Restore my freeby!

[Vintage IRA]

A buddy at work lost a cylinder in his 90Hp Johnson. He ordered a new one and gave me his hirt motor. The Power head is in pieces and now I have to put Humpty back together again. Bores are all at 3.5 with one having some extra Aluminium in it. I'm told wiping down that cylinder with Boric Acid will remove the Aluminium before I hone the cylinder. Anyone hear of this trick?
I've built chevys before so this is my first Outboard rebuild.

Dano

 

[Vintage IRA]

Re: Restore my freeby!

Had the wrong acid, What about Muriatic Acid?

dano

 

[jonesg]

Re: Restore my freeby!

They usually bore oversize to match the next size piston and ring set.
A marine machine shop will bore it and machine the ports.

 

[emdsapmgr]

Re: Restore my freeby!

A marine shop I know of does use some type of acid to remove trace aluminum residue from (scuffed) cast iron cylinder walls. It does work and save boring, if the cyl walls are not tapered out of spec. You must replace that scuffed piston, however.

 

[parrisw]

Re: Restore my freeby!

Yes you can. Use muratic acic. I do it all the time on chainsaw cylinders, they are NiSi plated. And if the bores are ok, and you want to get away without machining I say go for it. Throwing a pile of money at something isn't always the only way to fix something. Apply the acid with a Q-tip to the aluminum transefer, and buff it off with some fine emery or scotch brite. Just as long as you get it all off and it hones out ok, you'll be fine. My saws turn upwards of 14,500rpm and have not had a failure yet after the removal of aluminum transfer.