Fuel running out of OS 105 carburetor

[guyguerra]

I posted this is the motor forum but got no responses, so I've put it here.
I am breaking in a new OS 105HZR motor on my Gaui NX7. Today was the 8th flight I've done. I landed after the first flight and was going to check the temp of the motor. The motor died on its own before I could get to it. When I walked up to the heli I saw that fuel was fast dripping out of the carburetor intake. I had to take the glow plug out 4 times and spin the motor to get the fuel out. It finally ran again.

What would cause fuel to run into the carburetor after the motor is off?

Some side notes. When I got the motor I left the needles at factory settings (I didn't verify they were correct) as the last 105 I bought had the needles set correctly. When I first ran this one I thought it was lean, and checked it. The High needle was only out 1 turn and the mid needle was out about 1/2 turn. The manual calls for 2 1/2 turns on the high needle and 1 1/4 turns on the mid. I set them to that, which seemed pretty rich, then after 5 flights I started using my temp gauge and dialed the high back in to about 2 turns to get 180 degrees. I live in Florida and did this last week in Florida weather. I am now in north Georgia and its much colder and 2000 feet higher. I had trouble holding idle so I turned it back to 2 1/2 turns on the high.

Could there be a problem with the needles, which would have caused the factory to have them closed more than what the manual says?

Does a 2000 ft elevation require a different adjustment?

[dchekas]

The regulator is leaking. It has nothing to do with needle settings.

Either some trash has gotten caught between the stop valve and the regulator body, the stop valve is gummed up and stuck, or the sealing surface machined into the regulator body is rough and not allowing the rubber tip on the stop valve to seal against it.

You can try disassembling the regulator and cleaning it out. If the problem persists, return it to Hobby Services and they will likely replace it. Do not mention you disassembled it when returning it to them though

[jiminator]

Elevation does change things. Where I used to live and fly was from sea-level to 500ft above sea-level depending on the field. Now where I live its between 2400 to 2700ft elevation. Found, on average, that I've had to open the needles about a half a turn each to get it running right. Also opened up the idle adjustment an 1/8 of a turn. On my OS 1.05hz I had to go from the manual recommended 2 turns out on the hi and 1 turn on the mid to 3 and 2 before it ran somewhat close to right. Maybe try a half turn more than the manual recommends and see how it is?

[guyguerra]

I was wondering about that. I pulled the fuel filter and it was clean, and the motor is new so I was hoping that wasn't the problem. It started up great yesterday but I couldn't fly due to rain. The tank was only 1/3 full, and I wondered if the lower elevation of the fuel in relation to the regulator is what helped yesterday. I'll fill it today and see if it happens again when the fuel level is above the regulator. Thank you for your help,
Guy

[guyguerra]

Well, I ran 6 tanks of fuel today and everything was perfect. I have leaned the motor almost a 1/4 turn, and its running great. I don't have an answer for why the fuel ran out of the carb but after I blew all the fuel out it hasn't done it again. I was getting worried as this is the second motor that I've had in this heli. The first motor was perfect and consistent, but after 40 flights or so, I forgot to put the fuel plug back in the line to the top of the tank. The motor ran lean and with being new to nitro, I didn't notice it in time. This motor did good for the first flights, then the overflowing happened Sunday and I was worried that this motor was going to be a problem. I have heard so much negative about nitros, but aside from my own error, and the one unexplained fuel flow problem, this has been a joy to fly. I ran it very thorough today and it really flew nicely.

[Yuppyflyer]

I've had this issue of fuel pouring out now and again. It is always the spring and lever in the regulator sticking. A quick strip and reassemble cures it for a while.

[racer713]

Originally Posted by dchekas

The regulator is leaking. It has nothing to do with needle settings.

Either some trash has gotten caught between the stop valve and the regulator body, the stop valve is gummed up and stuck, or the sealing surface machined into the regulator body is rough and not allowing the rubber tip on the stop valve to seal against it.

You can try disassembling the regulator and cleaning it out. If the problem persists, return it to Hobby Services and they will likely replace it. Do not mention you disassembled it when returning it to them though

Thank you for the info.....

I have same motor, and it is my 1st HELI period..... Trex700N LE Flybar
Mine has been flawless except when I had some loose bolts due to not enough locktite, or non at all.... caused some foaming of fuel...caused a lean run with 1/4 tank left.... 1gallon through and I am starting to lean it out..... Great running engine.... I have found that at 2.5 and 1.5 the engine didn't need much leaning on the MID.... It was the Idle that needed VERY LITTLE leaning out.... and 4 clicks or sow on the HIGH end....

I have the stock head gasket, and added the Thick gasket as well..
Running WildCat 20/20 YS fuel.

I may pick up some syn. and add some more to make it 30% oil..
will see...

[racer713]

Originally Posted by guyguerra

I posted this is the motor forum but got no responses, so I've put it here.
I am breaking in a new OS 105HZR motor on my Gaui NX7. Today was the 8th flight I've done. I landed after the first flight and was going to check the temp of the motor. The motor died on its own before I could get to it. When I walked up to the heli I saw that fuel was fast dripping out of the carburetor intake. I had to take the glow plug out 4 times and spin the motor to get the fuel out. It finally ran again.

What would cause fuel to run into the carburetor after the motor is off?

Some side notes. When I got the motor I left the needles at factory settings (I didn't verify they were correct) as the last 105 I bought had the needles set correctly. When I first ran this one I thought it was lean, and checked it. The High needle was only out 1 turn and the mid needle was out about 1/2 turn. The manual calls for 2 1/2 turns on the high needle and 1 1/4 turns on the mid. I set them to that, which seemed pretty rich, then after 5 flights I started using my temp gauge and dialed the high back in to about 2 turns to get 180 degrees. I live in Florida and did this last week in Florida weather. I am now in north Georgia and its much colder and 2000 feet higher. I had trouble holding idle so I turned it back to 2 1/2 turns on the high.

Could there be a problem with the needles, which would have caused the factory to have them closed more than what the manual says?

Does a 2000 ft elevation require a different adjustment?

FYI.... I am not an expert... but I have had 15 or so Nitro rc car/buggy/truck engines (all ran for many gallons) and rc plane nitro engines

If your engine is not idling, turn the low idle needle 1-blade or less lean.
(clockwise) Do not lean the top end to attempt to get a better idle..

Did the other heli engine get wrecked ?
I would be happy to help you with anything I can...
I have had my share of mistakes....so don't give up....

How is the NX7?/ Looks fantastic!....

[racer713]

I Love flying nitro.... so far, I wouldn't want Electric...
(although I have a blade 600 Electric almost ready to go...)