Correct mounting bolts for outboard?

[groundloop]

What bolts do you guys use for mounting outboards? Reason I ask is that I've been using stainless bolts with fine threads along with self locking nuts (the ones with nylon inserts), two times now when I've had to remove them I've had a couple of the nuts get boogered up and had to end up cutting them off with a grinder.

[gary slagle]

use antiseize on threads ,reduces the gauling when disassembled. stainless bolts,fine thread +nylock nuts is correct.

[johnboy 88 vegas]

The fine thread Yamaha bolts seem to work pretty well. Normal ss bolts from a hardware store seem to be a gamble if they are going to come loose without taking some threads with it. On a side note I see in your sig that you've dealt with Fast Frank before and I feel for ya. We see a lot of his junk come through the shop and most of it is tore up before the people even buy it. Its amazing someone hasen't "fixed" him yet b/c of all the people he's scammed.

[groundloop]

I got these bolts from Bolt Depot, I'm guessing they're more reliable than the corner hardware store. I hadn't thought of anti-seize, I should have.

I see in your sig that you've dealt with Fast Frank before and I feel for ya

Yeah, that asshole talks a good line. I was in the middle of rebuilding my Checkmate when I bought the engine from him, it sat for about 6 months until I was ready for it (projects always seem to take longer than they should). I was fully expecting to bolt the engine on and go have fun, damn did I ever get a rude awakening.

[1BadAction]

Mercs outboard mounting bolt kit is cheaper than buying the hardware separately and it has the correct bolts and nuts. 1/2" fine thread SS bolts, thick and thin washers, and brass locknuts. They will not gall up like stainless on stainless.

[activator22]

With BoltDepot and hardware stores, be careful of the SS grade. Yield and tensile strength of types 304 (aka18-8) and 316 are half or less of 17-4 SS chart of strengths here: http://www.onlinemetals.com/stainlessguide.cfm

ARP uses 17-4 . Can get them at Jegs/Summit/Allens Fasteners http://www.screamandfly.com/showthread.php?235123 and http://www.allensfasteners.com/detai...oduct_ID=0531B

[rev.ronnie]

With good quality stainless hardware, the locknuts are a different alloy than the bolts, this keeps them from galling. The nuts are harder...
Anti seize helps, but always retorque on a regular basis. Do the lower unit bolts as well, they will come loose real quick on surfacing prop applications.

[Revolution141]

I've always found the 1/2" bolts sloppy in the mounting holes and under stress mushroom the washers into the holes leaving the bolts slightly loose. I now use 14mm 316 course thread (for no other reason than they are easier to come by than fine thread) bolts, washers and nylock nuts and double bolt top of mount. These fit the standard merc bolt holes more snug (still 1mm clearance) and don't mushroom or stress the bolts.
I run a custom made setback and have 3/4" 316 stainless bolts and nylock nuts through the transom. I bent about 6 sets of 1/2" bolts before Finaly going this way.
I do run offshore and my engine cops a hiding! Even broke stbd mounting bracket on engine once.

[HStream1]

BINGO!!! When using SS to SS 304 SS bolts always use 316 SS Nuts. And always use Xtra thick washers to eliminate cupping. When the washers cup the bolts get loose.

I never use hardware store junk on stress related applications. Ace is better than most if you want one or two of a item. But I always buy from Fastenall when a quanity is needed.

With good quality stainless hardware, the locknuts are a different alloy than the bolts, this keeps them from galling. The nuts are harder...
Anti seize helps, but always retorque on a regular basis. Do the lower unit bolts as well, they will come loose real quick on surfacing prop applications.