Making a saw run backwards ?

[junkman]

Anyone tried it yet ?

 

[jmssaws]

Anyone tried it yet ?

Not intentionally.

 

[sweepleader]

Mercury outboards used to run backwards, no gears, had to stop the motor for neutral, safe for skiers climbing aboard, you knew the prop was not turning cuz the engine was off. Carbs were constant vacuum, no normal throttles. "Throttle" lever at the driver's seat just advanced the timing till wide open then jammed the carbs open too. Starter ran both ways depending on "throttle" lever position.

If a guy had a chainsaw that would run backwards it could use those chains they have in commercials with the cutters facing the other way, eh?

 

[isaaccarlson]

Some of the old tractors would run backwards. I remember lugging it down and then switching it off until it almost died and then turning it back on again and going backwards.
I am sure a saw would run backwards just fine, but your oil tank would get pressurized and maybe blow a gasket. Even if you only ran it for a short time, you may end up with a nice mess when you open the oil cap.

 

[sawmikaze]

Try klamsoil.

 

[Duane(Pa)]

You should have seen my buddy's Hole Shot when his 1972 Carabella motorcycle was running backwards..... Some early Deere diesels would do it too. Speeds were a little more "manageable" on the tractors....

 

[jakethesnake]

Harley Davidson golf cart two stroke runs forward and backwards I studied one my uncle has it it still runs but that's how it's Spose to work

 

[RIDE-RED 350r]

Rotax Electronic Reverse found on 2-stroke powered Ski-Doo snowmobiles starting in around 2002. Push the "reverse" button, the engine almost shuts off, but then re-fires itself running backwards. Apply some throttle and you are backing up. Be careful with the throttle because there is no rev limiter in reverse and the sled could technically go as fast in reverse as it can in forward. All they had to do was use a secondary clutch with a 2-way helix that would function in both directions of rotation....

Yes, 2-strokes can run in reverse pretty easily.

And on the oil pump running backward theory: Looking at how the oil pump works, I don't think it cares what direction it is spun, at least on my 300 series XP saws anyway. And second, if it did in fact reverse and pump backwards all you would do is pump air into the tank, and if your oil tank vent is working, no pressure would build.

The bigger issue for me would be how to keep the clutch on the crankshaft!

 

[Simondo]

Anyone tried it yet ?

What do you have in mind ?

 

[sefh3]

If you advance the timing enough it might do it.

 

[cobey]

If you advance the timing enough it might do it.

I had one with too much timing
Pop and run backwards sometimes

 

[huskihl]

Most saws run about 25 to 30° timing advance. That's Before TDC. If you got it to 25-30° After TDC, in theory it would run the same backwards, other than the coil advancing its own timing with higher rpm. The crank throws might disrupt flow, might not, idk.

 

[Crzybowhntr]

Anyone tried it yet ?

Maybe put gas in the oil tank??

 

[VinceGU05]

just flip the recoil spring and wind the rope on the opposite way and done. dont know if the oil pump will work in reverse thou.

 

[Chainganger]

I ran 049 glow plug engines on little airplanes when I was a kid, they often went backwards

 

[TJ the Chainsaw Mechanic]

Turn the chain around and put a gear on.....that'll do it.

 

[Jughead]

yeap heard many old motocross racers say that they got one hell of a suprise.lol

 

[Al Smith]

More than likely you would spin the clutch off given enough time .

Ha the old 71 series GMC diesels would start up backwards then promptly suck all the lube oil out the blower intake in short order .

 

[wcorey]

Some coils won't trigger running backwards.
And wouldn't the timing be way retarded, like firing 25-30 degrees atc...?

 

[DSS]

Wtf do you want a saw to run backwards for?