Selle

Hi!

I’m a happy Danish rc pilot. At the time not so happy, because of my YS 140 DZ. The engine is mounted in a CMpro Giles 202 140. I have flown about 4 hours with the aircraft, mounted with the YS engine, and there have been no problems at all. Then, a sunny Sunday, the engine would not start. I checked the glow plug, the fuel filters, the tubes, the tank, the quick fuel valve, the fuel pump at the engine, the diaphragm at the regulator, and I checked the carburettor and the inside of the pump for dirt. Everything seemed to be normal. I concluded (by watching at the tube ) that there was no fuel, entering the carburettor. I checked the fuel line again, and nothing was stopped, and no air leaked from any tubes. I tried to let the engine suck fuel from another tank, and the problem was still there. Hmm, disappointed, I put the Giles back in the car again, and I went home. A few days later, I tried to start it up again. Now, there were no problems at all, the engine started at the first spin, and ran as it was supposed to. That day, I flew about an hour, and had no problems. Then, a couple of days later, the problem went back, and is still there. The engine can start, if it gets a few drops of fuel directly into the carburettor, but I only run at the drops it gets. The engine is not able to suck fuel. The fuel I use is with 20% nitromethane and 20% ML-70 oil. What can be wrong? I have tried 1000 things, cleaned carburettor and pump, changed plug, tubes, filters, valves and so on. A little help from you guys would be very nice (So I can become happy again )


Kind regards

Kristoffer

Flyboy Dave

My Feedback: (21)

There should be quite a bit of pressure on the left side fuel line....the line from the pump
to the tank. After the engine has run, or been cranked over for awhile, and you open that
line, it should expel quite a bit a of pressure.

Is that the case on your engine ? Is the tank being pressurized ?

FBD.

Selle

Thank you for your answer =) I´m not quite sure, that pressure is generated, after the engine has turned. As soon as i get home, i will check that. If there is still no pressure, after the engine has runned, then it may be the pump, which causes the problem? If there is pressure, but no fuel comes to the carb, it almost has to be the fuel line, that causes the problem? From the fuel tank, i have 2 lines. The one of them, for the carb of course, the other one, goes to a T fitting. The one of the tubes from the T fitting, has got a one way valve mounted, so it is only able to suck air. The other tube from the T fitting, is closed during flight. It is only open, when i fuel the plane, (to avoid pressure in the tank). And sorry for my english, i hope you understand a bit of it anyway

I´ll be back later, when i have figured out, if there is pressure in my tank, after the dingo has runned ;-)

tommy s

My Feedback: (55)

The YS DZ engines do not run on pressure in the fuel tank, they have
a fuel pump which draws fuel from the tank. There is no need for pressure
in the tank. It sounds like you may have a problem with the pump in your
engine or maybe some trash in the pump or carburetor or maybe your one
way valve is not letting in any air.

tommy s

Flyboy Dave

My Feedback: (21)

....whoops, my bad. I was refering to the 1.40 sport engine with the conventional "old
style" pressure system. []

FBD. [sm=stupid.gif]

Selle

Thats okay I wondered why it should generate pressure, and why my tank should be pressurized, cause the pump is supposed to feed it. I does actually generates a bit of pressure when you crank it over. Hmm, maybe i just have to demount the engine, and seperate the parts, which are in relation to the pump and the fuel line, and take a watch. Tommy s, i will trie your suggestions, i have only got the pump demounted, not the carburattor and the valve pushrods (the pump is driven by the one pushrod, or am i totally of track?). It can´t be my one way valve, i have tried to run without it, and the problem is still there. Damn, there is a lot more pieces in such an engine, than in a conventional 2-stroke glow engine

tommy s

My Feedback: (55)

Yes, lots of parts, that's why I've never taken mine apart myself.
Good luck.

tommy s

hondaguy

My Feedback: (1)

Try posting your problem in the YS support section.
The guys who give most of the advise are YS engine service people, and give some pretty straight knowledgable answers to problems.
Below is the link

http://www.rcuniverse.com/forum/forumid_197/tt.htm

Selle

Hey hondaguy

Thank your very much, i did not notice that a YS section was here

/ Kristoffer