This was ODD

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Jeep

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Today , I fire up my buggy, it took several pulls as the owb is starting to slip a bit time to time when starting it cold.
It fired up and was running backwards!
Keep in mind, this is a Pull Start engine, hobao hyper mach .28.
I'm well aware that a 2 stroke engine of any fuel source can run backwards (as well as a 4 stroke deisel) and sound fairly normal if many conditions are right. As is the case with gasoline golf carts, (2 stroke engine) when you flip the reverse switch, you actually cause the starter to start in the opposite direction and the engine runs backwards.
But, how in the world could my RC engine have started backwards with a pull start?
Could it be that possibly with a VERY strange coincidence, that the last pull, I had almost reached a full compression stroke and it fired (slightly before TDC, as it shoud) and then pushed the crank assembly backwards just as I let tension off of the p/start and actually went through the next power stroke in the reverse direction?

That's the only explanation that I can come up with. A really odd coincidence of timing

It was a hell of a thing to see my buggy backing up at a high idle,,:OMG:


Jeep
 
Jeep, only thing I can suggest is.......

Ghostbusters.jpg
 
I've had it happen more than once. It happened twice on my Omega 21 Comp and twice that I can remember with an OS 21 RG in my savage. In both cases, the OWB was slipping pretty bad, so I think it "let" it run backwards.

It does sound really funny... not ha ha funny, but odd.
 
Jeep said:
Today , I fire up my buggy, it took several pulls as the owb is starting to slip a bit time to time when starting it cold.
It fired up and was running backwards!
A too-rich or over-primed condition on start up can cause this. What happens is it hydrolocks on you but the plug is hot enough to cause ignition under the compression and fires it back down the way it came, and as you know once it starts it keeps going that way . . .
 
And just to add, if it is running backwards, your one-way has GOT to be completely shot. Because if it were ok, it would have reeled in the pull cord, binded and stalled.
 
I would normally think exactly the same Candyman, but, I've started it several times since and it only slips a bit when cold starting, but after it's warmed up a bit, it doesn't slip at all.
Damned if I can figure how the owb isn't totally shot.

Jeep
 
Since I've had it happen more than once, I definitly believe you.

It might be kiind of like when guys use those roto-starts with a OWB that feels like it's gripping when they use their fingers to turn it. Then when the use the roto, it just slips.

Pull starts allow you to coax more life out of it. They let you "set" the bite, then tug. With a roto, it's either going to work or slip. No middle ground.
 
olds97_lss said:
Since I've had it happen more than once, I definitly believe you.

It might be kiind of like when guys use those roto-starts with a OWB that feels like it's gripping when they use their fingers to turn it. Then when the use the roto, it just slips.

Pull starts allow you to coax more life out of it. They let you "set" the bite, then tug. With a roto, it's either going to work or slip. No middle ground.


Yeah, I can see where a PS would coax a bit more life out of a owb, as teh PS buts more of a side torque on the input shaft and could cause the rollers to bite, where as a roto start applies more of an aligned torque and no "side-bite" to speak of.

I'm sure my OW is on it's way out,,but still functioning for now,,lol :)


Jeep
 

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