Outboard motor size

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Robert A. Miller

Am interested in a 4 stroke engine for my O'Day 23 (1978). What horsepower would be best for this boat?
 
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Warren

I have had my O'Day 22 for 29 years. I started out with a Johnson 3 hp, I was on the Hudson River, the 3 hp worked fine. The only time I could have used more power was when I was motoring against a strong tide. After the 3 hp, I had a Volvo 9.9 hp,(very similar to an OMC engine) this engine put out more than enought power. After the Volvo, I purchased a new Evinrude 6 hp, my current engine. The 6 hp seems about perfect. Evinrude/Johnson market the same basic block in an 8 hp. All my engines have been 2 stroke for one very good reason...lighter weight! If you are going to "hang" your engine off the transom on a outboard bracket, it is to your benefit to get the lightest engine for a given HP. I also like the idea of the 4 stroke, however, unless your really going to do a heck of alot of motoring, the 2 stroke is the way to go. The 4 stroke engines are all quite heavy for their HP when compared to the same HP 2 stroke. I would suggest your take a look at a Evirude or Johnson 2 stroke in the 6-8 hp range. With a long shaft the weight will still be under 60 lbs. If you want to discuss this further, my E-Mail is skyking22@aopa.net Good Luck! Warren
 
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Mike

Careful with those 4 strokes

Remember that a four stroke of any given horsepower delivers more torque than the equivalent two stroke. This means you can probably get away with a smaller engine, which as the previous writer points out, is good because the smaller engine will weigh less. If you do buy a four stroke, you must make sure that your engine mount bracket can handle a four stroke. If your bracket is original equipment, or even if it is more than about five years old, it cannot handle the torque of a four stroke and must be replaced. This can be a pain, as I recently found out. Rudy at D&R can sell you a mount that has the same bolt spacing as the original, so that you will not have to redrill. Also, make sure that the fiberglass spacer block (that funny looking wedge on the transom) is in good shape. Mine was seriously cracking internally and needed a lot of epoxy to solidify it. As far as the size of the engine, I have a two stroke 9.9 on my '79 O'Day 23, and it is plenty of power, maybe too much. I have had people with more experience tell me that a 6 would be fine. I imagine that a four stroke 6 would be plenty.
 
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Bob Bennett

WaterSki Behind Your Oday 25

My boat partner/brother in law and I are in our mid fifties. Our old pull start motor was out to kill us for sure. The old 8hp was also a real polluter. Being ecologically minded we wanted a clean 4 stroke, a new one with an electric starter. So we coughed up $2400.00(twice what a new 2 stroke costs)for a new 9.9hp 4 stroke " Sail Power " long shaft Evinrude. It's huge,it takes two to lift it and three to set it on the old braket. Once on the braket, it took a 3way purchase with 2 blocks to "get it up". I ordered a new bracket "especially made for 4 stroke motors". Of course it didn't fit the old screw holes and we made an angled spacer out of mahogony because the old fiberglass one didn't work. I put in a new plywood and aluminum backer plate inside the hull. Everything back in place, we heaved the thing on the new braket and lowered it toward the water. The damn prop was barely below the water. The installation was by the book, so how could the prop work if it wasn't submerged? I hooked the leads to the battery and pushed the start button and the motor magically started. I put in in reverse, the prop barely flicking the water, then into forward. Slowly I gave it gas and then again as if by magic, the prop dug into the water and the whole stern and moter lowered into the water, we were moving! Some how the horizontal fins above the prop made it suck down into the water. We now make a rooster tail going 8 knots. We really haven't tried to waterski, and I literally cut the end of my left index finger off and had to get it stiched back on while lifting the motor to the up position,but now people ask " is that thing suppose to be on a boat that size". I say " Yes it is, besides, we couldn't get it off anyway !
 
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Robert A. Miller

Reply to Careful w/ 4 strokes

Mike, Thanks for the caveats regarding switching to a 4 stroke. I had thought about the motor mount issue but had considered weight more important than torque. Our current motor is very old and very heavy (I would guess 75 lbs. or more). The 4 strokes we are considering weigh somewhere between 40 and 60 pounds. I am not familiar with "D and R". Could you give me more information? Thanks.
 
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Mike

D&R

I once had an engineer explain to me what "torque" is and why it matters, but I confess that I have forgotten his technical answer. In any case, according to those more knowledgable than myself, the torque on a "lighweight" four stroke can bend, fold, spindle and mutilate your heavy duty two stroke bracket. D&R Marine is a boat yard in Massachusetts run by Rudy NIckerson. His phone number is (508) 644-3001. Rudy used to work for O'Day, and bought the molds for much of the replacement parts you might need (centerboard, rudder, etc.). He also has the original specs for things like standing rigging, and can help you with information as you do your own repairs. I bought a replacement outboard bracket from Rudy because I did not want to have to drill new mounting holes through my hull, and I could not find any chandlery that had many brackets in stock so that I could see their mounting dimensions. Rudy knew what those dimensions were, and had identiifed a replacment. I got a very good mount at an ok (not great) price. In my book, its worth the slightly higher price to get real expert advice. By the way, my new mount can handle a four stroke and cost $150.
 
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Andres Mamontoff

Go for the Honda 5HP 4 stoke

Just replaced my old Evinrude 9.9 (84 model) with a Honda 4 stroke single cylinder 5HP. I could not belive how well this little four stroke pushed. Much better than the bigger 2 cycle. At about 3000 rpm I was cruising at 2.5 knots. At 4000 rpm I was doing 3 knots. The old Evinrude hardly ever got to 3 knots. The Honda has max rpm range of 5000. The only draw back is that if you need to stop don't count on the Honda to slow you down in a hurry, better come to the dock slow, wich is hard to do because the Honda at idle goes 1/2 a knot. Plan ahead as you aproach the slip. The Honda doesn't lock and the porp will come out of the water if you rev it up in reverse. Another advantage is the weight. Honda 61 lbs, old Evinrude 95 lb. Full tank of gass for Honda 3gl (18lb) Evinrude 5gl (30lb) Other advantges, much quieter, no smoke, and one person can take the engine off because of its light weight. The old En=vinrude had good compression on both cilinders but was overheating, the impeller was ok but no water was coming out on the other end, to many years in salt water did him in. At $1500 the Honda is a great value and you can put it on a dingy and have two boats and one engine. Andres andres@mamontoff.com
 
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