The 15" shaft will put the prop higher than the 20". If you need to lower it,
you may be able to cut the transom. If you really need to raise it, the jack
plate will do the job but it will also put the motor a few inches farther back.
That might throw off the balance if the boat is really that small and it
might even require longer steering and throttle cables.

If your dealer sells a lot of outboards, you will probably save more money by
having them take it in as a trade compared to buying the new parts and paying
for the labor to shorten it.

Dan



RG wrote:
In this case, I need to LOWER it. RG