Switching from 3 to 4 blade

Palivec108

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Apr 8, 2017
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I have a 1984 sea ray Monaco 187 it has the mercuriser 228 (gm 305) I believe the prop is 14 1/2 x 19 aluminum 3 blade I hit a high spot at my local lake and it's done enough damage to replace it I want to switch to 4 blade prop but in sure on what size to get to balance out would 14x19 work? Thanks in advance
 

walleyehed

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What model of alum 3-bld were you running? Do you want to try SS or stay with alum? Great advantages with SS..

And welcome aboard!
 
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Palivec108

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I would go with SS if the Price is right The 3 blade prop is the original the numbers stamped on it are 48-832830
 

walleyehed

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Ok, if going to 4-bld, it would be nice to know what your rpm was with the original prop. Speculating, I have a 19ft Wellcraft with the same powerplant. I use a 19P SS but I'm also 3600ft above sea level. This runs about 5200 WOT, but hole-shot is really good.
If you can confirm rpm at wot we could make a better guess. If the 19 you had was near the top of your rpm range, an 18P 4-bld would likely give better hole-shot, better mid-range but may lose a couple mph on top.
 

Palivec108

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Okay well wot she ran right at 5,000rpm at about 45mph now the prop was already dinged up pretty good dinged up pretty good and paint was worn, but after I caught a high spot in the water and mangled it it was only wanting to do 35 - 40 mph at 5,000rpms
 

walleyehed

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5000 is good, I prop for hole-shot so I'm running a bit higher rpm than recommended. If paint was worn, T.E. cup probably is too. I really think a Solas Rubex in 19P (3-bld) will be OK in alum. with the rubex you can replace just housing if you tear a blade off. 18P in 4-bld alum and a high quality SS would likely be in a 17P.
I'll go get a link and post to what I believe would work.

4-bld alum option: http://boatpropellers.iboats.com/Mer...t_id=983708892
4-bld SS option:
http://boatpropellers.iboats.com/Mer...t_id=983708892
 
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Palivec108

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Okay sweet I was really looking into a prop by turning pony there hustler model but it only comes 14.5x17 or 14.5x19 would useing the 17 over rev to much and would I lose a lot of speed or should I go with 19 and take the rpm loss?
 

walleyehed

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Long-term better to lose a little speed and keep the engine happy, so 17P is better than lugging but TP hustler is a different design than stock and historically, the TP pulls harder so may not lose much...???
 

Palivec108

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Okay well I greatly appreciate all the information and help you have gave me I went ahead and bought tithe TP hustler 14.5x17p 4 blade with a new hub kit only cost $88 so if I would have to change to another prop this really isn't that big of a loss but we will see how it performs again thank you very much this site is awesome
 

walleyehed

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Post back with your results when you get to run the new prop. We all learn from the feedback. :)
 

Palivec108

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Well I got to take the boat out yesterday with the new prop. I think I made the right choice Now I'm running about 47 48 mph at 5100 rpm's with The trim set at the sweet spot , Bo got on the plane a lot faster and was able to stay up plane at a slower speed we had the boat out for about four 4 1/2 hours after a while of running it out wide-open throttle we slowed it down and I let my buddy drive at a slower speed and and after about 2530 minutes of him going about 25 or less the boat started to hesitate and then just stalled almost seem like it was out of gas it would not start for 25 minutes so we got pulled back to the dock I got home and threw some muffs on it and threw a splash of gas in it not her couple crancks started right up I think I experienced the gas turning into Vapor from heat inside of the engine compartment
 

82rude

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May 8, 2012
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If that happens again look to the anti siphon valve.Over time they can get sticky or just plain fail and cause those types of issues.
 

82rude

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normally in the tank.It prevents fuel from siphoning back into the tank thus leaving you with no gas up at the motor.
 
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Palivec108

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Okay so the problem came out to be when I installed the sending unit I didn't adjust the float length right and it was telling me I had just under a half tank when really it was empty haha my fault thanks for the tips and advice tho
 

walleyehed

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You should also have a vent blower installed...When running slower speeds in hotter weather, use it.
 
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