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Old 08-16-2009, 04:59 AM   #1
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Default My buggy won't idle, help please

Hey guys, I'm trying to figure out what the problem is before resorting to buying a new engine
I have a Kyosho MP777 with an OS .21 VG Pull-Start

I've run somewhere between 1 and 2 gallons of fuel in this engine, it's not too old. Right now, it struggles to start I have to gas the throttle to get it to idle. Then the engine wants to race like crazy, and if I change the the low-end and idle settings it won't idle, it either wants to go, or nothing. And even if I get it to run, the motor dies in less than a minute.

I removed the air-filter, and noticed bubbles in the fuel inside the carb, and also air bubbles inside the tube that goes from the pipe to the fuel tank. I have tried 3 different pipes (stock, dynamite, and ofna) with the same results, so I know it's unlikely to be the pipe, I have tried different needle settings, and had other racers at the track try different settings too, but still air bubbles in the fuel, and exhaust tube and no smooth idle. I also checked the heatsink screws and the pull start screws on the back, everything seemed tight. One guy said it could be the fuel tank, but I don't see how, another guy said it could be the pull-start which is an air leak to begin with, I could remove it and attach a backplate, I do have a starter box. Is there anything else to try before installing a new engine? Does anyone have any ideas, experience, or suggestions before I shell out $200+ on a new engine?
Thx!
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Old 08-16-2009, 05:05 AM   #2
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try a new plug... os p3
replace yr fuel tubings and start tuning from stock settings.
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Old 08-16-2009, 05:11 AM   #3
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+ 1 on the stock settings and if your fuel tank is cracked you could be getting air there
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Old 08-16-2009, 05:44 AM   #4
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A vg can't use a p3. Try a new plug. If that don't contact hobby services, vg has a 2yr warrenty. I had to have mine rebuilt around 2 gallons. They will do it for free.
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Old 08-16-2009, 06:12 AM   #5
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oh ya...p3 is turbo plug, try a os #6.
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Old 08-16-2009, 06:30 AM   #6
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Wait a minute, bubbles in line from pipe to fuel tank? fuel sloshing into line while making right turns usually. that will give a "false lean" setting.Saw an article about that and the solution was to put a loop of line and mount it to the right side of the tank, I believe. Time to go back to basic settings for sure. Set the idle gap on carb to .7 to 1mm to start.Go back to factory settings and the lean the lsn about 1/2 turn(usually factory settings are real rich) Also make sure the servo is holding the throttle closed at idle setting. Easy to bump epa sometimes and end up with a servo that is holding throttle open just a bit. And like they said, get a new glow plug. If its been in for more than a gallon it may be due. And of course make sure the carb is sealed at the neck where it enters the block. Air leaks cause more grief......
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Old 08-16-2009, 11:28 AM   #7
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Quote:
Originally Posted by revo61 View Post
A vg can't use a p3. Try a new plug. If that don't contact hobby services, vg has a 2yr warrenty. I had to have mine rebuilt around 2 gallons. They will do it for free.
what do they ask you for? Original box upc symbol, sales receipt? I have to dig for those.
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Old 08-16-2009, 11:59 AM   #8
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http://www.hobbyservices.com/
I think you will need the receipt.

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what do they ask you for? Original box upc symbol, sales receipt? I have to dig for those.
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Old 08-16-2009, 03:18 PM   #9
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Befor you send it back I would do a couple things. First set carb back to factory settings. If you don't know them then go out 1 full turn on each from where they are now. This will get you so your at least not too lean. Next take your engine and gas tank out and check for leaks by putting them in a pot of water and using some fuel line blow into it and see if there are any bubbles .
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Old 08-16-2009, 04:36 PM   #10
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I just spent 3 hours trying your guys' suggestions. I changed the fuel tubings, and even experimented with different tubing lengths, there was of course no pinching or anything, the body was off. I tried a different fuel tank, and I again tried both my Ofna and Dynamite pipe. I also removed the carb, wiped everything off, and carefully reinstalled it exactly right, being mindful that the idle screw attached correctly, and the rubber stopper was on just right on the neck of the carb before tightening everything. I tried factory settings, extra rich settings, messed with the idle, tried to open the throttle more, and also less.. The results were the exact same, bubbles in the carb, and the engine has to either rev big, or stop, nothing inbetween, nothing close to an idle... Can someone explain how to check for and patch air leaks in the engine, I don't understand the boiling water and soapy water method, and how to fix a leak. and btw, and I can't find my receipt to send it back to OS.... unless someone has one more "Hail Mary" idea, I guess it's time to hit the ATM and get a new motor ....
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Old 08-16-2009, 04:49 PM   #11
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Where did you buy it from, most websites keep a list of orders you have made. I had get one from lhs. I told them the aproximite time I got and they were able to find the transaction and print it.
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Old 08-16-2009, 04:58 PM   #12
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Quote:
Originally Posted by revo61 View Post
Where did you buy it from, most websites keep a list of orders you have made. I had get one from lhs. I told them the aproximite time I got and they were able to find the transaction and print it.
That's a real good point. I got mine from Ultimate Hobbies in Orange County, they have a computer system that saves every purchase customers ever make, they can even give you the bad news of how much you have spent there
I Have to stop by there tomorrow to pick up parts for my TC3 so I will ask for a reprint of the receipt, maybe then can produce it and I can get my warranty service from O.S. again thanks for the input, I'll give it a try.
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Old 08-18-2009, 02:08 AM   #13
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I'm going to search for airleaks, replace the pull-start with a backplate, and then if still has problems, take the whole engine apart, check the piston, and every single part. 2 years ago I would just buy a new motor, but with the economy and all ...
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