outboard advice

[newbie8459]

I bought a 19' O'Day Mariner with a 6 hp Evinrude short shaft. I had some trouble moving it up river. It seems the prop was not catching enough water. Particularly when larger boats went by and created waves. Should this model be using a long shaft? What's the best way to tell whether a long or short shaft should be used? Just by measuring the transom?I'm also looking at a 3 hp Gamefisher (adjustable shaft length)as a backup. Any comments?Thanks

 

[Steve Braverman]

Prop needs to be in the water

When I bought my O'Day 25, it had a 9.9 Johnson with an extra-long shaft (25"). However, the bracket was too high on the transom, and the prop would come out of the water often. I could not have anybody on the bow while under power, and I was advised to always keep all my tanks full. I replaced the engine last year with a new Yamaha 9.9, also with a 25" shaft, but I lowered the bracket on the transom. The previous owner had already lowered the bracket some with a wedge, but he was reluctant to lower it any more because he and his wife have short arms and could not reach the shift lever on the side of the cowl. The Yamaha has the shift on the end of the tiller.Your problem most likely is not the motor, but how it's mounted. The cavitation plate (the horizontal fin above the prop) must sit at lest 3-4" below the surface. You may get away with a short-shaft engine, but the controls may be too low and hard to reach from the cockpit. When you get the engine wounted properly, a 6hp should be more than enough for your boat.

 

[Mike]

Always

I think all sailboats big enough to need an outboard need a long shaft model. There are really two sizes of long shaft: 20" and 25". The 20" is much more common. I have found that the outboard brackets on most sailboats are properly placed so that a 20" outboard will have the prop and cavitation plate fully underwater when the bracket is at its lowest position. The 25" models will keep the prop in the water under more conditions. I almost never raise or lower the bracket itself; despite the spring loading on the unit, it is way too heavy and inconvenient to use. I tilt the outboard out of the water and always leave the bracket at the lowest setting.

 

[Jon6440]

Wrong Prop?

Before you buy (or try) the Long-Shaft Model of the 6-hp Evenrude, maybe you find a higher thrust propeller. I had a 6-hp (long shaft) E'rude on a Catalina 22, and it couldn't do much against a head wind. Then on an O'Day 240, I had a 9-hp long-shaft E-rude. Again pretty wimpy forward thrust. For free via complaint to the factory, the dealer swapped props. That helped, but cut fuel economy. I eneded-up after 1-year's experience, trading the 9-hp two-stroke E'rude, in for an 8-hp Honda 4-stroke. Amazing gain in Forward AND REVERSE thrust, and fuel economy!

 

[Dave K]

Motor probably too high

I use a 2hp Honda standard shaft on my O'day 192 which is similar in weight and size to your Mariner. When I first tried that motor it would barely move the boat because the prop was just under the water's surface. I had to modify the mount to lower the motor 5-6 inches and it now the little 2hp engine will push the boat at 5 knots. So my guess is that you have plenty of horsepower, but the short shaft/mount combination is not letting you turn that power into thrust. If that 3hp Gamefisher can be configured as a long shaft it might propel the boat better than the 6hp and it would certainly be easier to carry around.