v spec that is a pain

[mfroot]

Ok the engine is a friends that is new to the nitro so I have been trying to help him with it. The engine was run-in per the os book and ran good during run-in and for about three to four tanks after that now it's a pain in the a$*. The engine started idling high and all over the place so we tried to tune to no avail. I have read a lot of threads on the v specs and we have tried everything. These are the things I have done.
sealed back plate
sealed carb
replaced front bearing
changed glow plugs (3 different ones) all osp3
Now anything above half throttle kills the engine. I have worked it into very lean and out to very rich, still having the same problem. One thing I did notice is it will rev to 3/4 throttle instead of half with the glow plug warmer on. Any help would be greatly appreciated because he is getting frustrated with the hobby and I enjoy having someone to race with even though his losi is no match for my kyosho. :blbl:

[z3usX5]

Most likely its your tune. If it is idling high richen your bottom and lean your top end so the 1/2 throttle does not kill the engine.

[mfroot]

Most likely its your tune. If it is idling high richen your bottom and lean your top end so the 1/2 throttle does not kill the engine.
We have went both ways rich and lean an hour at a time its like its not responding to the adj.

[scoobie]

measure the idle gap

[mfroot]

measure the idle gap
ok when you say idle gap that is the space at the end of the slide what should it be thanks scoobie

[Dave D]

Check the head bolts, make sure that they are not loose becouse it could be sucking air in that way also.:shoot:

[LUV DA AIR]

P3 plugs are long turbo plugs right? sorry I run O'donnell and RB plugs and not familiar with OS stuff.

Running a short plug, in a turbo button will do this. Seen it just last week aint that right cbonner?


measure the idle gapwhat he said^^^^^^^^^^^^

ok when you say idle gap that is the space at the end of the slide what should it be thanks scoobieWith the slide at closed position use a 1.5 - 2 mm allen like a feeler guage. This will get you close, be careful anymore than this and your idle speed will be above the range of adjustment for the bottom end needle to have any effect. If it is, the bottom end will not tune right, no matter what you do.

If none of this works, I would pull the all the needles, inspect the orings for damage, re install to factory setting and start over again.


maybe rogma will jump in here. He knows OS very well and gets 10 min. run times from VSpecs.

[scoobie]

P3 plug is Ultra Hot, and the correct plug to use. One thing Im wondering about though, is what % of nitro does your buddy use, and what deck height is he running? If he added the extra shim, he should pull it out so there is only the one thick shim (silver) and one thin (copper). That should be good for 20 or 30%

Remove the carb insert and set the idle gap to .5mm. Set the low speed needle flush with the body, then set the mid needle to flush, with the top groove of the screw pointing at the 2 o'clock position. For the HSN go three turns out from closed.

That should put you in a good spot to retune from. The only needle you wont need to touch is the mid. Let us know how it works out

[spanky]

Could be sucking air somewhere. check the carb to see if its tight. u might want to try a little rtv silicone around the carb and back plate. just thought I would try to help. I know how it can be.:cussing:

[scoobie]

...dont go too crazy with the torquing on the pinch bolt. The plastic sleeve on the vspec carb doesnt like to be overtightened. If you go too tight, good luck getting the carb out of the case. You want to go just a little past snug...

inspect the carb boot. The blue ones are kinda thin, and can be torn pretty easy. Best replaced with the black VG/XZ/Speed boot

[iLL-Mitch]

I know you've already said its the correct glow plug but thats what it sounds like to mean... ive seen it in my buddys 10th scale... exactly to a T of your problems.. double check the plug and put a brand new one in... be sure you are using a p3....

[mfroot]

Not sure but i think we found the problem and that is the tank have not tested it yet but will let everyone know.