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Old 18-03-2023, 12:06   #1
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Prop Shaft In Neutral Only Spins Freely One Direction

Recently I’ve only been able to get 2000rpm max in forward gear. Neutral and Reverse work fine with full power. There is also a little bit of white smoke if I try to throttle past the 2000rpm max.

So after a new mixing elbow and a few other test, I tried to spin the prop shaft in neutral and it spins freely to the starboard side but not to the port side. The odd thing is when in gear, Forward is to Starboard and Reverse is to Port. The engine is 3gm30 with the vdrive KM3V transmission.

UPDATE: Upon further investigation, the spinning in both directions finds resistance. Some times it spins free and then it gets tighter and tighter and then it kind of breaks free and spins freely. Almost like screwing the top onto a jar and it slips past the tightest threads and has to be tightened again.

Are there any other test I can do to figure out more or just have a mechanic pull the transmission off. At one point I thought it could be from a worn cutless bearing does this behavior make sense? There is definitely some play at the prop end.

Thanks
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Old 20-03-2023, 06:36   #2
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Re: Prop Shaft In Neutral Only Spins Freely One Direction

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Originally Posted by theway View Post
Recently Iíve only been able to get 2000rpm max in forward gear. Neutral and Reverse work fine with full power. There is also a little bit of white smoke if I try to throttle past the 2000rpm max.

UPDATE: Upon further investigation, the spinning in both directions finds resistance.

Thanks
Look at the the prop, It may have a line or something wrapped up in it.
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Old 20-03-2023, 08:41   #3
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Re: Prop Shaft In Neutral Only Spins Freely One Direction

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Look at the the prop, It may have a line or something wrapped up in it.
Prop is clear, just checked. But for some reason it is spinning more freely today. Im gonna make a new post focusing on engine symptoms.
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Old 20-03-2023, 08:58   #4
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Re: Prop Shaft In Neutral Only Spins Freely One Direction

Fixed prop? In reverse if it's a fixed prop the load is less as the blade is not optimized for going in reverse. If you can't make as much RPM forward as reverse I'd look at engine filters or injectors first. Doubt it's a transmission issue.
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Old 20-03-2023, 10:40   #5
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Re: Prop Shaft In Neutral Only Spins Freely One Direction

Maybe a dry cutlass bearing and or stuffing box. These need water lubrication. Burp.
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