motor just revved up on its own???

[copster]

hello a,, i need help with something. i was working on my 50hp evinrude spl 2cyl and adjusting the air fuel mixture screws when the motor just took off. the motor revved up to about 10,000 rpms and would not shut off. i turned the key of and nothing. then i pulled the fuel of the motor and nothing. i checked the flappers in the carbs and they were closed. it finally shut off when it ran out of fuel.

the timing bolt and nut under the flywheel was loose prior to all of this so i adjusted it slightly to tighten the bolt. if anyone has any suggestions why it did this it would be great. thanks in advance. i thought it was going to start throwing parts through the motor.

 

[PS94]

Re: motor just revved up on its own???

It leaned out. was this from you messing with the screws? who knows. Is there a vacuum leak?
got hot and ran away. The engine was hot enough to continue detonating the fuel without the aid of spark..
Or your key shut off does nothing...check for spark with key on and off..

 

[BonairII]

Re: motor just revved up on its own???

Being a newbie...I always have an emergency shut down plan in my head when I'm test starting/running my motors and have the cowling off(so I can yank plug wires if necessary) I also have a fire extinguisher at hand, too.
Never had it happen, but I'm always worried that the motor will "runaway" and I won't be able to shut it down. I HAVE had a car motor runaway, though. and had to stall it by putting it in 5th gear and dumping the clutch.

 

[boobie]

Re: motor just revved up on its own???

If it ever does it again, stuff a rag or two into the air intakes of the carbs. This will happen to a mtr if you're running it at to high a rpm on muffs with no load on it.

 

[copster]

Re: motor just revved up on its own???

Ps94 I think you are right. It got real hot real quick. I think the timing may have gotten messed up... Bonaire I like your thinking about a fire extinguisher with you. I thought I was going to need a new motor...lol. Boobie I think I am going to do that when I start it again. I did not think of that. It would stop the air from entering the carbs. I just don't want this to happen to anyone. If it would have thrown a rod or the flywheel with me next to it, it could have been bad. Or deadly .

 

[BonairII]

Re: motor just revved up on its own???

I like the "rag in the carb" idea also. Obviously, the cowling and/or air silencer etc need to be off for this to work.