Well, I was not planning on rebuilding this motor. However, I agree the crank appears to be cracked.
This is an Indmar engine, using a GMC 5.7 Vortec block. What aspects of this motor is different from a mercruiser? Where do you suggest we order parts from?
both are General Motors truck motors, blocks, heads and rotating assemblies.
from there Indmar bolts on their intake manifold, their exhaust manifolds, all their accessories, etc. they may also spec a different cam.
Mercruiser gets the same General Motors truck block, rotating assembly, heads, and the stock GM cam. then they bolt their bits to the motor.
Indmar generally is a hotter engine than mercruiser
Can you expand on that, are you suggesting a “two piece” crankshaft? In other words a crankshaft with a “snout” attached to the end? Or are you saying that it is broken and you are using the “snout” as a door stop?
the crank is junk. and if the motor was running with a broken crank. my guess is that at least 1 or two rods are now junk too. bearing cap may be junk. block will need to be inspected.
generally a crank breaks from a bad or poor balance job and a slight imperfection in the crank.
a slight imbalance and the imperfection simply start a crack at the stress riser and after a few thousand cycles (rotations) the crack starts to go. it may take 20 hours of cycling for the crack to start. however it only takes a few cycles after that for the crack to propagate thru the crank.
of the broken cranks I have had over the years. 2 were casting inclusions (buick cranks), about 5 were a nick in the radius from welding/grinding, the remainder were abuse ranging from too much go-juice to just a slight over-pressure to way over-reving from missing a downshift
