701 engine running backwards???

[Dski]

i just got back from riding the superjet i bought this winter.. its got a few problems.. One time it actually started and i realized it was sucking water into the pump cone and pushing it forward through the intake grate... its got TL and a lot of other mods to it.. does this sound like a timing/advance problem?? how can i deadvance. i took it out about 5 times and it only ran backwards once.. but it was some wierd ********!

 

[Matt_E]

Sounds like the timing is way off. You might need to figure out what the static and programmable timing is set to. You should be able to do this without taking the engine out. You need to take the flywheel cover off and go from there.
Download the MSD TL instructions from their website (www.msdpowersports.com) for timing.

 

[SJ/XPBri]

How did it start in reverse? I know that a 2 stroke can run "backwards", but can the bendix allow an engine to do it? Second, you can't even hook the polarity up backwards to get the starter to spin backwards. The ignition can allow an engine to run backwards, but what allowed it to rotate in reverse in the first place?
Bri

 

[Mile9c1]

The bendix won't start the engine if it gets turned backwards by the starter.

 

[SJ/XPBri]

The bendix won't start the engine if it gets turned backwards by the starter.

Yeah, I posted those 2 reasons in reverse order- brain fart

So my question is still, what started the engine in the reverse direction?

I'm not bustin' balls, just curious to see what could have caused it.
Bri

 

[Dski]

i have no clue what caused it.. ran it 3 times bfore that and things were spinning in the right direction.. started it up after lunch and it was sucking my bathing suit into the nozzle.. shut it off and restarted it and everything went back to normal...

 

[sflsurfrider]

once the engine is "moving", regardless of rotation, it wouldnt be that inconceivable to change direction, at a low and inconsistant rpm, if thats what the timing "wanted".

 

[MADMAT]

I have never heard of this before! What a trip!!

Maybe instant reverse is what someone needs to try a front flip:bigeyes:

 

[ski4]

last year at fsf paul was syaing the timing on his ski was soo advianced that at times it would run backwards too

 

[sflsurfrider]

upon starting, the timing should retard itself. if it doesnt, the combustion will happen when the piston is way btdc. this combustion (and lack of speed/momentum) could push the piston back DOWN before it reaches TDC, therefore spinning the engine in the opposite direction. i would imagine that bad things could happen like couplers loosening or impellers spinning off.

 

[ArtMaybee]

I've seen it happen on one of Paul's boats first hand at Lanier last year.
With total loss and a ton of advance they will definitely run backward.

I thought it was freaky until it was explained to me.

 

[Dski]

ok, well i was thinking of detuning it a little to run pump gas anyway.. if i change the domes so it runs at ~180psi. how many degrees of advance would be in the ballpark? what do you all run??

 

[nikad58]

the answer he is looking for "I think is" it will start backwards.. when you push the button and it cranks over if your timing is far enough advanced "sometimes" it will fire too early before the piston reaches TDC, it will push the piston back down, kick the bendix back in, and keep runing backwards.. the sad thing is it may sound funny but when you gas it..woooooo hooooo hang onto your love stuff.. its much more intresting to watch a dirt bike do it !!

 

[waxhead]

awesome
think of all the new tricks you can do with the ski
i reckon hook up would be an issue and the steering would be snatchy to say the least
but hey all in the advance of freestyle

 

[demolition_x]

the answer he is looking for "I think is" it will start backwards.. when you push the button and it cranks over if your timing is far enough advanced "sometimes" it will fire too early before the piston reaches TDC, it will push the piston back down, kick the bendix back in, and keep runing backwards.. the sad thing is it may sound funny but when you gas it..woooooo hooooo hang onto your love stuff.. its much more intresting to watch a dirt bike do it !!

that would be pretty interesting, never heard of that on an mx bike though, but that would be a great suprise.

 

[nikad58]

it used to happen on a dirt bikes at least once a weekend at bigger dessert races back in the early 70's.. dead engine start... kick, boom, everyone takes off and one guy heading backwards going over the bars into the next wave "the next line up" behind him..

 

[SUPERJET-113]

I have had that happen to me on a 2 stroke dirtbike.. CLimbing a hill and it bogged out near the top and and I rolled backwards a bit and it started up running backwards, I went down the hill backwards and and I wiped out again...lol COMBAT WOMBAT BABY!!! Hodaka style!
Fock that socked!