I have had my Irvine .72 for seven years and it has been a real good engine. I did not fly much the past two years and it hasn't been ran much. This past Nov., I started it and it ran great. Recently I have started flying again and I got it out to fly. At the field, the motor started up, ran a few seconds and quit. It could not be started back unless I primed the carb. At home I tried to run it, but it would only run the prime out and quit. I have taken the tank out, checked it, re-plumbed it with new lines and checked for leaks, took the carb off and replaced the o ring, took it apart and checked to see if was clear. The fuel is fresh and the same I have always used. The plug is good and I checked and changed it to be sure. Still it will only run out the prime and not start back. Today I noticed the tank would appear to have air being blown into it when running off the prime and I switches lines in case they were hooked up backwards. No difference. Would anyone have anymore ideas to try or check?

Hi!
Have you checked (removed ) the high speed needle and checked for dirt???

Let me gues spasmatic.

Your electrical starter motor has a wrong rotation direction!

Cees

I pulled the carb and went completely through it and I hand start it with a chicken stick

spasmatic,

When you close the air intake with your finger, throttle full open and torque the propeller by hand (no battery on the plug!!), is there a fuel flow from tank to carburetor after about ten rotations of the prop? You have to see it in the transparant fuel line near the carb.
This is the way I prime a two stroke, so I do not use "external" fuel.

Cees

I have used the electric starter on it with the muffler exit blocked which will always pump fuel to the carb but it won't do it now. The problem I have is I can't get fuel to the carb no matter what I have tried. As stated previous, the engine seems to pressurize the tank instead of creating a vacuum to pull the fuel.

is this a 2 stroke or 4 stroke?

Spaz, is your .72 one of the red ones or the earlier Q-72 like this one, just curious thanks, Dave

PS, check that the head bolts are tight, these ones came loose once when it was about two years old. They never came loose again.

spasmatic,

You have a problem, and I did ask you to do this:


Instead of to do that I read this in the next post:


I do want to solve your problem by a step by step program, but for that I do need an answer on my question.
So my advise is try my method and tell me what you see in the fuel line, we are still in the "no tool" phase!!!!!

It is just the situation your car doesn't want to start when you turn the key and you call me . The first thing I would ask:
Switch the lights on (for a short moment!!) and look if you see light, to check the battery.
Then you call back and you say:
I did turn the starter key as I normally do but the car wont start.

And later I hear your neighbour tells you take a screw driver and ..........

We have to know if the engine wants to suck the fuel and we cannot do that the way you prime.
(after we did check if you did use the right start rotation direction.)


Cees

spasmatic;

I have to think about a joke when writing about your problem.


A farmer calls the vet and he says. “When I pull the teats of the udder of An the cow normally milk comes out but not anymore. She is broken.�
The vet says: “We will look after her.�
“Lift the tail up and ask your wife to look in the mouth of the cow.�

The farmers calls back moments later he says, “Now I did use the electric milking machine but there is still no milk.�

The vet says: “Why don’t you do what I'm saying?
The farmer says: �Why?�

The vet says: “I first have to know if the cow is blocked inside!�
“Therefore, you have to ask your wife if she sees light when she looks in her mouth and you lift her tail up!�



Have fun


Cees

This covers some questions in the last three post. The .72 Irvine is a two cycle glow engine. It was purchased from Just Engines in 2003 and is the red powder coat. I tried the finger over the carb while cranking with no fuel coming through the line. I did this with two different fuel tanks . Also I tried different fuel tank heights. I took a piece of clear kitchen wrap and secured it over the carb opening and while cranking it I could see vac pulses as it came up on compression. Today I am going to pull the carb off the engine again and hook up the tank and see if I can get fuel to drain through the carb in various configurations-different needle valve settings, no needle valve etc. to see is some how I can get fuel through it. When I had the carb off before, I pulled both needles to be sure the passages were clear. I found there is a barrel the high speed needle fits into that has two small orifices that seem to line up with the fuel line connector. The barrel was turned so the hole from the fuel line was blocked and I thought that was the trouble but it doesn't seem to be. The orientation of the orifices seem to only be adjustable by how tightly the barre assembly is screwed in.

spasmatic,

The fuel inlet tap is the first thing to check.
I would put a long piece of fuel line on the tap and open the main fuel neelde, even remove it for a while.
Then throttle full open!
Then suck the line to check you can suck air through it.
Use a long fuel line to prevent to get fuel in your mouth.

Better it is to suck with a syringe if you have, then use a short line!

No air, than the inlet is blocked.
BTW I am still in the "no tool phase". Do not take a carburetor apart before you did check this.
What about that?

See picture.

Spaz, most likely your carb is virtually identical to this one from my .72, note LS needle is even with the end of the brass nut, HS needle was set at 2.5 turns out from closed. This .72 ran perfectly at these settings.

Success!!! Hobbsy, your post did it. I was on my way to take the carb off and do some test as per Taurus when I stopped to go online again and saw your message and pictures. The settings for the needles are almost dead on. This time when I primed it and flipped the prop it ran like old times. I will need to do a little adjustment but not much. I would have never opened up the low speed needle that much if I had not seem your picture of your setting. Also the high speed needle was open more than I would have thought. You were right about the carb, it is the same as mine. Once again, I would like to say thanks to Hobbsy and Taurus for you help, this is were RCU really shines.

Good luck with your engine spasmatic, no tools required!
You did not have to take the carburetor off, you can do the test on the field on any moment there is no fuel.
One questionmark for me, why is the re adjusting (Opening) of the second needle needed? Is there tank pressure missing somewhere?
Maybe you did close is accidentally, also possible and in that case not important to know anymore,

success


Cees

Taurus, your question about the second needle, I am assuming to be the low speed needle, needing adjustment was likely to come from the initial attempts to get it started. The problem was the high speed barrel having rotated the orifices out of alignment and blocking the fuel flow. After I got the high speed needle fixed, I had fiddled with the needles and did not realize they were so far off. I did read the instructions that came with the engine and I don't think they suggested so many turns. I never counted them but I think the low speed needle must have 8-10 turns on it now.

Thanks for answering spasmatic.
Maybe interesting for you to try, prime the engine by closing the air intake with a finger, open throttle, 2 a 3 maybe 5 turns on the propeller, without a battery on the plug and you have to see fuel near the carburetor. Its a good way to dose the right amount of fuel to start. After that idle throttle position "contact" and start.
(I did read you do shut off the exhaust to prime so you pressurize the tank, don't know what can happen with the pressure in it!)


Good luck

Cees