35 MPH 4200 RPM 99 SeaSwirl 175

basatum

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Jan 21, 2017
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I'm looking at buying a 1999 SeaSwirl 175 with a 3.0 Volvo Penta 135. I'm told it tops out at 35 MPH at 4200 RPM with one person in the boat. Original motor and outdrive. The prop is standard as far as I know. Does that performance sound about right or should I be concerned? It seems slower than other similar equipped boats.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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What pitch prop? Engine could be down on power (check the DIY stickies for low WOT) Should be able to rev to 4600 rpm and maybe about 40mph
 

dingbat

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Nov 20, 2001
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.....
While this model is also available in a slightly more expensive outboard version, the $35K price tag gets you a 'toey' 135hp 3lt Volvo Penta sterndrive that effortlessly propels the Seaswirl 175 I/O to 42mph at 4900rpm.

Guessing it's over proped
 

basatum

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Jan 21, 2017
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An over propped boat should go faster than stock all other things being equal, correct? So then if it's over propped and max speed 35 then there might really be a problem?

I'm planning on water testing the boat in April. Anything I should look for in particular? Can I trust the shop trying to sell it to do a compression test?
 

Scott Danforth

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NO. An overpropped boat only lugs the motor and ham-strings performance.
 
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