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Mercury Prop?

M

minytrker

New member
I have a 23P Mercury Marine prop right now. My boat takes off and runs good. Is that a good prop? At 60mph Im at 5k rpm. Being a 84 with unknown hours how many rpm would you turn? I currently go across the lake at 4k rpm all day and never burn oil or have problems.
 
I need to know the exact prop it is and your horsepower. i have an exciter with a 150 horse and turn 5500 rpm with a 21 pitch stainless prop, 5600 rpm is about all you want to go.
 
All I know about the prop is it says mercury marine 23P and is a 5 blade. I have a 265hp mercruiser 350. How long can I hold it at 5600rpm?
 
I'd make sure it had forged pistons, rods, crank, and 4 bolt main first- before I ran it ALL day that high on an I/O. Ask me how I know......lol!
 
Im pretty sure the motor is all original, so its 25 yrs old with unknown hours. I got a steal of a deal on the boat and just want to enjoy it without putting money into. Right now I turn 5,000rpm for very short periods of time and 4,000rpm for long periods. Being the boat is so old I do alot of preventative maintence. I grease the boat every trip to the lake and check all the fluids. I change the oil as soon as its started to look dark. I installed new plugs and wires, and changed the fuel filter. Top speed isnt a priorty, but if I can safely run 5,000rpm all day vs 4,000rpm then I would but its not a big deal.
 
minytrker said:
All I know about the prop is it says mercury marine 23P and is a 5 blade. I have a 265hp mercruiser 350. How long can I hold it at 5600rpm?
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until it pops! seriously, under a heavly load that's a bit high for a stock 350 marine engine. also, it is a good bit above the peak hp for that engine. If it is stock you'll go a good bit faster woith a higher pitch prop... but probably worth checking your tack first if you can hit 5600 with a 23" prop...

even with forged pistons, crank, etc... i woudn't run that way for very long without a good oil cooler...
 
minytrker said:
Im pretty sure the motor is all original, so its 25 yrs old with unknown hours. I got a steal of a deal on the boat and just want to enjoy it without putting money into. Right now I turn 5,000rpm for very short periods of time and 4,000rpm for long periods. Being the boat is so old I do alot of preventative maintence. I grease the boat every trip to the lake and check all the fluids. I change the oil as soon as its started to look dark. I installed new plugs and wires, and changed the fuel filter. Top speed isnt a priorty, but if I can safely run 5,000rpm all day vs 4,000rpm then I would but its not a big deal.
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you can run a good bit 4800 or so (I believe the factory redline for that engine), and if it's got good compression, holds oil pressure and doesn;t rattle, run it like you stole it.
 
Most 350 I/O's were in the 4200-4600 and some were 4800max. Are you sure your tachometer is correct and not reading high??
 
PA-21 Skater said:
Most 350 I/O's were in the 4200-4600 and some were 4800max. Are you sure your tachometer is correct and not reading high??
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Yeah pretty sure its an aftermarket tach. I have no reason not to believe it, it doesnt sling or anything and doesnt bounce around. The prevous owner had the redlined marked at 5k so that is what I have been using. Like I said I have been running it for 15-20mins striaght at 4k and doing this everythime I go out. I also take it 5k for maybe 1-2min each time I go out. The other day after the hydrofoil instlation I hit 5500rpm twice by accident. The boat is still making power at 5k but I am concerned spinning it that being possibly 25yrs old.
 
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