long or short shaft

[JustinG]

I have a 73 mod 25 horse johnson measures 18 inches from top of transom at clamps to cavatation plate, is this a long or short shaft? The plate is about 2 inches lower than hull of aluminum boat, is that the right fit?

 

[ob]

Re: long or short shaft

Sounds like a long shaft.Try to mount engine where the anti-ventilation plate is roughly even with bottom of boat.You'd like to get it as high as possible without experiencing ventilation of prop while executing sharp turns on plane at around 1/2 to 3/4 throttle.

 

[drod]

Re: long or short shaft

Your motor should be a long shaft. For more info on determining the shaft length, you might want to log on to this website : www.brokeboats.com go to TRIM & TILT and then scroll down to "Little info on motor height and shaft length" (shows a graphic for determining shaft length) hope this helps.

 

[Chinewalker]

Re: long or short shaft

If you engine is sitting on a short shaft transom and hangs only two inches below the bottom, then you've got a SHORT SHAFT. A long shaft would be at least 20-inches. OMC's are typically a couple inches on the long side of 15-inches (or 20 for a long shaft) to account for variations in boat transoms, keels, etc. <br /><br />The only way your '73 model 25hp would be a long shaft would be if it had a 5-inch tall extension bolted between the exhaust housing and lower unit.<br /><br />- Scott