tuning problem

[t-maxxracer32]

hey i have a picco .26 in my revo and i cant get it tuned right... it starts up instantly (has roto start) but then once i get it going it just dies after like 30 seconds...



too lean? too rich?



if you need any more info lmk!

thank!

[glassdoctor]

Do you have it just at idle for 30 seconds or does it run ok and rev up??

Does it only die when it comes back to idle?

It may be tough to guess what is wrong if it won't run for more than 30 sec... my nitro *cough* takes that long just to warm up and start running ok. Really it takes a couple laps opn the track before it's acting ok.

After it starts, get it revving good... with brief full throttle stabs... keep doing that for a minute to get the temps up and keep it running. If it won't do this then I'm not sure where to start.... other than to go back to factory spec needle positions.

[t-maxxracer32]

ya thats kind of the problem... not really sure where to start. i think i just need to run it and get it warm before i start driving around for fun

The picco 26 is a good engine, but can be a bear to tune. Does yours have the mid speed needle? If it does, did you mess with it? Never touch the mid speed needle.

Anyway, it's hard to tell without being able to hear the engine run. If you had it tuned and it just started doing this, it may just be a temp change that's doing it. It is getting warmer and may be running fat on the top and bottom.

I like to run my engines a bit fat on the bottom. I tune my engines so that they will only idle for 5 seconds or so before they start to load up. If I let one of mine idle for 30 seconds, it would probably kill when I got on the gas.

Without being able to hear/see the engine run, the only adivse that I can give is to go back to the stock needle settings and tune from there. I don't want to be presumptuous, but when you tune, leave the bottom needle alone until you have the top tuned. The bottom really only affects right when you get off of the line anyway (unless it's super fat). When you tune the top, don't just run it up and down the street and start turning the top end screw. Run it for a few minutes and listen to it. Get it to where it's running the best, then back off on the screw about 1/16 to 1/8 of a turn, to take it a bit easier on the engine. Better yet, don't push the engine. Just tune it to a satisfactory level of performance. As long as it doesn't sound like it's choking on fuel or gasping for fuel, and you see a thin trail of smoke, you are good. Once you have the top set, tune the bottom. If the engine seems like it's just running too good, you're probably too lean. LOL

[t-maxxracer32]

lol well its just for a freind. i have to get it running before he will buy it. so i just need to it to stay running for more than 30 seconds lol.

thanks for your advice!

[The*rc*dude]

i had the same prob with my TRX2.5 and i was too rich. does it idle for a little wile and cut off when u punch it? if so your too rich based on my experiance.

[The*rc*dude]

oh yea thare was one winter that i had to run my engine at more than half throttle for a little wile to warm the engine up and then it'd run fine.

[squeeforever]

It might also need a rebuild. As soon as it heads up, it will lose compresion if thats the case. See if it has good pinch, if not, chances are it needs a rebuild and thats your problem.

[t-maxxracer32]

what do you mean by good pinch?

and ya it does what you said rcdude

[squeeforever]

Compression...Roll over the crankshaft by hand. It shouldn't be easy at all...If it is, you will probably need a rebuild.

[t-maxxracer32]

oo kk ill check that!

thanks!

[neweuser]

I would personally richen the low needle and check the pinch as squee said. If it's cold, and needs a rebuild, most likely it would run till it got hot at least then kill.
You can check the compression fairly easy though.

Another reason might be air lek. How long has it sat for?