Why are some new engine couplers being supplied with what I consider inferior hardware? The bolts from my original coupler are flanged

with a 1/8" collar that assures a precision fit in the holes. What I got with my new coupler is a basic 3/8" partial thread fastener with washers.

For something as critical as an engine coupler, I feel this is unacceptable. The flanged bolts were purpose made to assure perfect alignment

on the flywheel. It may depend on what vendor is supplying the coupler as to the hardware that comes with it. Sierra for example.

The bolts you will get if you order from mercruiser are Quicksilver pn 10-14883. These are not the flanged bolts, and I won't use them!

Replacement bolts are very hard to find on line if you don't have a part number. If anyone knows where I can get the flange type of bolt, please

pass it on. Thank's!

Try............................https://www.mcmaster.com/

Arent they typically hardened?

The proper bolt is called a pressure plate bolt with a shoulder that aids in alignment. Some are flanged and some use a washer, which really doesn't matter. They appear to be partially threaded but in fact the shoulder is slightly larger in diameter and extends into the flywheel. ARP part number is 130-2201, but you can also use the GM version that is used on their manual transmission vehicles. Using a standard bolt (no matter how strong) will more than likely result in having the coupler be out of round and can cause severe vibration.

GF?

These are OE,

Alignment Bulletin 2009-11 uses taper head screws for centering.

Exactly. The flange isn't important, it's the collar! The flange is convenient anyway. I never thought of using pressure plate bolts, and that's good advice. I know the flywheel threads are recessed.

I ended up using grade 8 flanged bolts from Mc Master. I staggered 3 of the old collar bolts to get the alignment, then tightened 3 of the new bolts and so on. I don't want to seem like a know it all,

but instead of posting bulletins, why doesn't Mercury just supply the correct hardware? I thought my post would be helpful to my fellow boaters. I appreciate all the feedback!

This is a great website, just signed up and been searching the forums. Very insightful, I've been reading my Clymer Mercruiser manual and there is no mention of coupler bolts or run out. Looks like I'll be pulling the engine again......

Just installed the port engine back in my 1997 Scarab 29. Got the engine aligned with the alignment tool and then rotated the crank 180 deg. Bound up tight. Rotated back to 0 deg. and happy alignment again. Looks like the coupler is de-centered on the flywheel? I bought the boat as a basket case, and had to pull the engine out to fix several issues. Didn't think to check the coupler run out. Started searching and came across this website.

Anyone have a tolerance that is allowable? Someone here mentioned .005" but was that on the flange with the alignment tool as the pilot? I'll probably put a dial indicator somewhere on the coupler center and rotate the crank before I pull it back out (if I can get one down there).

Coupler inside hub spun. Need to replace. Anyone got an idea that would cause this on a bravo with only a 350 EFI?

Alignment wasn't checked
Should be checked yearly when changing the gear lube