had emailed the owner about the bubbles but haven't heard back.

So I pulled the RotoFlow and QuikFire off, went back to the old tank with Dubro Sintered Bronze filter and Sullivan Crap Trap, NO MORE BUBBLES!!! Stay away from these 2 JLProducts!

Went on to find the real reason for the stall and ultimate destruction of fuselage... see attached picture of RCExcl kill switch. This had been taped up and wrapped with foam and Velcro wrap to protect but somehow the signal and the positive wires were shorting (visible burn marks) causing the engine to stall. Ignition is now also acting up from time to time, so new RCExl kill switch and probably CH-Ignition (with Auto advance/retard which also prevents the engine kicking/firing backward which just barely happened to me for the first time)
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Old Sep 28, 2014, 09:00 PM
The Prez....... again
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United States, IA, Rockwell
Joined Jul 2011
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FWIW at least you FOUND the problem. I hate it when you can't find the smoking gun.

Ken
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