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  Prop: Suzuki 140-HP

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Author Topic:   Prop: Suzuki 140-HP
darryl posted 12-24-2002 04:14 AM ET (US)   Profile for darryl   Send Email to darryl  
I plan to buy a Suzuki 140-HP 4-stroke for a 1986 18-OUTRAGE. What size stainless steel propeller is needed?. Thanks for the help. [This post was edited--jimh.]
Bigshot posted 12-24-2002 10:29 AM ET (US)     Profile for Bigshot  Send Email to Bigshot     
darryl That is not an answer we can answer because I do not think anyone here has that setup (but they should). that 140 has a real funky gear ratio and on a light boat like the 18" you may be running like a 24" pitch. My bud has twin 115's on his 23 seacraft which runs about 45 mph(about where you will be, you may be a bit faster). He runs 23" alum props at about $6k. I think your engine will turn 6200 so a 24" SS prop might be it. The dealer will know better and usually let you try different props(whether you buy the engine from him or not, just buy the prop from him, etc). keep us posted! I think that is the ULTIMATE 18' setup.
masbama posted 12-24-2002 12:28 PM ET (US)     Profile for masbama  Send Email to masbama     
Suggestion: Buy the Johnson model. White would look sweet and I bet you can get a better deal.
darryl posted 12-25-2002 03:08 AM ET (US)     Profile for darryl  Send Email to darryl     
where can I get a deal on a johnson 140. The johnson & suzuki are same motor. I think the suzuki is cheaper from Florida.
Peter posted 12-25-2002 09:52 AM ET (US)     Profile for Peter  Send Email to Peter     
The DF 140 has an equivalent final drive ratio of 2.38 achieved through a two stage reduction. The DF 115 has a final drive ratio of 2.59 also achieved through a two stage reduction.

Having had an 18 Outrage with a 150 Johnson running at a maximum speed of about 47 mph with the engine two holes up and about 44 mph with the engine one hole up, I don't believe that you will get more than about 42 mph out of the DF 140 at WOT. Plugging 6000 rpm, 2.38:1 gear ratio, 10 percent slip and 42 mph into the propeller calculator (see www.continuouswave.com/cgi-bin/propcalc.pl ) yields a pitch estimate of about 19.5 inches. Intuitively that seems about right. I believe that a 24" prop on the DF 140/18 Outrage combination will be too steep to allow the DF 140 to turn the required 6000 rpm.

Bigshot posted 12-26-2002 09:47 AM ET (US)     Profile for Bigshot  Send Email to Bigshot     
See....gonna be trial and error. Dealer will know best. Johnson/suzuki is the same engine sans paint. I have a dealer by me selling new 2002's for $7k.

Peter...many if not all here have quoted 18's with 150's doing over 50. Being it is only 300lbs heavier than a montauk, I think 42 is low being my 70 will fetch me almost 40 on a montauk.

Peter posted 12-26-2002 02:21 PM ET (US)     Profile for Peter  Send Email to Peter     
Bigs,

I don't believe that most have reported WOT speeds over 50 mph with the 18 Outrage/150 combination. I recollect more reports in the mid to high 40s. I ran a 14 1/4 x 21" prop to 5000 rpm at WOT and I never saw 50 on the GPS, not even when very lightly loaded. Perhaps my motor was weak for its entire life. Maybe without bottom paint and with a strong motor and a perfectly set jack plate you might get close.

Based on my experience with both the 18 Outrage and a 22 Revenge powered by a 225, I believe the tabular performance predictions for those hulls (see continuouswave.com/whaler/reference/performancePrediction.html ) based on the formula suggested by Clarke Roberts (see continuouswave.com/whaler/reference/prop2.html are pretty good. Looking at that table you'll note that the Montauk has a hull factor of 200 versus the Outrage/Revenge factor of 180, wherein the higher the number indicates a more efficient hull form. The formula using 200 as the hull factor predicts that 70 hp should push the Montauk to 40.1 mph. Sounds pretty close to what you are getting! That same formula using 180 as the hull factor predicts that the Outrage would require 125 hp (55 more hp than the Montauk requires)to push the 18 Outrage to the same 40.1 mph. Thus, because they have different hull factors, the performance of a Montauk is probably not a good gauge for estimating the performance of an Outrage even though it has a dry weight of only 300 additional pounds.

I agree that the right prop will be found through trial and error as that is usually standard operating procedure for good dealers. If the performance predictor (predicts 42.5 mph for the 18 Outrage/140 combination) and the prop calculator work as well as they seem to, then I suspect that a dealer would or should start with a 20" prop. Whatever prop size turns out to be correct, I don't think Darryl is going to see the high side of the 40s with a Suzuki DF 140 on his transom.

masbama posted 12-26-2002 07:03 PM ET (US)     Profile for masbama  Send Email to masbama     
Try Edsmarinesuperstore.com and there is a place in Fla.; Sunrise Marine or something like that. I hear these are two good dealers with good prices on a Johnson 140 4S.
jimh posted 12-27-2002 09:40 PM ET (US)     Profile for jimh  Send Email to jimh     
Peter,

That is an excellent and comprehensive answer to this question. Thanks for posting that article.

--jimh

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