Losing 30% of top speed, same RPM, why?
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Losing 30% of top speed, same RPM, why?
Hi guys, ive run out of places to ask, so here is my last shot. Sorry its not a performance boat, but like i said...i have no idea whats going on here. My girlfriend has a 210 searay bowrider, with a 5.0 EFI, alpha drive, and its bone stock from the factory. Early last year it ran a consistent 45 mph on the speedo i had not driven it. (according to boat test it should run about 49). motor says optimal RMP range is 4400-4800 on the arrestor. Ok, so im driving this thing and it feels like we are pulling an anchor! its running 32 mph @ 3900 rpm's (i verified on my phone GPS) and then i start trimming it up bit by bit...it hits 34, then dips to 32 back up to 34, down to 32 again, i did this over and over, and then i hit about 4800 RPM and we are struggling to hold 30 MPH...any ideas here? boat sits a bit, and might have slight algae on the bottom, but i cant see that accounting for 12-15 mph. nothing changes year to year, same prop, body of water, etc...im gonna pull it out this week and have a look, any idea what i should look for or do? Boat gets out of the hole fine, and planes out fine, its just painfully inefficient running WOT.
If it matters i have a 232 baja, and fully trimmed out its a handful, this thing trimmed out feels like the tabs are all the way down, only problem is, boat doesnt have tabs.
thanks everyone!
If it matters i have a 232 baja, and fully trimmed out its a handful, this thing trimmed out feels like the tabs are all the way down, only problem is, boat doesnt have tabs.
thanks everyone!
#3
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Since you are running on the Chain O Lakes, I would check your prop and also pull the boat and spray the hull with a mix of Sno-Bol and water to kill the slime growth. 2 weeks in the water and you will have fuzz growing on the hull that will rob you of at least 5 mph.
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#6
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Could be a hundred things but given that your presumably turning the same RPMs as always the most obvious culprits are likely crud on the hull bottom, a failing coupler or prop hub, or a banged up prop.
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thanks guys, ive been able to check the prop edges while in the water at the sandbar, and they all seem ok, much better than the prop on my boat. i know there wasnt anything in or around the prop or drive as well. Guess i should pull the prop off and check the hub and go from there...im thinking a failing coupler would cause me to run 5 mph and not 30. Ill also give the bottom a scrub this weekend and see what happens.
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Pull it and power wash the bottom.