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Old 05-24-2015, 10:03 PM
Vinnie6 is offline
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Originally Posted by kerwin50 View Post
Have you mixed oils? I've seen gumming do that
No.
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Old 05-25-2015, 03:54 PM
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Quote:
Originally Posted by bluefear View Post
is it normal for fuel to spill out from the hole in the bottom of the carb during priming/flipping?
Yes!
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Old 05-29-2015, 11:17 PM
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I figured out what is wrong. Or at least I think so.

The new walbro diaphragm/gasket set came and I installed them.

Put the carb on the plane and began to fuel.

Before long fuel was coming out the muffler.

Drained the tank and checked fuel lines.

Made sure there were no kinks and began to fuel again. Again, fuel went right to the carb. At the tee fitting it is supposed to go to the tank, not the carb.

Took carb off again. Did an air test - Put a short length of fuel line on the fuel inlet nipple and tried to blow air through . Air passed right through the pulse hole. Covered pulse hole with finger. Now no air can go through.

Put carb back on engine. Did air test again. Air goes right through.

LEAKY CARB GASKET!! Air escaping through the pulse hole. It is original, and the carb has been on and off countless times through the years. I think I have been over-tightening the carb mounting bolts too.

New carb gasket on order...
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Old 05-30-2015, 02:18 AM
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Maybe I'm reading this wrong, but you should not be able to get air through the inlet by blowing whether the gasket is good or no good.

The metering side of the carb has the needle that seats a needle.
This needle usually needs around 12~14 pounds of pressure to unseat.
That is how I test my pop off pressures.

Any way you can get some pictures or something?
Maybe I'm not even close...

Bob
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Old 05-30-2015, 05:59 PM
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Quote:
Originally Posted by Vinnie6 View Post
I figured out what is wrong. Or at least I think so.

The new walbro diaphragm/gasket set came and I installed them.

Put the carb on the plane and began to fuel.

Before long fuel was coming out the muffler.

Drained the tank and checked fuel lines.

Made sure there were no kinks and began to fuel again. Again, fuel went right to the carb. At the tee fitting it is supposed to go to the tank, not the carb.

Took carb off again. Did an air test - Put a short length of fuel line on the fuel inlet nipple and tried to blow air through . Air passed right through the pulse hole. Covered pulse hole with finger. Now no air can go through.

Put carb back on engine. Did air test again. Air goes right through.

LEAKY CARB GASKET!! Air escaping through the pulse hole. It is original, and the carb has been on and off countless times through the years. I think I have been over-tightening the carb mounting bolts too.

New carb gasket on order...
Sounds like your diaphragm is not hooked to the float. There's a little notch that the nipple on the diaphragm slides into. When you put the diaphragm cover on it will then open the float causing fuel to come out when you pump it.
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Old 05-30-2015, 08:06 PM
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Quote:
Originally Posted by bob_nj View Post
Maybe I'm reading this wrong, but you should not be able to get air through the inlet by blowing whether the gasket is good or no good.

The metering side of the carb has the needle that seats a needle.
This needle usually needs around 12~14 pounds of pressure to unseat.
That is how I test my pop off pressures.

Any way you can get some pictures or something?
Maybe I'm not even close...

Bob
Bob, you are So close! You got me thinking. Know what I did? The rebuild kit is universal. There are several different flat gaskets that contain the one-way valves. There were two black rubber ones that fit. One was solid and one has a big opening in the middle. Even though the one I was replacing was sold, I still managed to put in the new one that's got the big opening in the middle. I need to show pictures. Anyway I'm confident that when I put the right flat rubber gasket in, fuel won't pass through anymore. Good grief!
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Old 05-31-2015, 11:45 AM
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Quote:
Originally Posted by Vinnie6 View Post
Bob, you are So close! You got me thinking. Know what I did? The rebuild kit is universal. There are several different flat gaskets that contain the one-way valves. There were two black rubber ones that fit. One was solid and one has a big opening in the middle. Even though the one I was replacing was sold, I still managed to put in the new one that's got the big opening in the middle. I need to show pictures. Anyway I'm confident that when I put the right flat rubber gasket in, fuel won't pass through anymore. Good grief!

The one that's solid is your diaphragm. The one with the big hole is the gasket itself. You need both of them. Like I said if you didn't connect the fork to the nob on the solid one then when you put the diaphragm cover on it will force the float to be open.
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Old 05-31-2015, 10:49 PM
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Alright - some pictures.

I think I got the wrong kit. I got the D10-WAT. The only gasket in the D10 that matches OEM is the blue plastic one. I am going to stick with the OEM and not replace it. It looks fine and the rubber one-way valves are still very soft and pliable. It's on the left with the fiber gasket "stuck" to it in picture 2.

I did replace the diaphragm with the new one from my D10 kit. It is a direct match with what came out. JHelber, there is no notch and fork on this carb. It just sits in there. I can gently push in with a toothpick through the hole in the cover and feel it make contact with the needle and then open it.

I will now try to run the engine and tune it again. I have redirected the fuel line in front of the tank, giving it a straighter shot into the engine area. However, the tank is secured with velcro and straps and nothing has been moving around.

Which leads me to think, maybe I just didn't give it enough warm-up time? It ran so good in the garage back in March. It should have run the same at the field. I only let it run a half minute or so before throttling up, it bogging, and me assuming I had problems.

I'll post again after running the engine again.
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Old 06-01-2015, 06:37 AM
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Sorry, I stand corrected then. Hope you get it figured out.
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Old 06-01-2015, 07:40 AM
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You needed K10-Wat
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Old 06-03-2015, 09:49 AM
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Update:

I put things back together and ran the engine last night. I Xipped the carb. Once one understands that the H and L needle valves affect each other, it becomes a pleasant experience getting it tuned. At least it went well for me. It is running GREAT!!!

Tonight I will fire it up again before putting the cowl back on. I want to see if it bogs for a long time at first before warming up.

Will fly this weekend weather permitting.
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Last edited by Vinnie6; 06-03-2015 at 11:09 AM. Reason: typo
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Old 06-04-2015, 10:25 AM
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I ran it again last night. Sure enough, when xipped, it takes a long time to warm up.

I moved the choke to a slider on the transmitter instead of a switch, so I can give it partial choke to keep it running after it starts.

I also slowed down the throttle advance, and put the throttle on a curve.

All these things really helped it run better.
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Old 06-04-2015, 10:32 AM
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How do you slow the throttle advance?
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Old 06-04-2015, 10:42 AM
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I think he means he slowed the throttle servo. Which shouldnt have to do.

What does Xipped mean?
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Old 06-04-2015, 10:46 AM
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It's named for a method of tuning.
You slowly bring the throttle position from full to the spot where it starts to burble/four stroke and tune out the richness in that spot.

You continue doing that until you reach idle.
Once done, there should be not stumble or richness in the engine at all.
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Last edited by bob_nj; 06-04-2015 at 10:54 AM.
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