--Has anyone had their 2-Stokes "Runaway/diesel"???

[TatTooL23]

wondering if anyone has had their 2-strokes run with kill switch off, key off, and no plug wire on? like it starts up then goes crazy and you try all of those mentioned things to kill it and it doesnt work. the engine gets hot enough where it will combust gas and air with no throttle and no spark. its a real scary thing when it first happens. let me know if this has happened and what was the cause. thanks guys....

[fabiodriven]

It's usually a lean condition but I think timing can have something to do with as well, don't quote me on that though. You're getting it so hot in the combustion chamber that something is igniting the fuel mixture other than the spark plug. I have also heard of a piston or head with gouges from a previous failure adding to the problem. The sharp points heat up easily and cause pre-ignition. More than likely you are running out of fuel somehow.

[bcredneck]

john deer sleds will idle for about 2 min if you get the motor hot and pull the plug wires but the motor had preignition problems

[pablo]

I've had that happen to my first 85R. It turned out to have an intake air leak.

The rubber intake boot was very hard and difficult to install the carb. So I replaced it and no more air leak.

[hillbilly 200x]

I have had 4-stroke lawn mower engines do that where I work, lol kindy fun the only way we got it to stop was to take the spark plug out

[Bryan Raffa]

Happend to my 490 running Alcohol.. the best way to stop it,,, and the only way.. is to GIVE IT WIDE OPEN THROTTLE!

[fabiodriven]

the best way to stop it,,, and the only way.. is to GIVE IT WIDE OPEN THROTTLE!

I didn't know that. That's some good info right there.

[TatTooL23]

yeah it was crazy! i thought it was going to explode. ill try filling the gas tank, and checking the intake boots. was just so nuts to pull the spark plug wire off and have it revving wide open still.

[bkm]

Happend to my 490 running Alcohol.. the best way to stop it,,, and the only way.. is to GIVE IT WIDE OPEN THROTTLE!

I was just going to say the same thing. I had a Kawasaki 650 stand up jet ski that would do that if you started it out of the water. Hold the throttle wide open and it would die. Kinda goes against all rational thought but it works.

[ezmoney1979]

I was just going to say the same thing. I had a Kawasaki 650 stand up jet ski that would do that if you started it out of the water. Hold the throttle wide open and it would die. Kinda goes against all rational thought but it works.

I also had it happen while working on a friends JS550 in his garage. As it began running away I instinctively pulled the coils wires but to no avail. I didnt know the full throttle trick at the time so I just threw a rag into the intake.......... which just angered the twin cylinder even more:lol:

[bcredneck]

trowing a rag in there just gave it more gas

[Aka_am]

This is true adding rag; equals more fuel. open area; equals lean condition and it'll die.

I rode a minibike around for a month by using a rag instead of a carb. Not a very good idea. I caught it on fire actually, but it still ran. I never did find a carb, so I upgraded.

[SWIGIN]

I always called this ''death rev'' since thats what it sounds like it's going to do to your motor....kill it...lol

[corndawg]

I rode a minibike around for a month by using a rag instead of a carb. Not a very good idea. I caught it on fire actually, but it still ran. I never did find a carb, so I upgraded.

o really??:lol: ....i used a soup can for a piston in my bike :rolleyes:

[NINJA]

Yes this happened to my R at the last Imperial Invasion. I had run out of fuel with the petcock on primary on my ST tank. I hit the killer, but to no avail, I then flipped the petcock to reserve, she mellowed down after that. What sucks though is I'm down to 175 psi on compression after that incident. Time to re-ring it.

[plastikosmd]

This is an issue with a rollover of a diesel tractor. Cutting the fuel or giving it 'gas' doesn't do a thing as the tractor starts consuming crankcase oil. It is quite scary esp after just surviving a rollover. I have seen many suggestions and access is limited due the rollover, usually. Some have tried to stuff a rag in the open exhaust, no easy task with a hot pipe at WOT. Another suggestion is to give it a blast of CO2 from a handy extinguisher. Often getting it directly into the intake is a challenge with the hood down on a tractor that is on it side or worse. Some machines (or can be added) an emergency air intake shut-off. These are operated by a variety of methods (http://www.amot.com/Z_Dead%20Datasheets/4261.asp). Decompression will also help. See wiki here
http://en.wikipedia.org/wiki/Diesel_engine_runaway
not sure about the suggestion of the high gear plus all breaks engaged, if you arent in a complete panic by then it may work

[devilman]

i had this happen on an 85R i had while i was messing around the yard. i am thankful for the direct tv dish pole that stopped me. It revved high and took off, so i pulled the clutch in but my fence/garage caught the lever and broke it, turned kill switch off but that didn't shut her down and the front brake wouldn't hold the power she was giving. couple feet to the left and i probably would have ended up in the windshield of my truck and dead. very strange sequence of events.

[swampthang]

My 85 tri-z went crazy when the port on the side of the cylinder fell off that goes to the fuel pump. Only way I got it shut down was to shift up to 5th and dump the clutch. Scary stuff hearing it turn such high rpms after a fresh 80 overbore.

[TatTooL23]

this happened on my quadzilla. hopefully its just a fuel issue or something simple. we will c this weekend.

to stop it i ended up holding the brakes and the machine and put it in gear. again that was after kill switch, key, gas line, and plug wire did nothing. i also will be compression testing it now.

[brd812]

Check your air screw on the carb, it heppened to me once, during a race I lost the air screw and when I came into the pits and hit the kill switch it wouldn't die and it reved and i dumped it in gear and she siezed. look you bike over real good . Quadzilla oh the memories, I couldn't keep a head gasket on mine for the life me. Good luck

[tri-Z ripper]

Happened to me twice on my old RM 250. once tried dumping the clutch and holding brake! but it dumped and spun throught the brakes good clutch and proceeded to kick rocks knocking out my basement window it died shortly after. Second time was the day before a hill climb. i was practicing some hill climbs dumping it in 3rd and ripping up a sand hill. well my idle screw backed out and sucked some sand into the throttle body holding the throttle wide open 3rd gear power band up a hill. there's a pic some where of me nose diving trying to get away from it at the top of the hill! That was scary as :trailpro:
http://i66.photobucket.com/albums/h265/german0024/DSC02475.jpg