OS 105 HZ-R tuning issue

[777ER]

Hi,

I have a OS 105 HZ-R with an hatori SB-22FH exhaust, I'm having a problem where I do wide open throttle punchout for more than 2 seconds, the engine quits.

Running bryon rotor rage 15% fuel, mid open out about 3/4ths turn out, high almost 2 turns out.

I do the full throttle punchout from 2 ft above the ground and about 2-3 seconds later the engine quits and I'm forced to do an auto every time this happens.
It's putting out good white smoke which I'm sure it's a rich mixture, but leaning it a few clicks didn't do much.

It makes a woof or a puff sound as it quits...could be the sound of the drivetrain unloading.

I decided not to push my luck and packed up for the day.

Glow plug looks shiny and like new...even changing glowplug doesn't help. It's an Enya #3 hot plug.
Before I had a OS #8 plug in it but it quits everytime I get it up to hover.

Engine isn't hot...cool enough I can hold my finger on the cyl fins.


Does anyone know what is causing this? I'm thinking rich mixture putting out the glowplug but would seek advice before I go out and do it again as I'm trying to tune it per Tim Jones' guide.

[marc8090]

Is there good pressure in the tank after a flight? What you are describing I have seen be related to a stuck or backwards check valve. It will run in a hover but stall at full throttle.

[777ER]

Originally Posted by marc8090

Is there good pressure in the tank after a flight? What you are describing I have seen be related to a stuck or backwards check valve. It will run in a hover but stall at full throttle.

The tank is holding good pressure...I get an hiss a good few seconds when I pull the plug to vent the tank before refueling.
Check valve is in the right position...have a extra check valve on hand to see if it's a bad one.

So far I'm suspecting bad fuel filter and have a new one on order along with KSJ fuel line holder to secure my fuel lines like Nick Maxwell did.

[mr008]

Are you using a governor? If so which one? I would also check end points for throttle in different modes and bench test to see that the throttle servo is operating correctly. Sometimes simple things are overlooked , has happened to me plenty of times.

[777ER]

Originally Posted by mr008

Are you using a governor? If so which one? I would also check end points for throttle in different modes and bench test to see that the throttle servo is operating correctly. Sometimes simple things are overlooked , has happened to me plenty of times.

I'm using an CGY-750 with gov but the governor is off the whole time for tuning reason. The low idle limit and high limit has been set in the governor menu and been verified to work good, even linkages are set up correctly.

[dchekas]

2 turns out on the 1.05HZ-R on 15% is pretty rich.

I would lean about a half turn and see if that improves it.

What shims do you have in the head?

[777ER]

Originally Posted by dchekas

2 turns out on the 1.05HZ-R on 15% is pretty rich.

I would lean about a half turn and see if that improves it.

What shims do you have in the head?

It has the stock shim for 15% nitro. I'm hesitant to lean it out.

[marc8090]

If the governor is set up correctly there is no need to tune with it off. Mine are on 100% of the time starting with the very first liftoff of a new engine.

[dodgeboy]

2 turns is very very rich on this motor. mine is super happy and rich at 1/2 on my mid and 1 turn out on the high