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Aug 19, 2010, 01:31 PM
"Chuck Yeager"
hotdog1's Avatar
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Help!

evolution .46 tunning question


ok so i just bought a used funtana from craigslist and it has a evolution .46 with a 12x6 prop i got the motor to idle fine and transition to wot fine and when i do the pinch test at idle it raises rpm's slightly then dies but when i do the pinch test at WOT the engine immediately dies so that means it is too lean right? so i turn the high speed needle out counter clockwise to richen it but even at 4 turns from closed it still dies immediately when pinched at WOT other than the pinch test it seem to be fine but this worries me does anybody have any ideas ?

THANKS
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Aug 19, 2010, 02:16 PM
Registered User
Sounds like the high speed needle is lean and maybe trash in the spraybar. Have you removed the needle and blown through the tube?

howell
Aug 19, 2010, 02:46 PM
"Chuck Yeager"
hotdog1's Avatar
Thread OP
no ! how do i go about doing that ? just unscrew the needle till it comes put ?
Aug 19, 2010, 03:12 PM
"Chuck Yeager"
hotdog1's Avatar
Thread OP
ok just removed both fuel lines from the high speed needle assembly and unscrewed the needle valve and removed it. blew air through it and then flushed it with fuel. still no difference i can turn the needle valve eight turns out and it make no difference.
Aug 19, 2010, 04:31 PM
Three green
The pinch test is done very fast at full throttle. If you pinch and release about as fast as you can say "pinch and release" and you get an increase you are looking good. at full throttle if you pinch and hold and you get a short increase in RPM followed by a flame out, you are in the sweet spot.
Aug 20, 2010, 02:30 PM
"Chuck Yeager"
hotdog1's Avatar
Thread OP
just a split second pinch and it dies. One of my other engines is an evolution .60nx and i can pinch it for at least a 1.5 seconds at WOT and the rpm's raise before it dies. but this one i pinch it and i can't let go fast enough before it dies i think there is deffinitly something wrong
Aug 20, 2010, 06:19 PM
Three green
I would say then that you must have a fuel blockage. If you can open the high end valve and this does'nt change there must be a blockage or no pressure to the tank or carb problem or something like that. If you remove the line at the carb and blow in the pressure line from the muffler do you get full flow fuel out the carb line? You will need fuel in the tank and the HSN out about 5 turns. If so, and you have muffler pressure to the tank, then I'd say the problem is at the carb. Good luck. Keep trying. Just chase the problem down until it's tired and kill it.
Aug 20, 2010, 08:01 PM
"Chuck Yeager"
hotdog1's Avatar
Thread OP
did what you said and it was hard blowing into the pressure line but fuel did come out of the carb line but im not sure what kind of flow is "normal"
Aug 20, 2010, 08:31 PM
Registered User
The first thing to do is remove the remote high speed needle and mount it directly on the carb. I had a evo 46 that had to always be tuned, then I mounted the needle on the card and its one of the best running motors I have. I even think it has a little more power than my O.S 46 ax.
Aug 20, 2010, 09:59 PM
Airplane Gearhead
You might also try a smaller prop...a 12x6 is too big for a .46
Too much prop load will effect the tune...try an APC 12x4 and see if that helps.
Last edited by proptop; Aug 21, 2010 at 08:23 AM.
Aug 21, 2010, 08:04 PM
Registered User
I agree a 12 x 6 is little too big for most .46 size engines.

I run an APC 10 x 6 on My SportJett .46 ( but it's designed to turn 16,500 rpms.)
My other .46 engines like the APC 11 x 5 or the 12 x 4 props.
15% nitro.
Good luck, hope this helps the problem.
Jeff
Aug 21, 2010, 09:49 PM
registered user
My Evo .46 runs very well with a a Zinger 10x5 wood, 15% nitro, and a FOX idle long idle bar plug. It really revs up with that prop. Plenty of thrust for my SPAD 3D. I'll have to try pinching it at WOT and see if it acts like yours.
Aug 22, 2010, 03:09 PM
Three green
If you had the needle valve opened up at least 5 turns and it was hard to get fuel to come out when blowing in the muffler line, then thats a problem. If you blow hard you should have fuel flowing freely out the carb line. remove the needle valve unit from the engine and unscrew the valve right out. Flush the housing out onto a paper towel with alchol or fuel or something , and see what was in there. Wipe of the needle and re-install but put a little fuel on the needle's O-ring so it slides in without cutting the O-ring. Hope you find something. Good luck.
Aug 22, 2010, 07:40 PM
Registered User
I had an Evo .46 and never got it to run correctly... the needle valve seemed to have little if any affect at all. Mine would not maintain full throttle for any significant period of time. I sent it back, they returned it after "fixing" it, but it still did the exact same thing. I bought an O.S. 46AX and have never had any problems with it. I know of others who have had issues with the Evo .46... I also know some who love it - almost seems like some are good and some are bad - not sure. Anyways, just wanted you to know that you're not alone with your Evo .46 troubles.
Aug 22, 2010, 07:50 PM
"Chuck Yeager"
hotdog1's Avatar
Thread OP
ok switched out the 12x6 for a 10x5.5 and replaced the fuel tanks and all lines but then it started to rain GGRRRRRR!!!!! so tommorow i will test it


WELL that did the trick thanks everyone !!!
Last edited by hotdog1; Aug 28, 2010 at 12:00 PM.


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