ys .61 trouble

[heliadict1212]

Hopefully someone can help me here. It is a ys .61 st2.
Hard to start and idle sucks until it gets warm then its fine, also I after 1-2 tanks my engine is covered in fuel and I have no clue where it is coming from. I pulled it apart, cleaned it up really good and checked the gaskets which seemed fine, well I'll clarify that, I pulled off the carb and disassembled it cleaning everything but I didnt touch the engine block. The compression is fine and I have tried replacing the glow plug which did nothing. During flight it is fine but seems too lack power during climb outs compared to when I first got it (second hand).
Can someone help me or has the ys 61 become an antique I should forget about and get something else? Thanks.

[whitedog]

Last week end I had a 90 size airplane engine acting up as you describe. turned out to the head bolts were a little loose. (Very little) I tightened them up and it's good now. Just a thought.

[heliadict1212]

Thank you for your response, but I just checked that and they were snug. I just pulled the engine out earlier tonight and started stripping it down again to see if I can come up with something. My lhs owner said he used gasket sealer in his ys engines and it solved a lot of his problems, I'm just worried about sealer holding up soaked in nitro. I did notice my muffler gasket wasny doing that great of a job either though so maybe that attributed to my problems. hhhmmmmm...

[DavidH]

Thank you for your response, but I just checked that and they were snug. I just pulled the engine out earlier tonight and started stripping it down again to see if I can come up with something. My lhs owner said he used gasket sealer in his ys engines and it solved a lot of his problems, I'm just worried about sealer holding up soaked in nitro. I did notice my muffler gasket wasny doing that great of a job either though so maybe that attributed to my problems. hhhmmmmm...

I flew YS 61ST and ST2 for several years. I never used any gasket sealer on any part of the engine. The muffler should mate to the exhaust port without using a gasket or sealer and not leak. If there is leakage. Take some 600 grit wet/dry sandpaper. Lay the sandpaper on a glass surface. Put some water on the sandpaper. Hold the flange of the muffler perfectly square (flat) to the sandpaper. Drag it back and forth across the paper several times holding it flat against the paper. This will give the flange a nice finished surface to mount against the exhaust port and not leak.

Where is the carb located in the fan shroud? I found out over the years that the position of the intake of the carb. If it is in the airflow of the fan shroud, that fuel can be sucked out of the carb and make a mess on the engine. This could be your problem the carb may be in a vortex of air flow and fuel is being sucked from the carb before it goes into the engine.
Also another thing could be you just have the mixture too rich and that is where the fuel is coming from on the outside of the engine.
I have experienced both of the problems above when I was using YS 61 /80 /91 engines.

Also does the tank have pressure after a flight? If it does not, there may be a leak on the tank or the check valve is sticking and needs cleaning with some alcohol. Just unscrew the check valve and remove the parts and soak them in some isopropyl alcohol. Then reassemble and make sure it is working properly.

David

[heliadict1212]

Thanks, I think you may be on to something as far as where the intake is located since I have this engine stuffed into a trex 600n. The intake dosent match up exactly with the fan shroud. The tank does have pressure after a flight though so I know all that is working correctly, what I think it is actually is the clunk being stretched out and is hitting the back wall of the tank, when I drained the tank to disassemble the engine I noticed it was hard to crank the fuel pump. I will do what you said for the muffler and shorten the cluck line and hopefully that will solve the issues. Thanks for your time guys I appreciate it.

[heliadict1212]

Well I found a worn and split oring on the hover needle valve body so I'll replace that and we'll see where we're at.