'finger' test on a YS50

[whaleboy]

Sorry if this is a silly question, but... I've read about putting your finger on the backplate of the engine to gauge the temp, but I'm not entirely sure where to do that on a YS engine. The backplate (assuming I'm thinking of the actual backplate) is very recessed and has a fuel tube in the way (to pressurize the tank), so there is no flat surface area to touch. Do I just touch the thin outer edge of the bottom plate, or the middle of the cylinder wall where there is more surface area to feel?

Thanks

-David

[george0079]

The "Finger on the backplate" test really doesn't work on the YS engines. The pinch test, and lidtening to the engine is the best way. And a temp Gun...

[whaleboy]

What is the pinch test? And I assume you mean listening to the engine? Since this is my first nitro, The only way I could tell its not tuned right by ear is if its sputtering. I do have a little IR thermometer. Where should I take a reading and what temp should it be? For break-in as well as after...

Thanks

-David

[TheBum]

The pinch test is for setting the low end needle. After the engine warms up, preferably after landing after a flight, leave the engine idling and pinch the fuel line shut about 1 inch from where it enters the carburetor. The engine should speed up after 2 seconds and then die. If it dies right away, your low end needle is too lean. If it takes much longer than 2 seconds before it starts speeding up, the low end needle is too rich. Having the engine up to operating temperature when you do this is imperative.

[whaleboy]

I ran a couple tanks yesterday. I have a feeling I was running on the lean side, as I had plenty of power, no bogging at all... If I was running on the rich side, should I have had a bit of bogging? This thing had much more power than my 500 for sure (500 is running a 12t pinion though...). I also timed the second flight and landed at 7 min... tank was still half full. My temp gun was not working that well as it was showing temps of 110F or so a couple min after landing... it was definitely hotter than that at the time of reading... not sure what I was doing wrong. Anyway, the engine felt good. I had a guy at the field helping me out, and he adjusted the main needle to about 1 and 1/3 out and after seeing me fly said it was rich and was fine for breakin. I still think it wasn't that rich, but I have 0 nitro experience, and he did (although he had never run a YS before, but was thinking of getting one).

Anyway... After the second and third flights (1/2 tank each), I had fuel leaking all over the place. I checked and tightened some motor screws, but it looked like it was coming out of the carb. Both of those last two flights the engine died after landing, and I probably forgot to clamp the fuel line, so the question is... If I do forget to clamp the line to the engine, will the tank pressure force fuel out of the carb and all over the place? I was thinking I had a leaky engine, but after taking it out last night, I realized that it was probably not a leak at all and just the tank pressure making the mess. I need to get in the habit of clamping that line right away.

-David

[WayneBrown]

Originally Posted by whaleboy

I ran a couple tanks yesterday. I have a feeling I was running on the lean side, as I had plenty of power, no bogging at all... If I was running on the rich side, should I have had a bit of bogging? This thing had much more power than my 500 for sure (500 is running a 12t pinion though...). I also timed the second flight and landed at 7 min... tank was still half full. My temp gun was not working that well as it was showing temps of 110F or so a couple min after landing... it was definitely hotter than that at the time of reading... not sure what I was doing wrong. Anyway, the engine felt good. I had a guy at the field helping me out, and he adjusted the main needle to about 1 and 1/3 out and after seeing me fly said it was rich and was fine for breakin. I still think it wasn't that rich, but I have 0 nitro experience, and he did (although he had never run a YS before, but was thinking of getting one).

Anyway... After the second and third flights (1/2 tank each), I had fuel leaking all over the place. I checked and tightened some motor screws, but it looked like it was coming out of the carb. Both of those last two flights the engine died after landing, and I probably forgot to clamp the fuel line, so the question is... If I do forget to clamp the line to the engine, will the tank pressure force fuel out of the carb and all over the place? I was thinking I had a leaky engine, but after taking it out last night, I realized that it was probably not a leak at all and just the tank pressure making the mess. I need to get in the habit of clamping that line right away.

-David

oh yeah, clamp and pull the line off the one way valve as soon as you land...

[whaleboy]

Originally Posted by WayneBrown

oh yeah, clamp and pull the line off the one way valve as soon as you land...

Live and learn. . Is there an easier way to relieve the pressure rather than reaching under the heli (quite awkward) and pulling the line? I figure a T connector on that line with a simple clamp, but the only T connectors I see have fuel filters in them. Can someone point me to just a plain T connector without the filter?

Thanks

-David

[WayneBrown]

Originally Posted by whaleboy

Live and learn. . Is there an easier way to relieve the pressure rather than reaching under the heli (quite awkward) and pulling the line? I figure a T connector on that line with a simple clamp, but the only T connectors I see have fuel filters in them. Can someone point me to just a plain T connector without the filter?

Thanks

-David

I don't want to see or hear of you doing that. It adds a failure point on a pressurized system where you don't want or need one.
Simply reaching under the heli is best.
There really is a reason YS states a specific length of tubing from the pressure fitting to the check valve, and is the reason the engine comes with one pre-cut in the box.
Please keep this as simple as you can, even if it's awkward.

[whaleboy]

Originally Posted by WayneBrown

I don't want to see or hear of you doing that. It adds a failure point on a pressurized system where you don't want or need one.
Simply reaching under the heli is best.
There really is a reason YS states a specific length of tubing from the pressure fitting to the check valve, and is the reason the engine comes with one pre-cut in the box.
Please keep this as simple as you can, even if it's awkward.

I guess I could disconnect the line at the top of the tank rather then at the check valve, which is completely underneath the Heli...

-David

[heliadict1212]

Originally Posted by whaleboy

I guess I could disconnect the line at the top of the tank rather then at the check valve, which is completely underneath the Heli...

-David

thats what i do.

[whaleboy]

Originally Posted by TheBum

The pinch test is for setting the low end needle. After the engine warms up, preferably after landing after a flight, leave the engine idling and pinch the fuel line shut about 1 inch from where it enters the carburetor. The engine should speed up after 2 seconds and then die. If it dies right away, your low end needle is too lean. If it takes much longer than 2 seconds before it starts speeding up, the low end needle is too rich. Having the engine up to operating temperature when you do this is imperative.

For this 2 second rule... I've got it to where if I clamp the line, it will idle normal for about 2 seconds, then speed up and eventually die. Once it starts speeding up, it can take 5 or so seconds to die. Is this ok, as long as the normal idle is around 2 seconds?

-David