Outboard Size

[ClassicalBGP]

I have ran a couple of search, yet I did not see an answer (a lot of useful info, but no answer).

I have an American Mariner 24' that displaces something like 4,300#. Plus, people, gear, etc.... I have only had the boat on a lake using a 6 h.p. outboard to come in and out of the marina. I posted late summer asking for help, due to the 6 h.p. not starting and leaving the us on the dock. Its in the shop now, however told the family I was getting a new outboard. While, I was happy with the 6h.p. on the lake, I want to take the boat to the MS Gulf Coast this summer. Taking into consideration, the boat, wind, tide, etc....

What H.P. (and or brand) should I be looking for? I was thinking Honda 9.9, but worry that it will not handle tides, currents, etc.... I did read the thread about H.P. vs fuel consumption in relation to speed. But, still will the 9.9 do what needs to be done? Or would a 15 H.P. be better?

[Cormorant]

I recall hearing a rule of thumb for displacement cruising of 1HP per 500 lbs. So that would point to an 8HP or 9.9HP for you.

My 31' 5000lb. boat (fully loaded) has a 9.9 Nissan and we are able to motor into most any headwind I would care to be out in. . . .

One thought is to look at the Yamaha 9.9 high-thrust motor. Better gearing for slow powerful cruising, and a bigger prop, I believe.

[Don C L]

I had a Columbia 24, and now have a 29, both with outboards. A 9.9 with a power prop would be more than you need but since it is only a little more weight than an 8, I say take Cormorants advice and get the 9.9 with the power prop.

[hobopacket]

+1 9.9 high thrust.

I had a 6 hp on my Catalina 22. Above 1/3 throttle was never needed.

[tkeithlu]

How fast does your present engine move you? Your hull speed is about 6.4 knots, so any engine that pushes you above that is a waste. Yes on the power prop for whatever you get. The engine is likely to be propped for pushing a dinghy.

[a64pilot]

9.9 is plenty, ideally in my opinion you pick a motor that gives plenty of thrust at half or less throttle, it makes way less noise there, burns less fuel and will last much longer than one that is often run at or near wide open, but I think a 9.9 will do that for you.
Be sure to get a long shaft and high thrust, that should not be propped for a dinghy, a high thrust motor turns a much larger prop at lower RPM which is exactly what you want for pushing power, but not planning speeds.
Brand wise, many are Tohatsu's anyway with different cowls and stickers so why not buy a Tohatsu?
Honda's are in my opinion overpriced as are Yamaha's, but that depends on the deal you can get of course, but I'd personally rather have a Yamaha over a Honda.
Does Suzuki make a high thrust?

[jeremiason]

Originally Posted by tkeithlu

How fast does your present engine move you? Your hull speed is about 6.4 knots, so any engine that pushes you above that is a waste. Yes on the power prop for whatever you get. The engine is likely to be propped for pushing a dinghy.

Not exactly true... Speed isn't as important as power, especially in sloppy seas or higher winds.

When I was sailing on SF Bay people were buying J24s off lakes that 6hp outboards...

Once on the bay with the waves and higher winds, they always converted to 9.9hp

[ClassicalBGP]

Originally Posted by tkeithlu

How fast does your present engine move you? Your hull speed is about 6.4 knots, so any engine that pushes you above that is a waste. Yes on the power prop for whatever you get. The engine is likely to be propped for pushing a dinghy.

My 6 h.p. Johnson pushes the boat about 3-4 knots (guess) at 1/2 throttle.

Can I buy a Long shaft and put a new prop on it or do I need to look for a special "thrust" model?

[valhalla360]

Ideally, you want a bit more than power than is needed to hit hull speed so you can overcome headwinds and waves.

Don't go crazy big as an engine run at low power will foul out the plugs (even 4 strokes but especially 2 strokes).

The 9.9 is probably a good option as they are common and easy to find used with enough power to fight a pretty good headwind on the boat you have. While a dedicated high thrust model would be better simply switching to a low pitch work prop will make a big difference.

[Cormorant]

Originally Posted by ClassicalBGP

Can I buy a Long shaft and put a new prop on it or do I need to look for a special "thrust" model?

The high-thrust models are geared ideally for slow heavy work like pushing a sailboat. They'll have larger diameter props with larger surface area. They won't get a jonboat up on plane at 25 mph -- and that's not what you want.

They're like driving a car in first gear -- all power and no speed. Putting a bigger prop on a standard outboard is like trying to drive your car from a dead stop using second gear, or trying to go up a steep hill in fourth . . . You might do it, but it's not an ideal application the the engine's power.

The only thing is the high-thrust outboards often cost more than the regular ones. You might want to hunt around for a used one in good condition.

[Benz]

I use a high-thrust 8hp Yamaha on my 20,000# 31-footer. If you can find a 6-hp High Thrust (Yamaha makes or made one), you'll be all set. Whatever you get, make sure it's high-thrust. That is all the difference in the world.
Ben
zartmancruising.com

[Boatguy30]

The T8 Yamaha is a great motor. The new 9.9 is the same motor with different carb and prop. The T8 carb is simpler and more reliable and the lower pitch prop is better for heavier boats.

Yamaha never made a 6hp high thrust, they did make a dual thrust prop for the 6hp 2 stroke.

[JeffDPT]

My Yamaha 9.9 pushed me a hull speed on Seaward 24 in LI sound under moderate conditions. No complaints. Good luck

[tenchiki]

I have a Dolphin-24 (about 4300lbs designed) with a Yamaha 8-high-thrust. I sail on San Francisco Bay. It pushes at over 5 knots at < 1/2 throttle most of the time. It doesn't take much throttle increase to handle pretty strong head winds. I think a smaller/lighter high-thrust motor would be more appropriate.

[ClassicalBGP]

High thrust- 8 to 9.9. Once again thank you to all for the guidance and wisdom