Mercruiser 898 v8 350 not starting. Is engine seized?

[amcfad2]

So I bought a project boat for very cheap. It has a Mercruiser 898 V8 Chevy 350 engine. Was told boat had a "wiring issue". There was an obvious issue with the ignition coil which I replaced. I drained the gas and changed the oil. New spark plugs and battery and ignition. When I attempted to start it, it just made a "clunk" noise. I pulled the starter and got it tested at the local O-Reily and it worked, but the solenoid had some rust and we thought maybe the connections were bad. Just put in the new starter and same "clunk" boat will not start.

I'm starting to think the engine might be seized. I put a breaker bar on the main crankshaft bolt and turned it. The bolt turns (it was actually kind of loose). Is this supposed to turn the main belt? The belt has not moved.

Anyone have any suggestions?

 

[achris]

898 is a 305, not a 350. Anyway, pull the drive off and try again. If it's still locked up, try running some oil into the cylinders and let it sit overnight. If that doesn't help is probably an engine out job.

Chris. ...

 

[Bt Doctur]

And never try to turn a motor over by using the cranks nose bolt. You will snap it off in the crank . Remove the drive and use a T bar with a old inputshaft welded to
or remove the harmonic balancer and use the correct crankshaft socket to turn the motor.
And if all else fails remove the 3 bolts for the harnonic balancer pully and install 3 long bolts and use a pipe between the bolts to turn the motor.

 

[wahlejim]

Did you happen to notice if any water came out with the plugs? What did the old plugs look like?

 

[amcfad2]

Did you happen to notice if any water came out with the plugs? What did the old plugs look like?

There was a little water in one of the cylinders, but not a substantial amount. 1 or 2 of the plugs had some rust. When I drained the oil, it seemed like there was a lot of water coming out with that...

 

[Scott Danforth]

There was a little water in one of the cylinders, but not a substantial amount. 1 or 2 of the plugs had some rust. When I drained the oil, it seemed like there was a lot of water coming out with that...

Pretty sure at best your motor is a core. If the motor has been sitting with water in the crankcase and cylinders for more than a day or two, the rings are rusted to the bore.

I would look for a replacement motor

 

[wahlejim]

Yep, it is either a tear down and rebuild or replace at this point. Even if you get oil in the cylinders and are able to eventually turn it, your compression numbers will be way off with some dead cylinders. I would re-power with a more recent, reliable motor. Possibly even upgrade to a 350 over the 305.