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Frustrated!!

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XXChAoTiCXX

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Hello everyone, it's me again. Yet with another problem.

Well this has been an ongoing problem that I just haven't mentioned specifically yet- I can't get my car tuned. I have tried all of OFNA's website ideas, and some of what I have found on this forum as well, but no luck. My car acts completely random.

I run a Hyper .21 8 port
Once I'm started, I let the car warm up to about 180-200, giving short bursts of throttle. Once up at temp, I pinch off the gas line near the carb, and count how long it takes to die. If it is more than 6 seconds, I lean the LSN an hour, if it takes less than 5-6 seconds, I richen the LSN an hour. Once it takes 5-6 seconds, I start her back up and slowly increase throttle while still on the box, watching for white smoke through the rpm range. If it is present, I put her out and run slowly back and forth a couple times, then hit it. If it seems sluggish or seems to be loading up, I'll take her in and lean the HSN a 1/4 turn and continue. Once the car seems to be at peak power, I richen it up an hour or two, and let her go. Tuned right? Wrong! Not a minute later she is stuttering on herself and making a sound that I can only relate to being way too lean. The reason for this assumption is that when she makes this sound her temps skyrocket to 230-240+. So I then richen up the HSN a 1/4 turn, and whalla-too rich to get her started again. I go back and frth like this until I am at wit's end and my battery packs are dead. I just can't find any pattern to the behaviour of my motor. I live in the Phoenix area, but now temps are perfect about 70-75F, and the air is as dry as a bone.
I use O'Donnell 20% and Hobbico ARO
No other mods other than failsafe, Rx battery and servos.

HELP!!!!!
 
alright that is what my rc10gt was doing so i figure it was sucking air from somewhere. look at the fuel lines,check the washer under the glow plug, check the gas tank(this was my culprit).
 
I must. I removed my pullstart, and filled the hole for the cord with acrylic caulking. and I should either do it again w/ silicone, or get the bump-start backplate for my .21. It totally slipped my mind that I had done that!! Thanks again guys!! Oh, by the way I looked everywhere for the Bumpstart backplate for a Hyper 8 port, and the only place I could find it was my LHS, but they want $26 for it. Anyone know of a cheaper place?
 
As long as you have good smoke coming out of the exhaust don't worry so much about the temps. If it gets to the 300 degree mark then worry. People seem to think that you can tune strickly by a temp gun, you can't. Double check for air leaks and then run it. The first 10 years I ran nitro I never even owned a temp gun, and I didn't ruin any engines. Temp guns are good for break-in and then to get you in the ball park for final tune.
 
It sounds like you have tuned it correctly, but maybe you have't allowed it to get up to temp all the way. Warm it up to 230ish then tune it how you described. If it runs great for a bit and suddenly jumps up to 270-280 then you may have a problem, most likely an air leak. Also seal the carb neck and check tank/lines for leaks.
 
Ok, I removed the pullstart body, and pulled the caulking out of the pullstart cords hole, and filled it with solder. This should be airtight. But does the absence of the pullstart spindle and cord have something to do with my lack of stability possibly, or is it that as long as I'm airtight I should run fine??
 
The pullstart should not have anything to do with how the engine runs, as long as its air tight you're set. Did you seal the carb neck? Check fuel tank and lines?
 
How do you recommend I check those for leaks? And remember, I am using the standard pullstart backplate, covered by an empty pullstart housing which is now soldered shut. Before I had it caulked shut, but I believe the fuel ate away at the caulking to create a leak...
 
The two most notoriuos places are on the carb neck and the backplate. If you dab some high temp RTV silicone sealant in those areas, you will create a thin silicone seal that helps if not prevents air leaks.

As far as a tool to us, I know there is something that can be used but I have never used it. It is just second nature to do that to all my mills that I have.
 
What I do is block one of the two nipples and blow into a line connected to the other and see if anything leaks out, theres probably better ways. For the lines I just look for little cracks in them, but again someone should chime in with better ways haha.

As long as your backplate is sealed the block, you should have no problem, although how is your starter shaft held in with out the wheel to block it from coming out?
 
You're right, I have no idea. For all I know it may come out a bit till it hits the inside of the pullstart casing. Do I need that rod, or can I remove it as long as I seal the casing to the backplate??
 
you will save a lot of this PITA time by getting the Backplate......even if the leak isn't in the backplate it's a lot easier to seal and be done w/ it.....all the crap sitting in there for the pullstart is not really a good ideato leave in there.....
sometimes it sucks to see what you need and not want to spend the dough on it...let me ask you this....would the 26 bucks have been worth it if you were running these last 4 days instead of trying to rig up your existing backplate??
 
it happens.......use the RTV silicone sealant or some other high temp / gasket sealer and you should be good w/ your current stuff......
 
I'm not sure, or either I'm not following, why you are sealing the pullstart cord opening? I just converted a Hyper .21 8-port from a bump start to a pull start and I recall that there is a shaft that goes through the backplate that essentially connects the pull starter to the crankshaft. There's also a turbo fan looking deal that grabs the crank. What I do remember is that there is a gasket that goes on that starter shaft at the backplate opening, which may be your airleak. I then used RTV on the backplate, then screwed the starter on.

May want to see if you have that gasket and all the right parts. It's an odd set-up, compared to an OS mill or a HPI one. There's no traditional one-way bearing in there.
 

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