A friend who forgot to winterize his boat has now what appears to be a cracked block.. He was just going to be taking out for the first time this year..

My question is being that it gets cooling water from the body of water you are in and no chance of running out, what more damage could happen is any.. the block is already cracked.. what else could go wrong..

If water is pumping through the system would he be able to use the boat for a few days of fishing on his vacation?

Chris

eh....IF it will run....probably would sink the boat if the bilge pump fails....

Runs well, a little spray off the pulley's and bilge is new with spare set right next to it at high level

Water in the oil wouldn't be a very good thing. It causes fast iron wear on the cylinder walls and crank journals, etcetera.

friends don't let friends crack their blocks.

Good one tpenfield...

DeepV he is buying a new engine and drive for it, upgrading the engine to a 7.4 from a 350 mag..

IF--

the crack is exclusively on the exterior of the block, so that NO water is getting in the oil,

AND--

enough water is getting thru the engine and risers to sufficiently keep it cool,

AND--

the water is not running into the boat faster than it can be pumped out---

AND--

the water's not getting all over the alternator (no sense ruining IT)...

then have fun! Like you said, what else can you hurt?

A friend of mine used a busted-but-JB-welded leaking Merc 2.5 for 5 years...

And it's not cracked in a place that will be stressed enough to crack more or break. I have seen a piston come through the side on a race engine, started as a crack, ended as a big hole and a big mess.

This is the thing I'd be most worried about. At 3k rpms, one piston is running up and down 375 times per minute, or over 5 times per second. If that piston head is even slightly out of whack due to a miniscule shift in the shape of the block, it'll take less than 1 second to completely fail and the engine is, best case, a steel sculpture. Worst case, a grenade.

Math Check . . .

The pistons go up and down with each revolution of the engine . . . so, "375 times per minute" = 375 RPM

3000 RPM means that each piston is going up/down 50 times per SECOND (3000RPM/60SPM=50RPS) and firing 25 times per second (4 stroke engine).

Nothing good can happen to this engine as has been stated. The potential for engine failure and the POSSIBLE resulting fire would be more than enough reason to cancel boating plans.

Friends don't let friends drive boats with cracked blocks

My bad. I was drinking beer when I did my math.