Re: 1966 Johnson 20 shaft length?
An FDL-20 would be a factory longshaft model, your model number indicates it's a short shaft. But to be sure, measure from the crux of the transom clamp (ie, where the engine sits on the top of the transom) to the flat plate just above the prop. If it measures under 15", it's a short shaft. 20" or over and it's a longshaft.<br />Also, if it's a longshaft, it should have a 5" section between the lower unit and the midsection.<br /><br />Some of these older Johnny/Rudes measure a little longer than they ought to. You can improve your performance by mounting them higher on the transom, but be careful that they can still draw water at idle and at full throttle. The little bypass plate above the antiventilation plate on the side of the lower unit must be submerged.<br /><br />Hope this helps!
