Prop spinning backwards

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CypressHunter
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Prop spinning backwards

Post by CypressHunter »

What causes that on shut down?
13' 6'' Cotton Mouth 220 GPU 70'' signature series

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CJB0470
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Re: Prop spinning backwards

Post by CJB0470 »

I have a stock 220 with a 500 Holley, single mag. If I run pump gas it raises the head temp and if I do not let it idle to cool it will diesel like you are talking about. Av gas solves the problem for me, 100ll it's the lead that keeps the head temp down. Regardless of what I'm running in the tank I always let it idle for a while before I shut it off.
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southbound125
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Re: Prop spinning backwards

Post by southbound125 »

never seen them run backwards but if you run a hot plug or have a lot of carbon built up in the heads the fuel will ignite because carbon and or plugs are red hot and will give a ignition source. in my day we called that dieseling. we had all kinds of tricks to get carbon out like pouring water or trans fluid down the carb while reaving your engine. it never seemed to work though but we had a good time!
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swampsquatch09
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Re: Prop spinning backwards

Post by swampsquatch09 »

Mine does it if i shut down hot, just idol around a bit before you shut it off thats how I keep mine from spinning backwards at shutdown, i run pump gas 93 havnt ran enough avgas to notice anything
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Bruce
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Re: Prop spinning backwards

Post by Bruce »

if its a gpu like your signature suggests and you have an electric fuel pump just shut it off and let it run out of fuel gives it time to cool down and wont diesel now if you have a manual pump let it idle a couple minutes which you should always do anyways then bring it up to 12-1400 rpm cut the mag and push the throttle to the floor may not be the right way but it wont run backwards like that
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dusty burch
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Re: Prop spinning backwards

Post by dusty burch »

If u put av gas in it it will shut off properly

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TheElevatorGuy
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Re: Prop spinning backwards

Post by TheElevatorGuy »

I don't know why or how but my 220 luckily never does that......I have seen others do it.......and I have always ran 93 in it because the previous owner did too....... :scratch:

I try to let it idle and cool off before shutdown but not always and even in an immediate shutdown it does not do it!!!

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Stewie
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Re: Prop spinning backwards

Post by Stewie »

I always let it idle for a min then just pull my lean rich cable All the way up to lean and it shuts off easily. :old_glory: :rebel: :florida: I have also seen the 220 zenith carbs with the fuel shutoff solenoids does the same thing no diseling.
Last edited by Stewie on Fri Oct 11, 2013 9:06 am, edited 1 time in total.

SkinnerBack
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Re: Prop spinning backwards

Post by SkinnerBack »

Or shut it off by pulling the lean out all the way up if you have one.......

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swampsquatch09
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Re: Prop spinning backwards

Post by swampsquatch09 »

hogdogs2009 wrote:I always let it idle for a min then just pull my lean rich cable All the way up to lean and it shuts off easily. :old_glory: :rebel: :florida: I have also seen the 220 zenith carbs with the fuel shutoff solenoids does the same thing no diseling.
How do you have your lean rich cable set up? is it similar to the way a throttle is set up with a cable or rod?
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mcm4
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Re: Prop spinning backwards

Post by mcm4 »

I had the same problem with my bbc....

I solved it by putting an idle solonoid on the carb, when I flip the switch the idle drops down to about 300 and as it is doing that I can turn off the ignition with no dieseling....

pretty simple and cheap setup

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Re: Prop spinning backwards

Post by cummins diesel power »

mine diesels when I stop sometimes, but if I just let it idle for a little bit
before I shut it off it wont diesel
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In the Glades
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Re: Prop spinning backwards

Post by In the Glades »

Need to let it cool off or lean it out til it turns off.
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Stewie
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Re: Prop spinning backwards

Post by Stewie »

swampsquatch09 wrote:
hogdogs2009 wrote:I always let it idle for a min then just pull my lean rich cable All the way up to lean and it shuts off easily. :old_glory: :rebel: :florida: I have also seen the 220 zenith carbs with the fuel shutoff solenoids does the same thing no diseling.
How do you have your lean rich cable set up? is it similar to the way a throttle is set up with a cable or rod?
I used a small $30.00 pto cable and just made a bracket to hold the cable in the position to work my lean and rich very easy to do push and pull! :old_glory: :rebel: :florida:

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John Fenner
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Re: Prop spinning backwards

Post by John Fenner »

Idle setting may be too high and too rich, adjust it down to about 400 RPM then carefully with a stubby screwdriver turn in the idle mixture screw (top rear center of carb) till it begins to stumble and cut off, then back it out till it idles smoothest. It might have 10:1 pistons and too hot of a plug, a bit more information like this could steer us to a better cause.
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