Probable wrong propeller on sea ray 195 with 4.3 mpi

bassjbl

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Jun 7, 2015
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hello I just purchased a 2007 sea ray 195 sport that has the 4.3 MPI mercruiser with an alpha 1 outdrive “can’t find the gear ratio”. When I was going through a more thorough inspection I noticed that the thrust washer was missing on the prop so I bought a new one and when putting it on I looked at the prop and it seems like the prev owner half assed replaces it “hence the missing washer”


the prop on it is a 13.5” 17p. That seems way too small for this setup. Or am I wrong? Thanks for the info!
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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gear ratio should be about 1.62:1 or 1.84:1

my guess a 15" 19p or larger
 

porscheguy

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Jan 17, 2013
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If a 1.62 then go with a 19p. If a 1.84 go with a 21p. Standard aluminum props in those pitches tend to be around 14-14.5” in diameter.
 

QBhoy

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Way too small no matter which of the ratios. It will not the limiter easily with that prop
unless you are at crazy altitude
 

bassjbl

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Jun 7, 2015
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So I went out with that prop, at max rpm “4800” I was going about 10mph. There was a lot of vibration. I ordered a quicksilver 21P 4 blade 8M0055536.
Does anyone think that there is more of an issue with this low of speed? Or was that prop that far off?
 

QBhoy

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Wow. Something is far wrong here. Even underpropped with a 17”. The boat should have rocketed up on plane and hit the limiter whilst still doing a fair speed. You wouldn’t even be on plane at 10 mph. Are you sure of this ?
 

bassjbl

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Jun 7, 2015
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Yes did not plane at all, speedo read 10 I did not do gps but it sure felt like 10 as well, I’m thinking that prop was heavily cavitating hopefully because my wake was huge, tried a few different trim positions to see if it would get better but it didnt
 

Bondo

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the prop on it is a 13.5” 17p. That seems way too small for this setup.

Ayuh,...... Sounds like a mid-size gear case outboard prop on a large gear case outdrive,.....

Is the barrel of the prop 'bout 4", rather than the 4.5" an outdrive runs,..??

That can be done, as the prop shafts are 'bout the same,.....

Yer results sure sounds like that's what happened,......
 

QBhoy

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Has the engine been out or replaced that you know of ? Maybe thinking it could be an issue with the coupler ?
 

bassjbl

Seaman Apprentice
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Jun 7, 2015
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All good, it was just the prop, don’t know if it was the size, pitch, or a hub issue but I’m glad it’s all it was! The old hub looked fine but it was a round rubber hub so tough to tell.
 
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