Motor Tuning Problem - Almost dies after WOT

[iDrift10]

Well before the colder weather my Revo was running perfect. However, now that the temp has dropped 30 degrees I'm having a little issue. I know that when the temp drops you should richen the HSN because of the denser air. My Revo was running a little warm (280-300) so I richened the HSN to get the temps down. Now that the temps are in a respectable range I'm having a issue after wide open throttle. From take off all the way through the power band the engine runs perfect; nice trail of smoke, nice performance, nice temps. However as soon as I let off the gas after a high speed run the car drops to a idle that is barely running then after a few seconds or if I tap the gas the idle returns to a perfectly fine healthy idle. If I lean the HSN back up to get rid of the almost dying issue the car over heats. Ran a few tanks trying to trouble shoot it and I just can't figure it out. Thanks in advance for any help.

Side Note: Running a Picco 26 Red Dot.

 

[lesclaypool]

Make sure your idle gap is set for about .5-1MM max. Then be sure your linkages are set so the idle gap doesn't change when you hit the brakes. Then check that it goes WOT as well. After all that is set up slam the air filter on and tune that thing like a champ. I suspect you need tweaking on the LSN and or idle screw. Refer to this tuning guide here: https://www.rcnitrotalk.com/forum/showthread.php?t=76808 . Follow that directly to tune that thing like a hero and get all the chicks looking your way.

 

[iDrift10]

Idle gap and LSN needle are working like a charm. Idles beautifully, has perfect accel and smoke after idling. It's just the weather cooled down so I had to richen up the HSN needle a bit because it was getting to hot. If I lean out the HSN the problem goes away but it runs to hot. If I richen it it almost dies after WOT but runs normal temps.

 

[lesclaypool]

Have you checked for air leaks?? Whats the temp outside when you're running?

 

[iDrift10]

Yea I was looking all over for air leaks last night couldn't find a thing. Temp is probably low to mid 60s.

 

[lesclaypool]

You're certain the idle gap isn't so big that the LSN is pig rich to compensate?

 

[JoeMAXX]

Watch this hope it helps. I have always been anal and sealed my new engines before I have run them for the first time after my first air leak. New fuel lines help also. Over time the fuel line from the tank to the engine will loosen up and should be replaced. If long enough you can just cut a 1/4 inch of the lines leading to each connection. This will cure most air leaks

[https://www.youtube.com/watch?v=tZ3WcPoa1DY&feature=relmfu

 

[iDrift10]

Yup sure the idle gap isn't to big, it's very very very small.

I've watched all of Squirrels videos in his how to tune series hoping to find a solution but no dice Joe

 

[lesclaypool]

Follow the tuning guide regarding the LSN. Once you're warmed up good do so WOT passes and then temp the engine. Does the temp drop rapidly? If so you're too rich on the LSN. Does the temp sit there or even climb?? Then you're too lean on the LSN. If you see it drop a degree or so every 5-6 seconds, you'll be spot on. Don't bother with the pinch test, there's too many variables.

What fuel and plug are you running?

---------- Post added at 9:51 AM ---------- Previous post was at 9:48 AM ----------

Forgot to add - what about binding?? Everything move easily in the drivetain? Gear mesh on the spur and bell isn't too tight? No bad bearings?

 

[iDrift10]

Well I think I got it working today. I recently tore it apart and rebuilt the carb. Today I went out and it was having the same problem. Even though the idle was perfect, and there was sufficient smoke at low throttle I was able to richen the LSN about 1 turn, engine never stalled, idle remained same.. weird I know. This got rid of the near dying after WOT. Thanks for all the tips, tricks, and suggestions everyone!

 

[lesclaypool]

Awesome! Post up a vid!

 

[iDrift10]

Copy that, I'll try to get one next time I drive it.