motor run off

[76delro]

1988 force 125 ran it today, motor kept running and it rev up...turn the key to off and pull key out did not stop.pull stop switch did not stop.had to cut fuel line to stop motor.
trouble shoot problem...still lost.
ignition wiring and color...S-yellow,C-green,B-red,M-white & a wire going to stop switch,I-empty,M-the one wire going to stop switch.
there is a blue wire not hook up.

terminal block reads
Y-starter
P-tach
W-magneto
G-choke
O-heat
R-bat.+
B-magneto
BLK-ground-

question??? is the stop switch supposed to be hook up on the 2 M's on the ignition switch.
how bout the blue wire thats hanging is that supposed to be hook up on one of the M on the ignition.
question??? how does a kill switch work.
thanks guys...

 

[JB]

Re: motor run off

Don't have an answer to your wiring question, Delro, but the runaway was probably a thermal runaway in which an engine is allowed to rev up with no load on it and goes into a Diesel-like cycle. Cutting off the ignition has no effect.

You are fortunate that your engine did not self destruct.

Never rev a 2 stroke over about 1500rpm with no load on it.

 

[Frank Acampora]

Re: motor run off

These engines need to have something done to turn them off. In your case, the CD boxes need to be shunted to ground. Should it happen again because of a broken wire, simply remove the hood and jump the white wires to blue on the terminal board at the starter.

Proper wiring is one white wire in the cable to one "M" terminal on the switch, the blue wire in the cable to the other "M" terminal on the switch.

Look closely at the engine terminal board. You will see that blue is jumped to ground.

SO the two white wires from the CD boxes connect to the white terminal, the white wire in the cable connects to the white terminal at the engine and the "M" terminal at the switch. The blue wire connects to the blue jumped terminal on the engine and the other "M" terminal on the ignition switch.

Incidentally, because these engines use a grounded overheat buzzer or light, it is possible to also jump the white to orange after disconnecting orange in the cable from the terminal board to prevent 12 volts from going into the grouning wire circuit of the CD boxes, thereby destroying them. It is for this reason that I have never done or recommended this modification. At any rate, if the engine overheats, the CD boxes would be grounded and the engine would shut down. Another major drawback would be that it would be impossible to start the engine until the engine cooled. Imagine what would happen if you were running an inlet when the engine stopped! Here is a case where safety takes precedence over possible engine damage. Again, I do not do or recommend this particular modification. Didn't notice I had the cursor in the wrong place. This paragraph should be last.

Turning the switch off connects the two "M" terminals and the CD boxes are grounded through blue, shutting down the engine.

The only difference would be if you have a dead man switch (kill switch) in the control box or on the dash. Then the white would go through it before going to the ignition switch. If the dead man was tripped, it would go to ground no matter what position the ignition switch was in, thus the engine would not start or run.

 

[eurolarva]

Re: motor run off

Another way to kill it is to choke it. If automatic choke dont work plug the air flow on the carbs.

 

[76delro]

Re: motor run off

thank you guys for all the replys i end finding the problem.source was the ignition it's faulty, so i ended buying new ignition and went ahead and install a new stop switch also.i hook up the stop switch on the two M's on the ignition. thanks again guys.

next project is to replace the impellar. im pretty sure will be asking some question for that also.
also been reading the post on how to replace the impellar i think 5 times already...wish me luck.

by the way happy holidays.