jakefromflorida

looking at a boat to buy right now...

Boat is great.

Motor runs great, I ran it idling, top end, all in between, cranked up several times... Seems legit.

I've heard these are the 2+ motors where only 2 cylinders fire to 1800rpms, then the others kick in...

My concern is when this motor is topped out sounds fine and run fine, every time I let off the throttle a slight rattle noise starts until the motor gets back under a certain amount then stops.

I've been told the shaft is about to explode and I'm looking at a new powerhead, then I've been told that's a normal noise for the boat... Can anyone help me?!

muskamoot

Do a compression test before buying.

chimmike

compression test won't tell you if the shaft is about to go.

UnitedYachtSalesVeroBeach

Mercury uses what they call a top guided connecting rod that does rattle when you let off.
these rods did correct a rod failure problem they had years ago

jakefromflorida

Compression was 150(3) and a 150... But like Mike said, I didn't suspect that to tell me anything. I'm just concerned with the crank, I've read where mercury used a unique connection link right below the flywheel which in some instances has broke and customers not even know it...

I told the guy I'm going to hold off and let him know in a couple days...