97 Bayliner Capri 1700 with 120HP Force original prop?

[gmstreetmaster]

Hello, I just purchased a 97 Bayliner Capri 1700 with 120HP Force. The motor has been replaced and has a low hour motor on it. The boat fueled up with about 4 people will do 35ish (@5000 RPM) after adjusting the trim. The prop on the motor doesn't have any markings or numbers to determine the pitch and size. The boat has plenty of power and gets out on plane really fast right now. I would like to step up the pitch to get 40- 42 MPH out of it. I mostly use the boat for cruising and sandbar hopping so no need to have a ton of power for pulling (also I could always swap props if I did).

Any suggestions on what prop pitch would be on there currently? Not sure what the stock pitch is, what pitch is recommended to get me where I'd like to be?

Thanks!

 

[batman99]

My 96 Bayliner Capri 1700 with factory 120HP Force engine was sold to me with a 21P SS prop. Being a banged up prop, I replaced with 19P 3-blade and a 17P 4-blade Solar Aluminum (from iboats store). My 4-blade was so impressive for water sports, I kept it as my main prop. And, used 19P-3 blade as spare. If wondering, the Force 120 isn't a fast engine. Its really only 90 HP at the prop and its heavy weigh makes it harder to go on plane. My previous 1996 Force 120 on V-hull design would max out at 38 MPH (good day / with the wind on a light weight load). I replaced this 1996 Force 120 with a 1995 Johnson 115 V4 (much physically smaller size engine) with 19P 3-blade, and WOW!. Amazing before and after results. Long mumblings short..... I find the Force 120 isn't a very fast speed engine (due to its real world HP at the prop and it heavier size weight). Other brands of engines with near same HP stamp go much better....

 

[SkiDad]

35 is a little low - i would think you should be around 40 - that being said 5000 is a good rpm and if that is all it's turning you are not going to get much faster with a higher pitch prop unless something is up with that prop or your rpm is reading low. My guess from your numbers you are running a 17 pitch prop currently - but sometimes you have to remove the prop to see the numbers on it - could be under the front or rear washer.

 

[gmstreetmaster]

35 is a little low - i would think you should be around 40 - that being said 5000 is a good rpm and if that is all it's turning you are not going to get much faster with a higher pitch prop unless something is up with that prop or your rpm is reading low. My guess from your numbers you are running a 17 pitch prop currently - but sometimes you have to remove the prop to see the numbers on it - could be under the front or rear washer.

From what I was reading, the boat should be about 40 MPH stock as you stated. I will try to remove the prop and see if there is any numbers on it. If it is a 17 pitch now, do you think a 19 pitch would get me where I want to be? Or do you think a 21 would be needed?

 

[batman99]

IMO, many Bowrider design boats are tested / tuned with single driver and very little onboard fuel / very little onboard stuff. Thus, getting best test results one can get. In reality, many folks drive with full to 3/4 tank of gas, load up with supplies, their wife, their kids, their kid's friends, etc. etc. Since front bow seating is often too windy, larger size folks sit in rear seats. This put even more weight in rear of the boat - which lugs its engine. So in reality, the "perfect tested" factory prop isn't the right one for reality.. Try 19P 3-blade aluminum with your "average loaded" Bowrider. If it feels like its lugging too much, then go with 17P 3-blade. Yes. WOT RPM is the measuring meter. But, one has to feel the "sweet spot" (where it all feels best) as well. Some folks say a 17P 4 blade acts like the 18P-3 blade prop. then again, it depends on the exact brand of prop. I hear Solaris aluminum brand feels 1 pitch higher than props of same number. Long mumblings short... One needs to try multiple different xxP props to get the best feel for your unique situation.. Same as "not all shoes in size xx feel the same" either situation...

Forgot to mention.... I like to use the 80/20 rule. If "average loaded" heavy weight &/ or Water Sports 80% of the time, then size prop for WOT/max RPMs@ 5200 when average loaded. When lighter weight loaded, simply do NOT over rev it. Thus, sizing the prop for the majority of your usage condition.

Hope this helps - somehow...

 

[gmstreetmaster]

Thank you!

 

[gmstreetmaster]

I luckly found a 19 pitch 3 blade on craiglist off a Honda outboard for $65. Great shape too. Now at 5000 rpm I'm able to do 42mph. Still gets out on plane in the same amount of time as with the 17 pitch. I think if I come across a 21 pitch I may get that one too.

 

[jerryjerry05]

You should put this in the prop section.
The expert are there.