Prop slippage

Capt. Hoss · **Posted:** Wed Sep 05, 2012 9:24 pm

OK I know it is not a Four Winns, but this should apply to any boat. My F-I-L has an 18 foot Mariah Shabah with the 3.0 4 cyl. in it. I think it has a 14.5inx19p prop. When he gets to about 13-14 mph(gps)it seems to start slipping. It still pulls up on plane but it(at WOT)just slips. Itdoes go away with some speed but, hewould like to get it fixed so it pulls allthe way to the top speed. He is unable to go to a bigger diameter of the prop just not enogh room, so we are thinking about a pitch changefrom 19 to a 21. Any advice would be great.

ric · **Posted:** Wed Sep 05, 2012 9:42 pm

Capt. Hoss wrote:

OK I know it is not a Four Winns, but this should apply to any boat. My F-I-L has an 18 foot Mariah Shabah with the 3.0 4 cyl. in it. I think it has a 14.5inx19p prop. When he gets to about 13-14 mph(gps)it seems to start slipping. It still pulls up on plane but it(at WOT)just slips. Itdoes go away with some speed but, hewould like to get it fixed so it pulls allthe way to the top speed. He is unable to go to a bigger diameter of the prop just not enogh room, so we are thinking about a pitch changefrom 19 to a 21. Any advice would be great.

Depends on the ratio, but I put a 21x14.5 on my 3.0 H180. No real gains, but it was a crappy solas prop. Move to a VP stainless or a Laser SS (if MC) you will feel a difference.

Walt · **Posted:** Thu Sep 06, 2012 5:18 am

That almost sounds like the hub is slipping, and not so much cavitation.

Capt. Hoss · **Posted:** Thu Sep 06, 2012 9:57 am

I thought it was the hub spinning but we pulled the prop off and it shows no signs if it spinning. And as much as it is doing it I would think that is would 1 show it and 2 getting worse.

RotaryRacer · **Posted:** Thu Sep 06, 2012 9:59 am

It could be the coupler on the back of the engine also...

Cap'n Morgan · **Posted:** Thu Sep 06, 2012 10:01 am

It does sound like a spun hub to me. Or possible too much trim causing cavitation. Hopefully not the drive coupler....... :cry:

ric · **Posted:** Thu Sep 06, 2012 10:19 am

What MPH is he getting at WOT? (GPS)

Capt. Hoss · **Posted:** Wed Mar 27, 2013 12:52 pm

OK so I have an update to this very old thread. We were in the garage working on my F-I-L boat, normal spring things, as I was looking at the drive I noticed that the prop had some "play" in it from the shaft. Front to back. So I started looking and it looks like someone pulled the spacer off and didn't replace it, so this caused the prop to grind off part of the case off and cause the prop to cavitate from the exhuast going out between the prop and the case. So it looks like he is going to need a new lower case. Which I have found are expencive.

neutron · **Posted:** Thu Mar 28, 2013 6:45 am

that deffinitly could be a problem, you would think you could feel that kind of vibration?

Capt. Hoss · **Posted:** Thu Mar 28, 2013 7:39 am

No vibes, nothing. It definatly was a head scratcher. But now that we have it figured out. Hopfully this will get fixed and he can be back on the water with it.

www.iFourWinns.com

Prop slippage

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