The short and inexpensive answer that we have used for 25 years now: use the main halyard! This has worked on all our various 15 hp 2-strokes (circa 80-90 lbs).
Obviously you need a harness of some sort on the motor
. We made ours out of 1 inch nylon webbing with a couple of those flat black plastic "buckles" to get it off and on the motor
. You position the dink amidships, just aft of the mast
. If the motor is on a bracket near the stern of your boat, hook the halyard
onto it, have a mate put enough tension on the halyard
to just lift
the motor off the mount and walk it slowly back until it is hanging above the dinghy
. Then jump down into it and have the mate slowly lower it onto the transom. Takes maybe one minute when you have done it a couple of times. Removal
is the reverse process. This works (IMO) better than a crane on the stern of the boat, especially if there is any sea causing the boat to pitch
-- much more motion back there!
The beauty of this system is that it costs nothing to set up... everything you need is already there, so give it a try!
Jim and Ann s/v Insatiable II lying Trinity Inlet, Cairns Qld Oz