• Welcome to RCTalk! 🚀

    Join the #1 RC community where hobbyists connect, share, and get expert advice on RC cars, trucks, boats, drones, and more!

    • ✓ Friendly & passionate RC enthusiasts
    • ✓ RC tips & troubleshooting
    • ✓ Buy, sell & trade RC gear
    • ✓ Share builds & upgrades

Revo Tuning Issues

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
C

chuckjones

RC Newbie
Messages
7
Reaction score
0
Points
0
RC Driving Style
Hey there -

I've been running my revo for a couple of weeks now, a full gallon of nitro (20% traxxas stuff). Full stock so far, except for a glow plug igniter instead of the EZ Start glow plug line that gets in the way.

I've had some serious issues with the way it's been running.

I'm not very good with the tweaking of the HSV and the LSV yet - I have a post-it note with what richen and lean direction is, >3 seconds lean the LSV, etc. But I think my issue may not be related to tuning.

When I started it up - fired right up as usual. It had a nice low idle, no movement, blue smoke coming out. I give it gas, it moves - but very slowly. you can hear the RPM's of the engine, but it's not moving fast, not shifting gear either.

So I tweaked the LSV and the HSV - for two hours. At one point I must have went too lean, because it stalled, and smoke came out the pipe - assume that's not good :) It started up again, and I cranked it rich 1/4 turn.

Same response. Sounds great, but no movement. Barely makes it up a hill. You can hear it's full throttle, but it's not translating to the truck. I made it super rich, to the point it would stall when I gave it any throttle, and then leaned up gradually. No difference.

Does this sound like something else? Clutch slipping, or....

BTW - what is the "default" turn settings for the HSV, LSV, and the idle? I want to reset it, but don't know what they are...

Thanks!
 
Sounds like your slipper is too loose. It's on the spur gear, use an 8mm wrench on the nut in the middle while holding the spur to tighten it. (righty tighty lefty loosey)
 
Is your throttle servo opening the carb all the way? It's a frequent problem on revos that are still stock. The heave throttle return spring on a lot of them is too strong for the servo and keeps the throttle from being opened all the way.
 
olds97_lss said:
Is your throttle servo opening the carb all the way? It's a frequent problem on revos that are still stock. The heave throttle return spring on a lot of them is too strong for the servo and keeps the throttle from being opened all the way.
Click to expand...

that spring all out sucks, if you run it ditch it and use a few small, super small rubber bands
 
It does sound like the slipper clutch now that I read more about it, will test that out. Would a crash cause that to loosen? Just for my info, can someone tell me how to reset the LSN other than "flush" (sorry I don't understand).

It's definitely opening up to full throttle. No doubt about it. That's what is so perplexing, it sounds great, and I felt like I had the right mixture going, just not spinning the wheels.
 
Last edited:
Ok, I went out, it was a bitch to start. It turned over, after draining my ezstart battery and my glow plug igniter battery. I was trying to see if it was the slipper clutch, when it stalled. And won't start at all.

This is what the manual says about setting the LSV:

"Notice the thin darker gray area between the low speed needle and the throttle arm. This is actually the other end of the slide valve from inside the carburetor. The low-speed needle is threaded into the slide valve and is set flush (even) with the edge of the slide valve."

Makes no sense at all. The screw turns more than 360 degrees.... it turns at least 5 turns. So what the F does flush with the edge of the side valve mean, is this during the 2nd turn, the first turn, or the "nth" turn of the screw from closed???? GRRRRRRRRRR
 
olds97_lss said:
It means you put the screw flush with the housing that surrounds it. That's the baseline.
Click to expand...

Ok, do I close it all the way first, and then back off to the point where it's flush with the housing? Or do I turn it out X turns first, then make it flush?

Wait. By flush, you guys are saying the head of the screw is flush with the housing? I was thinking the "slit" was parallel to some piece of the body... but is what you're saying, tighten it all the way, and then back off of it, so that screw head is flush with the surface around it?

Sorry for being lost, but I've got so many issues now, I'd pay for someone to just hand it to me tuned at this point. I'm not sure about any setting, except for the high speed valve.

The tightening of the slipper seemed to work. It was more responsive. When it stalled though, when I tryed to start it, the wheels were grabbing when the ez start was turning. So i think that mean I had to back off and loosen it again. The flywheel now turns freely when pushing the EZ start.
 
You don't need to tighten it all the way, just set it so the head of the screw is flush with the housing around the screw head.

Notice how the flat top of the LSN screw is flush with the housing on this carb?

axig0020.webp


That's what you want to do with yours and that's what I mean by flush.
 
Last edited:
LOL.

Thank you!

I got it.

I finally got it running again. It was extremely rich. Couldn't start it because of that. Once I got it a little leaner - by making it flush, it was still pretty rich, but I was ok with that. I ran a couple of tanks to shake off some of the dust and get back to normal.

I was then able to play with the slipper clutch a bit. At first it was about 1/2 throttle before it caught the wheels, and then a little tighter and it was quicker on the trigger. Back to normal. I wasn't able to open it up enough to see if would shift into 2nd gear again, but that's ok for now.

I have 2 other random questions. The wheels get loose all the time, is it ok to put loctite on the thread to stop that? I'd assume so?

And also, around the glow plug, there is dirt that I just can't get out of there. I'm afraid to remove the glow plug to put in after-run oil, because of the dirt getting in there. It's not a ton of dirt, but still. With the nitro in there, it's too sticky.

Thanks again!
 
question 1 yes its ok to use loctite to keep your wheels tightened
question 2 u can do it one of two ways that i think of, either blow it out with air can or get a quetip and wipe around the glowplug before takin out
 
I find that loctite gel or stick works much better for courser threads like wheel nuts than the liquid stuff.

I do both of what X posted around the GP prior to taking them out at the end of the day.
 
Awesome, thanks guys, just took the whole thing apart to clean it up, ordered some broken parts that I found, new wheels too. Stoked, now that I learned so much with your help.
 

RC Builds

Back
Top