Drive coupler bolt question
 

During my final reassembly of my engine, I realized I've lost the bag containing the coupler to flywheel bolts and washers. The parts fiche lists them as 3/8-16 1"long. Would grade 8 be sufficient for this, or do I need a lower grade? What about the washer, is it a normal flat washer or split washer?


**Edit - It's for a HP500 and Bravo coupler.
Thanks,
Ryan

Pretty sure the bolts have a shoulder to locate the coupler on the flywheel. Not just your everyday bolt

correct,they are grade 8 bolt and use a lock washer.i also use blue lock tite on them.i have seen people use a non shoulder bolt but i don,t think it is a good idea.they would be the same bolts used to bolt a pressure plate on a flywheel.

Could be place bolts as well. Carroll Smith would probably also approve of good socket head cap screws, Unbrako or the like.

Thanks for the info.

I'll try calling the local marinas to see if they have any in stock, then the GM dealerships or speed shops to see if they have pressure plate bolts.

I had the bag with mine in it recently, but can't remember where I placed it. I tore the garage apart last night looking - as soon as I buy the replacements the originals will turn up. I plan to put the engine back in the boat on Thursday, so time is getting short.

Ryan

To close this out in case anyone is looking for the info in the future
3/8-16 1" long shoulder bolts, hardened (grade 8) with locking washers
Dorman: HPX 710-121
ARP: 130-2201
Mr. Gasket: 910
Mercruiser: 10-35091 (bolt)
Mercruiser: 12-20572 (washer)

My local speed shop carries the Mr. Gasket brand for ~$15 or so for a pack of 6 bolts/washers - Mercruiser is about $10-11 per bolt.

Ryan

this past winter i bought a bravo parts boat and stripped it. there were no shoulders on the 6 mount bolts. nor have i ever seen a shoulder on the 3 that mount alpha couplers. the only couplers i ever saw that i was sure were on center were the old ones that bolt to the flywheel hub.

I had the same problem. Went to my local Mercury dealer we looked at several different engine sizes with bravo drives and never found the shoulder type bolts. All they had were regular bolts not even grade 8. I can't remember the price but all 6 were about 12$. I measured the flywheel holes and the coupler holes and there was a difference. I made 3 stepped pins at work to algin the coupler and flywheel. Installed the bolts with blue loctite.