Need help picking a prop

[erikhill]

Recently found a 1976 Tri-Sonic with a 140 hp Mercruiser engine. I believe it has a type 1 outdirve. The boat has a dry weight of 2,300lbs. It will be used mostly for tubing, skiing, fishing, and drinking. I'm not real worried about zipping across the lake at a high rate of speed, but more concerned with pulling a 200lb guy out of the water to ski or wakeboard. This is my first boat and need to be pointed in the right direction. Any advice is greatly appreciated.

Thanks,
Erik

 

[Silvertip]

Re: Need help picking a prop

What prop does it have on it now? The diameter and pitch are usually stamped on the barrel of the prop between the blades or if you remove the nut, you might find it on the end of the hub. Look for 13 x 15 for example or a string of numbers that represent the manufacturers part number. Without and wide open throttle rpm and existing prop information we can't be of much help unless someone has the exact same boat/engine you do.

 

[erikhill]

Re: Need help picking a prop

Sorry, forgot to mention the boat did not have a prop on it when I purchased it. I was hoping someone might be able to suggest a prop from the combination of weight and engine size.

 

[ziggy]

Re: Need help picking a prop

i've got the same boat, but not the same engine. i was running a 17P w a 165hp engine..... it was too easy to reach wot. i didn't have the boat seviceable long enough to try different props. think i'd have gone to a 19P if i'd have got that far... with yer 140hp. i think i'd try the 17P for a starting point. then adj. from there for reaching the high side of your wot spec of 4200-4600 rpm........ i think i'd go for alum. too. the oring groove in the lower drive shaft worries me..... i'd rather break the prop. or at least hope it breaks instead of the drive shaft if i strike something.........