I normally carry a socket set, a set of ratcheting wrenches, a multimeter, pliers, dykes, ratcheting screwdriver and all the bits. Basically enough to be able to pull off the heads if need be Great thing about being a mechanic, I can fix just about anything if I have the part on hand, so I carry spare parts as well.

K-Y and sunscreen.

Everything else is just dead weight!

I didn't see a mention of metric wrenches so I have to ask: Are Mercruisers all SAE, so no need for metric tools? That would sure simplify things.

Good thread, went to Harbor Freight this evening and added some stuff that I was missing. Usually don't buy HB tools but for an extra set to keep on the boat I guess it'll be ok.