Why does my prop spin when still in Nuetral ?

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Big Pete

Petty Officer 2nd Class
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Aug 12, 2009
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Hi all

Just a small thing i have the drive in Neutral on the Mercury 80 outboard , with Mufflers on start the engine and it always makes the prop spin ?

Now surely in Neutral it should sit still . And when i spin it by hand prior to starting its all nice and spins albeit a little tight but spins .. so its definately in Neutral..

What worry`s me is when i eventualy get the Boat in the Water and start up, will i go racing off etc..

This is my first Boat so all new to this :)
 

Boss Hawg

Lieutenant
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Re: Why does my prop spin when still in Nuetral ?

Hi all

Just a small thing i have the drive in Neutral on the Mercury 80 outboard , with Mufflers on start the engine and it always makes the prop spin ?

Now surely in Neutral it should sit still . And when i spin it by hand prior to starting its all nice and spins albeit a little tight but spins .. so its definately in Neutral..

What worry`s me is when i eventualy get the Boat in the Water and start up, will i go racing off etc..
This is my first Boat so all new to this :)



Don't worry----It won't :D
 

Stachi

Lieutenant Commander
Joined
Jul 14, 2009
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1,671
Re: Why does my prop spin when still in Nuetral ?

this happens due to the driveshaft spinning inside of the lower unit and churning the lower unit oil
nothing to worry about.......tight lines bro !
 

Big Pete

Petty Officer 2nd Class
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Re: Why does my prop spin when still in Nuetral ?

this happens due to the driveshaft spinning inside of the lower unit and churning the lower unit oil
nothing to worry about.......tight lines bro !

Ok thanks but how did you know i intend to fish of it as well ? :)
 

freddyray21

Commander
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2,460
Re: Why does my prop spin when still in Nuetral ?

the little bit of movement you seen when running on the muffs in the drive will stop once the water surrounds the prop.
 

Silvertip

Supreme Mariner
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28,758
Re: Why does my prop spin when still in Nuetral ?

Look -- you said with the engine off and engine in neutral you can spin the prop by hand. That tells you the lower unit is indeed in neutral. If it wasn't you would not be able to turn the prop. Simply starting the engine doesn't change anything. Internal friction will cause the prop to turn but it will not push the boat when a load is applied (as in the water). Besides, the boat cannot go "racing off" as you put it because the engine is at idle. Trust us -- it won't run off.
 

coolguy147

Commander
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Re: Why does my prop spin when still in Nuetral ?

seem a little made silver tip?
 

Big Pete

Petty Officer 2nd Class
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Re: Why does my prop spin when still in Nuetral ?

Look -- you said with the engine off and engine in neutral you can spin the prop by hand. That tells you the lower unit is indeed in neutral. If it wasn't you would not be able to turn the prop. Simply starting the engine doesn't change anything. Internal friction will cause the prop to turn but it will not push the boat when a load is applied (as in the water). Besides, the boat cannot go "racing off" as you put it because the engine is at idle. Trust us -- it won't run off.

:eek: ok sorry .. i will trust you ..
 

Fisherball

Chief Petty Officer
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Mar 19, 2009
Messages
470
Re: Why does my prop spin when still in Nuetral ?

Hydraulic pressure. The oil is moving & any unrestricted part in there, your prop shaft, will also move. That's how an automatic transmission in a car works, specifically the torque converter. The torque converter has 2 blades that face each other with a heavy oil in between. One blade is connected to crankshaft, the other connected to the shaft that comes out of the tranny. When the engine spins the blade the oil spins causing the other blade to spin also. It has much more pressure than in your lower unit. On newer cars when the car reaches speed the blades are pushed together when the computer decides it's ok & they lock so there is no loss of power through the oil.
 

Big Pete

Petty Officer 2nd Class
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Re: Why does my prop spin when still in Nuetral ?

Thanks for that i have got the jist now,, so the thing will stop with the water resistance i presume ..

So i am not going to worry anymore , in fact i am not going to mention it ever again as long as i live ;)
 

Boss Hawg

Lieutenant
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Re: Why does my prop spin when still in Nuetral ?

Thanks for that i have got the jist now,, so the thing will stop with the water resistance i presume ..

So i am not going to worry anymore , in fact i am not going to mention it ever again as long as i live ;)

Promise? :p
You never know till you ask my freind :rolleyes:
Be safe & enjoy your new boat :cool:
 

Stachi

Lieutenant Commander
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Re: Why does my prop spin when still in Nuetral ?

we all have boats to fish for one 'species ' or another...tight lines ! ...lol
:D
 

King P.V.

Seaman
Joined
Aug 13, 2005
Messages
72
Re: Why does my prop spin when still in Nuetral ?

Rotational friction...Driveshaft is always turning, fwd and rev gears always turning, slight more tension of the prop shaft against the inner bushing of the fwd gear so it slightly turns as if in fwd gear...
 

itsaboattime

Senior Chief Petty Officer
Joined
Jul 4, 2007
Messages
791
Re: Why does my prop spin when still in Nuetral ?

Pete............the only dumb question is the one you don't ask. Believe me, when I first got on here I asked LOTs of questions. Some good, some not so good. It's all good.

A wise old man said "never procede in the face of uncertainty."

Asking is the best way to learn.

I do advise you to get a manufacturers service/repair manual. It is a wealth of knowledge.
 

Home Cookin'

Fleet Admiral
Joined
May 26, 2009
Messages
9,715
Re: Why does my prop spin when still in Nuetral ?

that little bit of prop spin in neutral is one reason to have the engine off when swimmers are near it--like picking up a skiier. B/c props get rough, they can nick a foot even when not turning under power.
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: Why does my prop spin when still in Nuetral ?

Actually some motors the prop will rotate very slowly even in the water.
but again it is simply the slight resistance of the prop shaft rotating inside the prop no more drive force that that you feel when you rotate the prop with your finger.
 

Knightgang

Lieutenant
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Oct 6, 2003
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1,428
Re: Why does my prop spin when still in Nuetral ?

So i am not going to worry anymore , in fact i am not going to mention it ever again as long as i live ;)

Okay, we will hold you to it... ;-)

we all have boats to fish for one 'species ' or another...tight lines ! ...lol
:D

Yep, but I know what species you were fishing for... sspp, (i will not tell though, you secret is safe with me....)
 

Kenneth b

Cadet
Joined
Oct 10, 2017
Messages
6
I understand that the prop will spin in neutral but if I try to spin prop by hand when the motor is off it will only spin in forward rotation.i have a 69 evinrude selectrea dose this motor have the neutral start safety and dose it only spin one way in neutral.
 

racerone

Supreme Mariner
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Dec 28, 2013
Messages
36,043
When that motor is NOT running it will be in FORWARD gear !-----Lower unit if in good condition kicks into nuetral after the starter turns the flywheel ONE TURN.
 
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