Re: 115 chrysler
It depends: Was the engine running on muffs or in the water? On muffs, they tend to take a good while to pump water out the idle relief holes, and sometimes they just will not prime. Thus, the engine will overheat even at idle. Sometimes on muffs, good high water pressure and flow is needed to get them to pump properly.
If it was in the water, it should have been pumping water out the idle relief almost immediately.
So: Let us assume that the water pump impeller is worn and not functioning. If the engine has been overheated to the point that damage was done, the paint will look scorched on the head and upper block. If it starts easily, runs well at idle, and looks well cared for, and if you are satisfied that it is a good gamble--and make no mistake buying ANY used boat and engine private sale is always a gamble of some sort--take a chance.
For your own piece of mind, do a compression check. If it has been overheated to the point of damage, compression will be low.
If you still feel the engine and boat are worth buying, a new impeller is less than 30 bucks and relatively easy to install.
