• 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

sticky carb slider on 4.6?

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
1

1500valk

RCTalk Addict
Messages
580
Reaction score
0
Points
96
RC Driving Style
Just got my Savage 4.6 out to do the break in, but I did have to lean the HSN out almost an entire turn before it would even get close to 200 degrees, but still plenty of smoke.
but anyway, that isn't the problem.
After about 1 tank, I noticed my carb slider was not returning to the idle position (engine off). The carb return spring was still there, but the carb slide required a push to return to idle. Then after a couple movements of the slide with the linkage off, it started to stick worse. I put the linkage back on and the servo almost couldn't pull it open. Anyone else have this problem?
I imagine I will have to contact HPI to get a new carb. If the carb can't return to idle, there is a very good chance of a major runaway.
 
You're right there. A stuck carb=runaway. You may want to take a minute to spritz a bit of denatured alcohol or nitro wash in the slide to see if that helps. If not, then I'd call HPI.
 
That might be right on. Because I noticed it was sticking worse when the engine was not running. But.... when there was fuel going through it, it worked pretty smooth. Also, I am going to increase my return spring tension (i have done this on previous cars and the servo is fine with it), to ensure that the carb ALWAYS returns.
Tannera, I checked it with and without the linkage attached, so that part is cool.
 
Last edited:
take the slide out of the carb and polish it w/ a dremel....then check your linkage like mentioned before....it should be as straight as possible.....if not it can wear a spot in the carb body and make it stick there more.....
 
Ok, you mean polish with a dremel buffer and rubbing compound?
 
Yep.....take out any imperfections on the metal to metal...also check your rubber boot for tears....I had an OS carb get trashed cause I didn't see dirt was getting in the boot......
 
Well, i checked it again, and now it's moving fine. I wonder if it has to do with the metal slider and composite carb body expanding at different rates when hot?
 
Also check the tip of your idol screw . Sometimes when people are braking in a new engine the will crank idol screw in to keep it running so take it out then see if it still hangs up
 
another thing is to check the linkage screw that holds the linkage and the servo thottle. that screw that holds the L shape piece and makes it swivel may be a bit to tight. if it is to tight it will cause binding. someone on here added a bearing to make it smoother. if that isn't the problem and its a little loose as it should be pull the throttle body out, clean it, and spray it down with some WD-40 and slide it back in a wet. should smooth the throttle action quite a bit. i had to do all the above mentioned.

thinking of running truggy style today at the track temps are back to 72 degrees here in so cal.
 
well, the problem disappeared. I will run it later this week and see if it crops up again.
 
The problem came back again. I took the entire throttle slider out of the carb body, and removed the LSN so if I polish it, it doesn't get any crap in it.
Anyway, I noticed no imperfections of the carb slider. Should I still polish it?
The linkages are all free and clear, with a straight shot to the carb.
I am concered because the carb stuck a little when running it. It stuck enough that it would not let the servo apply full brakes. I am doing the "ofna" linkage mod, though, so my carb response will be a lot more positive.
 

RC Builds

Back
Top