BBC only spins 180 degrees? Any ideas?
 

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so to make a long story short I’ve been working on a non-running project boat. This is the starboard motor that took me a while to free up. I had the motor running with good oil pressure. The next time I got to working on the boat the motor only spins 180 degrees by hand then I get a thud and hard stop. I have not hit the starter as i didn’t want to cause any bigger issues. The outdrives have been removed for winter storage. Nothing in the cylinder walls causing the issue.


any ideas what it could be hanging up on?

Drop the oil pan and look for metal shavings. In the pan and around the bearings. Run a magnet over that stuff to see if anything comes off. About the cheapest fixes would be a bad starter (stuck bendix spring). Or maybe an issue with flywheel. Worst case you have something with bearings, crank, connecting rod, etc going on.

You’re not that far away I’d consider going all the way down to the block. Know that it’s fixed and get any shavings gone.

A bent crankshaft will bind up like that.

Run an oil pump primer tool with a drill and see if anything changes and at the very least will confirm your pumps not broken off wedging against a crank journal. Lol. Can’t believe I just said that but I’ve seen stranger things!

Looks like it has to come apart anyway. You will find out soon enough.

Thanks for the great reply’s Xcommunic8d, Baja_260, getrdunn, and BillK

We thought about the possibility of the oil pump scenario as well 🤣.
Yeah working on how I’m going to get the motor pulled out, a task I’ve come to terms with but not looking forward to.

Bbc
 

I water locked an engine once, bent a connecting rod. An easy fix. However since you had it running before that, not to sure. It happened when I tried to start it, it fired once, hit the water, bent the rod,same symptoms. (Easy fix, pulled engine, disassembled,removed heads,easy.lol)

Bbc
 

Should be easy to tell if that's it, one piston won't come all the way up.

Kind of looks like it should come apart for a cam change anyway, no? Disclaimer, I didnt/cant blow the picture up/zoom in.

Pretty sure the Issue can be found in this book :wink


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