Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: 1995 Dauntless 15 prop choice Yamaha 70 TLR
Posted by JimGregory on 08/09/20 - 4:10 PM
#1
Hi All
I recently got an old
1995 dauntless with a 2006 Yamaha 70 RTLR 2 stroke motor. The prop is a 13 1/4 x 17 3 blade unknown maker. Runs well but only got up to about 4500 rpm's full throttle. A little sluggish out of the hole but it is hard to hold a slow plane. I like running at about 17 knots but she drops off slowly. I have to run very fast to stay up.
SO I purchased a yamaha 3 blade 13 1/2 x 15, 3 blade. Looks like a semi chopper prop to me.
The original had big wide blades. The new prop runs up to about 5400 rpm and can hold a slow plane no problem. BUT it cavitates like mad at lower RPM's. The big eared original never cavitated. I believe I have 1 hole showing above the top bolt on the motor. Not sure where the cavitation plate is relative to the boat bottom, as it's been in the water since day 1.
What do you think?
New prop
https://www.amazon.com/Yamaha-Aluminu...B004S76F96
Edited by Joe Kriz on 08/09/20 - 5:47 PM
Posted by Phil T on 08/10/20 - 7:59 AM
#2
I think you mean ventilation, not cavitation.
Before doing anything, check the engine and report what mounting hole the engine is using. How many empty holes in the top bracket
above the engine bolt?
Brand and model of prop is important since size and performance is not universal. Part # is on the outside or inside of the hub.
Recommended prop for the Yamaha 70hp 2-stroke include:
13-1/4" x 15” Turbo 1
If you want to hold plane at lower speeds, many Dauntless owners have gone with 4 bladed prop.
Posted by MG56 on 08/10/20 - 9:09 AM
#3
Phil, he stated the engine is mounted one hole up.
Posted by Phil T on 08/10/20 - 9:33 AM
#4
I believe I have 1 hole showing
Good to be sure prior to purchasing a $3-600.00 prop.
Posted by jparmelee on 08/11/20 - 7:32 AM
#5
Very interested here as I have a 2005 Yamaha 70 TLRD 2 stroke motor on my 1978 Montauk 17, with what could be the same propeller (part no. 992104). I also think I am getting lower RPMs than expected (though with some rough seas and family onboard I haven't had it wide open recently).
Posted by JimGregory on 08/25/20 - 4:32 AM
#6
jparmelee wrote:
Very interested here as I have a 2005 Yamaha 70 TLRD 2 stroke motor on my 1978 Montauk 17, with what could be the same propeller (part no. 992104). I also think I am getting lower RPMs than expected (though with some rough seas and family onboard I haven't had it wide open recently).
Posted by JimGregory on 08/25/20 - 4:34 AM
#7
jparmelee wrote:
Very interested here as I have a 2005 Yamaha 70 TLRD 2 stroke motor on my 1978 Montauk 17, with what could be the same propeller (part no. 992104). I also think I am getting lower RPMs than expected (though with some rough seas and family onboard I haven't had it wide open recently).
You remind me of Parmalee honda in Fairfield CT.
I have finished sorting this out yet. Now I am playing with motor height.
Edited by JimGregory on 08/25/20 - 4:34 AM
Posted by jparmelee on 08/25/20 - 7:30 AM
#8
What prop did you end up going with?
Posted by JimGregory on 08/25/20 - 7:58 AM
#9
jparmelee wrote:
What prop did you end up going with?
Still on the 13.5 x 15-3 blade yamaha prop. Decided to square everything else away RE: motor height before buying any more props.
Posted by JimGregory on 08/31/20 - 7:48 AM
#10
jparmelee wrote:
What prop did you end up going with?
Staying with the 3 blade aluminum 13.5 x 15. I get now about 5500 rpm at 36 mph. Very fast for that tiny boat!