Outboard size for 23.5

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Aug 5, 2020
1
Catalina 22 Jackson
Hi. I’ve been offered a great deal on a 15 HP outboard (25 inch shaft) that weighs in at 105 pounds. Is it too big for my Hunter 23.5? I don’t really plan to run it at full throttle. Any thoughts?
 
Feb 21, 2013
4,638
Hunter 46 Point Richmond, CA
Welcome to the forum!!

You need approximately 1 HP per 550 lb of displacement or 4 HP per 2200 lb. Since the Hunter 23.5 has a 3000 lb displacement a 6 hp motor long (20") or extra long (25") shaft works. Other forum members may have experience with a higher hp motors on that sailboat.

This article might be helpful. How to Calculate Outboard Motor Size for Sailboats
 
Last edited:
Apr 27, 2010
1,236
Hunter 23 Lake Wallenpaupack
I have a 23, not your boat. Came with an 80 lb Honda 8hp. Pretty heavy, so I'd think the larger motor may pose some drawbacks. Would you be able to tilt it up, or if you have or add a lifting motor mount it may be tough to lift it.
 
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Jun 2, 2004
3,390
Hunter 23.5 Fort Walton Yacht Club, Florida
Too much hp and too much weight

Maybe you can get it and trade it for a 6 or 8 hp motor
 
May 24, 2004
7,129
CC 30 South Florida
It depends on where do you intend to use the boat. In a lake 6 to 8HP will be plenty, if in a river or the ocean then an 8 to 10HP will be preferable. All these engines in 4 strokes will be close to 100 lbs. so make sure your motor mount is rated for that weight. More important than horsepower is the shaft length, I suggest you look for a 20" shaft length as will help keeping the prop in the water. Many 15HP manufacturers use similar engine components as their 10HP models so hence their weight is similar with a higher state of tune. Only a 6HP would be significantly lighter than the others with a weight of around 60 lbs. The bigger engines may be equipped with an electric starter and with the option of a larger alternator. What I am afraid of the 15HP is that it may not be appropriately propped for your sailboat. They are usually outfitted with a higher prop size that may result in higher fuel consumption with no increase in performance. It also may not allow for proper idle speed. In any instance each outboard/ boat combination requires a specific propeller size that will allow it to reach but not exceed maximum rated engine revolutions per minute. manufacturers usually equip their engines with a middle of the road size prop to accommodate a variety of boats. For sailboats they do a decent job in propping on the smaller engines but as they grow in horsepower they get more propped for planning hulls. Also consider how you are going to be using the engine; if only to get in and out of the dock and light use then a real good deal on the 15HP might be a good economic compromise. Do your homework and scout sales out of your immediate area.
 
Sep 15, 2013
707
Catalina 270 Baltimore
I had an Irwin 23. It had a 8 HP long shaft and it pushed it to hull speed just fine. I think 15 HP may be a little much. True you can throttle down but that is a lot of extra size and weight you don't need.
 
Jun 8, 2004
10,024
-na -NA Anywhere USA
Sailboat transoms were designed for motors rated at 10 ho max and that includes the 23.5. As for experience, max hp is 8 hp. Then you would need to beef up the outboard motor bracket. Please do not doubt me. I was involved with the design of the 23.5
 
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Sep 30, 2016
339
Island Packet IP 44 Ventura, CA
I have a 23.5 and I bought a Honda 8.0 hp. I wish I had gotten a 5-6 hp. 15 hp is way way to much. I cruise at hull speed at about 1/3 throttle. The only time Ive used full throttle is when I had to abort a docking attempt after a storm gust front tried to crash me into the dock. So, 8 is too much. 15 would be a waste, IMO.
 
Sep 25, 2018
258
Catalina Capri 22 Capri EXPO 14.2 1282 Stony Point
I had a 9.9 Honda. Needed it on the Hudson River many times. Gave away the boat but kept the motor. It's available in Mahwah NJ.
 
Sep 16, 2007
48
Hunter 23.5 lighthouse landing
I'd say that is WAY to big. I doubt the motor head will fit in engine well area. I have a '03 mercury 6 2-stroke. pushes the boat to hull speed 6ish kts. as far as weight goes. These lil hunters have a natural list to port. my motor is 80'ish lbs. house battery is 70 lbs and 3 gal fuel 26ish lbs. all on the port side. It lists pretty good sitting at the dock.
 
Jun 8, 2004
10,024
-na -NA Anywhere USA
The stainless steel brackets (2) which hold other motor mounts on the hunter water ballast sailboats are patterned to your bolt holes as well. Used them on the early boats to extend the motor mount out further so the motors could be tilted back further
 
Aug 1, 2021
47
Hunter 23.5 Lake Rathbun
Sailboat transoms were designed for motors rated at 10 ho max and that includes the 23.5. As for experience, max hp is 8 hp. Then you would need to beef up the outboard motor bracket. Please do not doubt me. I was involved with the design of the 23.5
I am looking to buy a 23.5 that comes with a Tohatsu 9.8hp. Seems too big and heavy so considering selling that motor and getting 6hp. Would that 20lb weight reduction be better for the boat or should I try living with a motor I can't pick up?
 
Jun 2, 2004
3,390
Hunter 23.5 Fort Walton Yacht Club, Florida
I am looking to buy a 23.5 that comes with a Tohatsu 9.8hp. Seems too big and heavy so considering selling that motor and getting 6hp. Would that 20lb weight reduction be better for the boat or should I try living with a motor I can't pick up?

Yes and Yes
Use it for now, look for a six hp motor and swap it when you find one
 
Jun 12, 2021
285
Hunter 240 Aqualand Marina, Lake Lanier
My H240 came with a 2006 Honda 8 hp outboard. It ran great the first two times then would not start. I checked everything electrical and figured that it must be the carburetor. I like the motor but it was to heavy to pull by myself. It weighs 90 lbs. I keep my boat in a slip and only use it go get in and out of the marina. I bought a 5 hp Mercury Propane and I would do it again. It moves the boat at it's hull speed and only weighs 57 pounds. $1,800 from West with the longer shaft and the charging system.
 

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Jun 12, 2021
285
Hunter 240 Aqualand Marina, Lake Lanier
Did you run ethanol or ethanol free gas?
The previous owner showed me the station in Jupiter Florida where he bought ethanol free gas and he had a bottle of stabilizer that he was using. I will be taking down the carb this winter seeing if I can figure of the issue. I wish that I would have brought back his outboard motor stand that the offered me but there was no room for it.
 
Apr 27, 2010
1,236
Hunter 23 Lake Wallenpaupack
If the 2006 Honda 8 is like my 1992, check the low speed jet first. On mine you can unscrew it from the top of the carb without removing any cables or hoses. Clean it out with a thin plastic probe and carb cleaner. It may just work, and save you a lot of disassembly labor.
 
Jun 12, 2021
285
Hunter 240 Aqualand Marina, Lake Lanier
If the 2006 Honda 8 is like my 1992, check the low speed jet first. On mine you can unscrew it from the top of the carb without removing any cables or hoses. Clean it out with a thin plastic probe and carb cleaner. It may just work, and save you a lot of disassembly labor.
Thank you so very much.