Hello

due to some unusual circumstances I ended up with a 14 foot jon boat (it takes a short shaft 15" transom) and a motor that is 20" transom.  I was hoping someone could tell me what the draw back to the set up would be? 

thanks

Jim

You're motor is going to be sticking an extra 5 inches below the bottom of the boat. In deep water, other than running a little slower from the drag, no major problems at slower speeds, but the anticav plate can cause some strange handling problems at speed.

It also greatly increases the chance of damaging the lower unit/prop in shallow water.

I would suggest selling the motor and getting a short shaft.

If it's an older OMC (Johnson/Evinrude), they have a 5" adapter.  Take it out, get another drive shaft or have that one cut and welded and shorting the water pump tube and shift rod and you turn a long shaft into a short shaft.  I've done several of those.

I have also seen where someone will add 5" to the top of the transom where the motor mounts. A lot of jet boaters will do that.

Look here

I saw a jet drive outboard motor setup last week where the only modification was adding a jack plate without increasing the transom height.

Jack-up/set-back plates are fully adjustable for height

thanks guys

I think its time to price a jack plate

or see if I can find a swap on the motor

shadrac