Throttle Stick

mtk1977

Member
I’ve heard horror stories about open 2 cycles running away. Seals going bad, carb throttle getting stuck etc. Has anyone experienced this on the track and found a good way to shut it down before damage occurs and or wrecking? Do’s and do nots?
 
That’ll always be a no for me when it comes to two strokes. Having to hold the throttle wide open to get an alky smoker to start while not in the kart spells disaster 😬
Not because I know anything about them, I didn't think it was a good idea when I saw them start to try it, but by the time I spoke up they didn't hear me and it was to late
 
I’ve heard horror stories about open 2 cycles running away. Seals going bad, carb throttle getting stuck etc. Has anyone experienced this on the track and found a good way to shut it down before damage occurs and or wrecking? Do’s and do nots?
I ran my water pump backwards on my 250 and i guess piston got red and the motor kept running away from me.it wound up melting piston😂
 
Only a couple things you can do .
Ground the coil with a switch .
Reach over and close throttle .
Choke the air filter
Jerk the plug wire
Mash the brake
Don't panic .
 
Best way to stop a runaway 2cycle is to take away the fuel or air ,I personally always carry a sandwich bag in my pocket. A little tough while driving but better than a catastrophic consequence. Chuck.
 
Honestly anything can stick open, go thru your equipment and make sure everything is functioning properly on the carb and throttle return spring on the kart...then take steps like everyone else is saying.
 
Prc chassis have there throttle spring return bolted to the floor pan, not a really good design when the floor pan flexes it will pull the throttle open on yea. Found that out on the kart stand.
 
First instinct should be to slam the brakes, this gives you time. If you can't choke it then open the needles until it quits.
 
Prc chassis have there throttle spring return bolted to the floor pan, not a really good design when the floor pan flexes it will pull the throttle open on yea. Found that out on the kart stand.

I had a PRC and the first thing I noticed was the cheesy throttle assembly and their very flexible floor pans.
 
I remember one street race during a local festival back in Spain during our ICA DD days. Pits were on a small street by the main one where the race was, and when I tried to push start mine it took off on its own. We needed to jack a car to get the kart from from under that car. It was a mess. And I wasn't the only one who suffered that during those days, believe me.
 
I run a thick foam filter that I can reach over and choke the carb. It's happened a few times over the years and it worked everytime.
Yes, on DD when you push start them if the only thing you can do if check the cable and eveything like the arm often, but when you push start them once they stick open before you even jump into your seat there is no way you can reach the filter or even anything you set to cut the ignition.
 
You gotta be faster getting in.
Well if set correctly and nothing fails it won't take off on its own and the only issue is if you are not fast enough it dies or won't start. Now if it somethings messes up and it starts and takes off fast you'd better not try getting i the kart.
 
If it's a high horsepower motor like a UAS I'd put a kill switch on and good brakes

I’ve considered installing a kill switch, but I’ve been told numerous times that it won’t stop a pegged motor from dieseling with motoplat/selettra/PVL or I’ve been told it will fry the ignition just like pulling the spark plug boot. Some people say it’s fine, most don’t and I’ve been looking for a straight answer on that for awhile now. I’ve got big brakes and a LF Hegar brake too, which makes me feel safer if things go wrong
 
a ignition kill will not shut off a runaway 2 cycle.. the motor will act like a model glow engine.. have had this happen twice on dyne, once on track.. I used a nos solenoid fuel shutoff, with Lipo battery.. on dyno, I didn't use filter and kept a plastic bag in my pocket... if you blow out a seal, bag doesn't work so well.. fuel shutoff, takes a few seconds to fuel lock...
 
Very few things will stop even a "small" 100cc direct drive. Like i said a car might be one of them...
 
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