On a 2 stroke it's not all that hard to get one to run backwards given the right conditions, but a 4 stroke motor is a bit more difficult. Not that it's impossible on a 4 stroke, just not as easy (as evidenced by the several stories here of motors running backwards). Those old Husky bikes were notorious for starting with the motor running backwards!
And FWIW fellas, almost every 2 stroke snowmobile sold today has a button on the handlebars that stops the motor just before TDC then fires off the spark plug to start the motor in reverse and allow you to back up.

 

Hey. I've got an old wife. And I still sometimes catch myself looking for something to set a battery on so it's not on concrete. Sometimes it's hard to overcome old habits we were taught when we were young.


I don't like 3208's. My first experience with one threw a push rod that twisted around the cam and ruined the block. On a used truck with impeccable maintenance records, that we had had for 5 weeks. Talk about a quick way to add 10k to the price of a vehicle.

Interesting. I've never been on a snowmobile, so I'd have to take your word for it. I think snowmobiles require snow, which requires cold. Seeing's how I'm not a fan of the last two items, I probably won't be on one in the future either.

 

All it needs to do is reverse the polarity of the starter ....

 

i know for a fact that if you spray ether in the air box while trying to start, it will make a big fireball, blow out the top of the air box, and it will burn until you put it out with an old ripped up pair of sleep pants soaked in coolant that i had laying around...

 

Details are needed ...If the engine was turning over at the time , what you posted is not possible...

 

one person sprays, one person cranks, air box goes boom. very possible. i have the cracked air box, toasty air filter, and soiled panties to prove it. you can try if you like but i wouldn't recommend it!

 

If the engine is turning over , it cannot happen .. I have done it .. no soiled anything ...Try again , your s would be the only engine on the the planet that would not have the valves closed during combustion ....

 

i'll post a pic of the can and the air box tomorrow...
i wish i had video, that would have been great for youtube

 

When I was about 12 years old, my Dad's Rototiller wouldn't start for me. Dad had a small bottle of ether with a screw cap. I pulled the spark plug and poured some either in the cylinder. I only meant to put one drop in but I got too much. I replaced the plug, wrapped the starter rope and pulled it. I got a big blowie explosion and the engine rattled to a stop. It had no compression. When I pulled the rope again the engine just rattled and spun.
Well, I never told Dad what happened. He took it to get fixed and the repair guy said he didn't know how it could have ever run as the piston was too small!!!

 

What if the glow plug is hot enough to ignite the ether without the assistance of the heat from compression?

 

Pre-Ignition of the either.

Though it would technically blow out though the valve. The chances of it actually damaging the connecting rod is slim to none.

I'd worry about ether pre-det damaging valves or pushrods.

 

But Rick said that's not possible if sprayed while the engine is cranking.

To be clear, I'm talking about the scenario that dave22r is describing above.

 

I know you are.

A flash back is completely possible if you ask me.

it just depends on how hard the engine is sucking the either and how much you are spraying.

If you get a pre-detonation while the motor is turning, its going to flash back out the valve. If it's fire coming back out and your still spraying the either, you will have the situation as stated.

I think this is one of the reasons why a lot of people suggest not spraying either.

Moderation is different to everyone.

What I'm saying is that if there is fuel in the intake, the fire is going to burn back out the intake faster than the motor will suck it in.

 

I would never mess with Ether.

 

Dave raises a very good point (from experience) that the hot glowplugs could cause a backfire of ether. like Tayln says, if the cylinder isn't sucking hard enough and you're still spraying ether, the frame front on the ether vapor can travel back out of the intake cylinder through the air filter, back to the can of ether in your hand/PJs. come to think of it, even if the engine is sucking hard, i can't imagine the velocity of intake air being greater than the flame front speed of combustion.

however - i go back to the advice of the powerstroke tech i talked with about a year ago. his method of using ether (he lived in Wisconsin and said he had many mornings where it was necessary) was to turn the key to on, wait until the wait to start light goes out, pop the hood, get your ether can, wait 5 mins, spray it on the filter, then hop in the truck and turn it to start directly from 'on' and you're fine. this method makes sense as the GPs have cooled and only compression heat (when the intake valves are necessarily closed) can ignite the ether. ...or if you have GP disable switch installed, you can just disable them by switch and save yourself the 5 mins.

i also have to chime in that just last week, i finally got fed up with the dying battery/generator/voltage regulator/something else on my 1980 yanmar diesel tractor and gave it a shot of ether before starting. it has no glowplugs, and i barely sprayed any ether at all, but that sucker started up like it was a 100 degree summer day. through the first half of the winter, i'd been hooking up the one half-good old battery out of my powerstroke that i'd keep trickle charged through the week. the ether can is much less hassle than a 30 lb battery and fumbling with jumper cables all the time. plus, the starter cranked for 1 second instead of 30! i'll let you all know if my tractor becomes 'addicted.'