Power head mounting bolts.

[Mark42]

In the fall of '05 I remounted the powerhead on my 40hp. The bolts that were used were not stainless and the heads had rusted from exposure to the salt. I cleaned up the bolts on a wire wheel, sprayed some Rustolium on the heads and re-installed them with a dab of anti-seize on the threads.<br /><br />I am wondering if I should replace those bolts with the stainless steel bolts offered in the powerhead bolt kits. I don't mind taking the time and the expense is low. I'm more concerned about making sure the threads in the powerhead don't get galled or messed up from using the wrong hardware. <br /><br />Thanks,<br />Mark

 

[R.Johnson]

Re: Power head mounting bolts.

That would be a good idea. A rusted, and stuck bolt in aluminum can give you a miserable time.

 

[Dhadley]

Re: Power head mounting bolts.

Ditto. You know yours will come out easy now. I'd do it. Especially considering how nice the rest of the boat is.

 

[tashasdaddy]

Re: Power head mounting bolts.

double ditto.

 

[Paul Moir]

Re: Power head mounting bolts.

I like to use socket head cap screws since sometimes those powerhead screws are hard to get at. They're actually stronger than hex heads, but that doesn't really matter at all. Any good nut & bolt place should be able to set you up.<br />Galvanic corrosion between stainless & aluminium is actually worse than between steel and aluminium. The most important thing is to grease/anti-sieze or use sealant on the bolt's threads to keep the water out.

 

[surlyjoe]

Re: Power head mounting bolts.

the grease and paint will probably keep the bolts like new, I would rather deal with possibly rusty steel heads than possibly powdered aluminum. The only time I use stainless in aluminum is if its exposed to the weather, and then grease the crap outa it!

 

[Moody Blue]

Re: Power head mounting bolts.

I would also be concerned about the galvanic corrosion issue. Aluminum and S/S are on oposite ends of the galvanic chart meaning they are highly suceptable to galvanic corrosion. The aluminum is the sacrificial component in this combination. Not sure what role the zinc anode (if you have one) on the motor would play in preventing the galvanic action. Check with your local dealer/repair shops for their opinions. Sure glad I don't have to deal with the salt water issue here.

 

[Paul Moir]

Re: Power head mounting bolts.

The zinc anode doesn't do dittley squat when you thread a stainless fastener into an outboard. It's just too far away electrically.<br />High grade (regular) steel fasteners are the responsible things to use. But they won't be shiney. And that's what really matters. <br /><br />(I should add, an ounce of prevention - that sealant/antisieze - really overrides the importance your metals choice. As long as the water isn't there, the corrosion isn't either.)

 

[Chris1956]

Re: Power head mounting bolts.

This is an interesting topic, so let me ask a question. My '59 Fat-Fifty had all stainless and brass fasteners. No steel bolts or screws at all. The headbolts were SS, the screws that held the outer casing together were SS etc. That motor had never been disassembled, but in 1993 or so, I dropped it into the bay(saltwater) while it was running. So after I found it 3 days later, I knew I had to take it apart to clean out the salt and silt. Actually my plan was to try to take it apart, assuming all the bolts would break, and then junk it. Surprisingly all the bolts came out without any coaxing. The screws also came out easily, with a hand impact driver. Why was this easy to disassemble? Did Johnson use a special aluminum alloy for the block and casing?