Please Help

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uscgflorida

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Update-Please Help

Ok, This is my first post but I have been on here reading everyday for the last month and a half. I have a Savage x 4.6 with a motorsaver air filter and an HPI polished pipe off an XL. 3/4 gal of fuel through it. I have sealed the whole carburetor, the pinch bolt and the back plate. My problem is when its running it drives by its self, Or when I pick it up it revs a bit and the wheels turn at like 10 mph. My tune is perfect. Nice line of blue smoke, but no too much. If I richen up my lsn it just stall or runs like crap. So I know its not that. What could it be? It has every symptom of an air leek but from where? My brother raced buggy's for 5 years and hes stumped. It did this since new, that's why I sealed it. Sorry for such a long post, I just wanted to give all the details.
 
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Yes idle screw is set at 1mm and the trim is set correctly. The carb slide is shutting all the way when I let off the controller.
 
I replaced the fuel lines and checked the tank, no leaks.
 
Sorry, what I meant was the carb return spring is pulling the carb all the way back when I let off the throttle.
 
hmm sounds like everything i could come up with has already been said but i wanted to take the time to welcome you to the forum,and I'm hoping maybe someone else may have some ideas as I'm stumped on this one..........

P.S. YOU NEVER HAVE TO APOLOGIZE FOR ASKING QUESTIONS HERE MY FRIEND THATS WHAT ALL OF US ARE HERE FOR SORRY I COULDNT HELP!!
 
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I installed a nova cooling head and the screws are tight. I put a second exhaust spring on to make sure it wasn't leaking. Damn I'm stumped.
 
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I replaced them too. My lhs sold me HPI-15241(HPI Dust Protection & O-Ring Complete Set) I replaced all o rings and the dust protector on the carb slide. This did not work so I pulled the needles out and put RTV silicone sealer on the o rings. That's what I used on the carb and back plate also.
 
I just checked to see if the clutch bell spins freely and it does, there is no resistance without it running. could the clutch shoes still be bad? It did this since i broke the motor in. Is there a front seal behind the flywheel that could have an air leak? How would I seal it?
 
is there an how to. that's one thing I haven't messed with. how do you remove the flywheel? and how do you know if the bearing is bad or leaking?
 
I would start the tuning process over again. Put the needles back to flush get it running, warm it up and start tuning the HSN first then the LSN. Oh by the way what are you running for fuel and glow plug? Brand, nitro content, oil content?
 
I got a similar problem with my truck, I've put an STS D28m with the clutch that I had on the 25.

The carb gap and everything mentioned here seems correct, I think the clutch springs are bit weak on mine, I'll have them replaced soon with the 1mm ones and see if it still engages the clutch at idle....
 
i think i read your using a pipe off the xl, is that the same hpi polished that comes on the savage x ss or is it a specific one for the xl? if its a different one could it do that? I'm just grasping at straws for ya as i have never owned a xl..
 
First off, welcome to the forum!

Did you have this problem before you switched out the cooling head? There are some brass washers that sometimes like to stick to the head button, make sure those are there. Have you checked temps? Typically with an air leak you may notice a loss of power through the entire rpm range and temps will definatly spike up. Other than that, if you cant figure it out, give HPI a call. Depending on how long you have had it, it may be covered under a warranty.
 
This is just a thought. you said that you have a nova cooling head. I have heard and think read somewhere on this site that they use a denser alu, then any other cooling head. I believe it is 7170 or something like that. from what I read this will pull more heat away from the mill making you think that you are not up to temp. Which in turn will cause you to lean out the mill more then you really should. I would test this if you still have the stock cooling head. Put it back on run it up to temp and see if there is a difference. This could be making you run at high RPM at idle causing your clutch to engage. again, just a thought.
 
Savage01085: I have put the needles back to flush and started the tuning posses over more time than I can count. I am using A mc9 glow plug, O'Donnell high performance 20%

Donshl: I don't think its the clutch because when I pick it up it will rev up. If it was the clutch engaging at idle it wouldn't cause it to rev would it?

SADSACK: I'm not sure which pipe come on the x ss. Is the one off the Xl the on that everyone refers to as the HPI polished pipe thats good to us on the x 4.6? Or is it a different pipe?

AllanQ: Yes I had this prob before switching to the Nova Head. There are 4 brass washers on the button head. After brake in I was seeing 300f, Thats why I sealed the carb and back plate. All yesterday I was seeing 225f to 240f. The temp outside was around 75F.

Magoo: I have not been tuning to temps but have been checking them often. You are right about the Nova head, It does extract a lot of heat away from the mill. I put the stock head on and was seeing 250f-255f then I put the Nova back on and was seeing about 235f. If I richen the lsn up any the wheels will slow down quite when its off the ground but it runs like crap when driving.

I just want to thank all of you for your help. I have never got this much help from any forum I've ever been on.
At this point I think I'll e-mail Hpi and see what they say.
 
ya I'm not sure if there the same or not but probabally not your problem anyway, let us know what hpi says as it could help others having the same problem and again sorry i coudnt help more...........
 
1mm is just the starting point for your idle gap you need to back that down till it idles lower if your tune is good and you should not have a problem. Make sure that the linkage is set to close the carb with a little pressure at nutral position as well. Doesn't sound so much like an air leek to me I think you have a simple fix here that frustration has caused to grow. Good luck.
 
The Pope: 1mm was the starting point. Like I said the idle is where it needs to be. It idles nicely. The linkage is set perfect. At this point I don't think it is an air leek but something is deff not right. My brother has alot of experience racing and tuning and he is stumped. But I really appreciate you trying to help.
 
try this,,, Start it get it to idle then w/o giving it gas push on the slide and see if you can make it stall.

As far as the front bearing goes it does NOT seal out air. this is a myth. if it is bad (bearing gone itself) it can make a leak but the rubber on the outside of the Bearing can not be there at all and you will not get a air leak. Just FYI and a direction people my push you.
 
Hmm that reminds me, my idle gap is set to 1mm as well, maybe i need to back it down it a bit after running in my engine... BTW, is it CW or CCW to reduce the idle gap?

Thanks
 
UPDATE: After tinkering till 2am this morning. Tightening everything, and scratching my head. Well today I took it out and had the same problems. Got it home and pulled the motor and took the clutch bell off and guess what fell off the flywheel? That's right a clutch shoe. The spring is broke in two, and the shoe is worn 50% more than the other two. Could this be my problem?
 
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