High idle Revo 3.3

[Jeremy]

i can't get my revo to idle down. i bought the truck used and it runs good, just dont idle down like it should. it idles just at the point of moving. i have adjusted the idle screw and no luck. i have reset the hsn and lsp to factory but it still idles high.

 

[nitrojedi]

how big is the idle gap ? chances are your issue is with the linkage or the gap..

 

[chaos2767]

Check the throttle return spring that is attached to the throttle linkage.

 

[Jeremy]

My carb closes like it should. Is it possible that suckung air somewhere would cause it?

 

[wwit]

Sort of late to the party. But its not uncommon for air leaks to happen on older nitro RC's. Usual cause comes from the carb/engine flange. Either whatever seal's it has gone bad, or could be just a loose tension screw. It doesn't take much air to weep between them and cause it to lean out and rev.

 

[Sekan Tunon]

Here is a little back story.
I put this engine in maybe three years ago. Ran 1/4 gallon thr ough it before I ran another half gallon of a special break-in blend my LHS perscribed. The enging over heated to the point of melting 3 pull starts. Before i shut it down. When I started the engine up last month. I had to replace the slipper clutch, glow plug, and spur gear. I am running 33% in it now. And have been through 1/2 gallon of that so far. I running 16t clutch bell. And have used a 38t 40t and now a 36t spur. I can not remember which gear set i have installed. I have the center diff. And CV drive train.

I still can not get a good launch or great speed from this thing. My 3.3 honestly gave me more. I am afraid to lean out either needle too much as i learned they were lean from the begining and thats why it overheated before. I am getting lots of blue smoke. So i think i can lean out more. As it seems to be a bit too much smoke. I am ready to throw this thing out. ANY HELP WOULD BE GREATLY APPRICIATED. PLEASE HELP!

Since this video has been shot it will shift consistently, it hasn’t melted anything, however I still get sluggish acceleration and a very low top end. Though it does swell the tires. This engine still has it, I know, I just can’t get it. I get lots of blue smoke, and drips of oil from exhaust and behind the fly wheel, no more than usual. I believe I’m still running rich, but I am afraid to lean it out too much more. I have been tuning from low speed needle to high speed needle. Nothing I do to the low speed needle seems to be helping acceleration. All I really notice from the high speed needle is shifting, no real get up and go at the low end or serious speed. Pictures of the needle settings are provided.

 

[Sekan Tunon]

I did have to replace the spur gear after that. I believe i just had it set to tight as on installation it passed the paper test.

 

[ninnon]

First of all, 33% is WAY to high, that is probably why everything is overheating, you only use 25%+ during a race environment. Secondly, that air filter is not helping at all, nitro engines are very sensitive to things like that. The way you've got it further forward isn't helping, and neither is the fact that your running one of those real engine breathers as a filter, they are no good in Nitro RC's, they do not work. You also need to give that thing a good clean, shorten fuel pipes so that you don't end up with unnecessary resistance, check your fuel system for air leaks and then check your running the right type of glow plug. Then you can start turning. First, get your remote and centre all your trims, then, set your idle screw so that it is flush with it's housing, then take off your throttle servo horn, recentre it and set your idle gap using the screw on the carb body, you should have a 1-2mm gap. Then, do the same for the steering while you are at it. After you've done that set your high speed and low speed needles flush again, get some 20-25% fuel, and follow this tuning guide here:
https://www.rcnitrotalk.com/forum/threads/nitro-tuning-tips-and-tuning-flow-chart.60832/
Also read this:
https://www.rcnitrotalk.com/forum/threads/nitro-rc-beginners-guide.68224/
Hope it helps

 

[Rolex]

Absolutely you MUST ditch that air filter. Get a 2 stage foam filter.
How it launches from a dead stop is all in the LSN. Adjusting it will also require an idle adjustment. Make small adjustments when the engine is up to proper temp, and run it around without going to WOT to see if it changed before adjusting it more. When you keep going too far in one shot, you'll never get it right. Once your idle is good and your launch is quick, only then do you start adjusting the HSN for WOT runs.
Every time you run you'll probably have to make a HSN adjustment for ambient temp and humidity, but the LSN can remain the same.
Get a temperature gauge. Leaning the LSN for proper launch can overheat the engine if you go TOO lean. Check it regularly while tuning.