E-25 Johnson Extra Long Shaft Conversion

SURPRISE Deux, an Ericson 25 would not make sternway no matter what I tried. While looking though the manual I found out that the boat should be powered with an extra long shaft outboard. The previous owner had this sternway problem too, only his solution was to go with more power, a 15 hp long shaft up from a 9.9 hp; I can tell you that this did not work. A long shaft has a 20" shaft and an extra long shaft is 25" long. Unfortunately, it is very expensive to buy new conversion parts for a Johnson 15 hp; however, I was able to find used parts and completed the conversion. In the photo, the conversion has already been made and the old parts are shown, 20" shaft, 5" housing, water tube, and shift lever. The conversion parts ran about $400, and as long as it works, it will be well worth it. I will also be removing the adjustable motor mount and start the season with the motor hung directly in the transom cutout as originally designed. Hopefully this will make a big difference, but I won't know until spring.

Keep that prop close and deep

Our previous boat, a Niagara 26, had the outboard mounted on a cut-out on the port side. An extra-long-leg outboard was specified. It came with a Honda 10 and we later upgraded to a Yamaha 10 Hi Thrust.
This mounting kept the prop below the transom and we always had great power in either direction. Also note that putting the OB directly on the transom prevents cavitation when riding over big waves -- a real problem for any boat with a bracket-mounted motor. Keeping the prop closer to the hull is a big plus.

Loren in PDX

Loren:

Thanks for the advice, this is one area that I was looking for confirmation on. I remember from last season that the stern wake seemed to be highest right under the outboard and I was hoping that moving the outboard forward to the cut-out would put it in front of wate turbulance forming the wake. In other words, in the area with laminar water flow and opposed to turbulant water flow.