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Author Topic:   Prop for Whaler 27
Rick U posted 12-22-2003 10:37 PM ET (US)   Profile for Rick U   Send Email to Rick U  
I have a 1988 Whaler 27 (notched transom) that I am re powering with 250 HPDIís. Iím almost ready to start considering propellers. Does anyone know the approximate weight of this model? Itís equipped with the 175-gallon fuel tank (full) and I have a 50-gallon bait tank (full) and not sure how much fresh water but it was also full. Do I really need to know the weight of the boat? I currently have the 13 ĺ x 17ís that were off my 88 Yamaha 200ís. I was turning 5300 and 5500 was getting 43mph. The gear ratio on the new outboards is 1.81. Is this enough info to get recommendations for propellers?
Sal DiMercurio posted 12-22-2003 11:25 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
Rick, start with the props you have & break the engine in.
My thoughts are those 250s will swing 13.75 x 19s, but being you already have the 17s just see how high those engines rev while trimmed out & a normal load.
If the 13.75 x 17s run 200 over maximum recommended rpms then you will need to go to 19p.
Just come back here & let us know your results so we can adjust to perfection.
Sal
Rick U posted 12-22-2003 11:38 PM ET (US)     Profile for Rick U  Send Email to Rick U     
Thanks Sal.
Thatís exactly what I have done. I have 12 hours on the motors with the old props and finally opened them up Sunday. I think I need to adjust one of the throttle cables because one motor was able to turn faster (by 300 Ė 400 rpm at the top end) than the other. Normal operating range is 4500 Ė 5500 rpm. At one point I got up to 5800 on one motor. Is that where it topped out is did the rev limiter kick in?
Peter posted 12-23-2003 10:17 AM ET (US)     Profile for Peter  Send Email to Peter     
Rick,

I run 2002 Evinrude 225s on a 27 Whaler with Whaler Drive. The engines are turning 14.75 x 19 propellers through a 1.86:1 drive. Top speed with a nearly full load of fuel (310 gallons is full) and water is 44 MPH. I suspect that top speed with a light load will come in around 47 - 48 MPH. I think your boat without the WD should be a little faster with the same power.

The propellers off of your old 200s are too small and are clearly not getting a good bite. Your higher RPMs on one motor may mean one motor is ventilating due to poor bite. That could be caused by incorrect toe-in. Also, if the engines are not in-sync, one of the propellers is going to be a drag for the other.

I think that any propeller with a diameter less than about 14.25 inches is going to be too small for those new motors having a 3.3L displacement rather than the 2.6L displacement of the old motors. With the extra displacement, your 250 HPDIs should be able to turn 15.25 x 19 Yamaha Saltwater Series propellers, or equivalents, through the 1.81:1 drive to the high side of the WOT range. Because you don't have the Whaler Drive and only have a 175 gallon tank, you might even be able to run 14.75-15 x 21 inch propellers.

I wouldn't adjust the throttle cables until you try larger diameter propellers with a minimum of 19 inch pitch.

I think the water tank is 30 gallons.

Rick U posted 12-23-2003 04:26 PM ET (US)     Profile for Rick U  Send Email to Rick U     
Thanks guys

Was informed this morning that I need a new power head.
Still in shock!

Sal DiMercurio posted 12-23-2003 07:13 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
The rev limiter should shut the engine down when you reach [ I think on the Yamaha ] 6,000 or 6,200 rpms. not 5,800.
Personally I feel Merc makes the best props out of the big 3 engine makers & Merc props do fit on Yamahas when hubbed for a Merc.
I would make sure those engines reach 5,500 rpms each while trimmed out & normal running load so they will run without being strained by over proping & only reaching say 5,000 rpms.
I agree with Peter as those engines will twist a 15" diameter just as easy as a 13.75" because you don't loose near as much RPMS when going larger in diameter as you do in pitch.
Sal
Rick U posted 12-23-2003 08:58 PM ET (US)     Profile for Rick U  Send Email to Rick U     
Sal are you saying Merc props fit on Yamaha motors or do I need a special hub? Also any recomendation where to buy Merc props online? Thanks
Sal DiMercurio posted 12-23-2003 09:06 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
Every Merc prop i'v tried on a Yamaha has fit like a glove & vise versa.
I don't have any sites for Merc or Yamaha props but I thing Ihg or Bigshot know of some.
Plus, Merc has the new Universal hub deal & they hub it for you for any engine your putting it on.
The Merc splines match the Yamaha splines & their interchangable on every single one i'v tried, like 20 props.
Mercs props are not cheap by a long shot, but their the best for the price unless you can get Stilettos [ $249.00 no tx ] to fit.
Sal

John from Madison CT posted 12-25-2003 07:26 PM ET (US)     Profile for John from Madison CT  Send Email to John from Madison CT     
Rick U: I believe you should go for the Yamaha Saltwater Series Props in 15.25" x 19".

This is a great question to ask over at: www.thehulltruth.com lots of Prop experts there.


John

Deanster posted 12-29-2003 03:10 PM ET (US)     Profile for Deanster  Send Email to Deanster     
My 1989 27' Center Console Cuddy weighs in at almost exactly 10K lbs with a half-tank of fuel, and I've got OMC 3-blade SS 15.25x19 props on my Johnson 300hp's.

41kts/47mph at 5100rpm with a light load.

I'm hesitant to contradict Sal, but my experience is that the big engines need ~15" props to transmit their full torque. If I remember correctly, the big Suzukis are even set up for 16" props.

I'd also note that many many folks have reported being happier with 4-blade props for the big boats - just a thought, as I haven't tried it yet.

Good luck.

Rick U posted 12-29-2003 09:31 PM ET (US)     Profile for Rick U  Send Email to Rick U     
Thanks for all the replies. I was reading a little about the 4 blade props and they sound good but I just donít know enough about them. I remember reading about a place that lets you buy props over the Internet, try them and send them back in exchange for a different size. Does anyone know who offers that service?

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