Brown deposits at cylinder head seam...normal? PIC

[Lowranger]

'89 Johnson 70 w/1600 hours. 70/30 fresh/saltwater use. Always rinsed witin 10 minutes of trailering. I've had this sweetie since she was a foal. There are brown deposits evident all along the cylinder head/powerhead joint and the exhaust cover/powerhead joint.

. I honestly don't know if they've always been there or appeared over time. I mentioned them to an OMC tech up in Olympia and he said it was salt precipitating out through these joints. He recommended that the head/cover be removed, deposits scraped, and surfaces trued(sanded on glass block). My regular tech said it was simply the emergence of adhesive/sealant from the gaskets and was normal and not to worry. However, I'd like the opininions of experienced hands here on the board. BTW, the brown goo visible in the pan is just LPS 3 overspray and is unrelated. Motor still runs like a SUPER seahorse.

 

[rodbolt]

Re: Brown deposits at cylinder head seam...normal? PIC

its pretty normal. its the salt and minerals ozzing out, its also why I like to change the head gasket at 4 or 5 year intravals, change it before it fails and while the bolts still come out .<br /> only problem we had with the lost foam casting block and head was occasinaly the corrosion would push the headgasket a bit and create a combustion gas leak into the cooling system, usually shows up as a hot horn above about 3800.

 

[Lowranger]

Re: Brown deposits at cylinder head seam...normal? PIC

Thank you for your quick reply.

I like to change the head gasket at 4 or 5 year intravals, change it before it fails and while the bolts still come out .<br />

That's just what the Olympia tech said. OK, I'm convinced it must be done. However, I'm concerned about removing all those bolts intact. Must be 30 or more between the head and exhaust cover. I have the factory OMC service manual to guide me and a can of PB Blaster. Is there anything I can do to help ensure that all those bolts (16 1/2 years untouched) will come out in one piece? Also, I assume that truing the surfaces involves a figure-eight pattern. Recommended grit? Wet or dry? Finally, neither gasket is available over in I.B. parts country. I WAS able to find a head gasket at another site but no sign of one for the exhaust cover. Are they still produced?

 

[andy6374]

Re: Brown deposits at cylinder head seam...normal? PIC

I'm sure you can still get the head gaskets. Head gaskets are usually, as far as I know, installed dry. Don't know the grit, I'm sure rodbolt will.<br /><br />PB Blaster is good. Let it soak for awhile, maybe keep spraying everyday for a couple of days before the project. However, heat is the obvious choice for getting out those stubborn bolts. A MAPP torch is about as hot as you can get without melting the block. Even if you break off some of the heads of the bolts (which you probably will), once the exhaust and head covers are off there should be enough of a stub of the broken bolt to grap with some vice grips and turn out.<br /><br />-Good luck<br />andy

 

[MCM]

Re: Brown deposits at cylinder head seam...normal? PIC

Try Outboardparts.com for the gaskets etc.<br /><br />Good Luck

 

[rodbolt]

Re: Brown deposits at cylinder head seam...normal? PIC

I like the BRP gaskets myself and wont even open the package on sierra ones.<br /> I also coat both sides of the gasket with BRP gasket maker or quicksilver perfect seal.<br /> I use a 6" wide belt sander with 120 grit to surface them if I am taking less than .010" or so. the object is to remove as little materiel as possible yet make the surface true.<br /> I have done it with a medium mill ******* file a sheet of 120 and a glass plate.

 

[andy6374]

Re: Brown deposits at cylinder head seam...normal? PIC

rodbolt, where can you still get quicksilver perfect seal?

 

[Lowranger]

Re: Brown deposits at cylinder head seam...normal? PIC

Thanks for the feedback guys, It looks like the only way to get the exhaust gasket may be to buy an entire gasket set. About $35.00 online. I strongly suspect that these are Sierra parts. I'd lke to stick with factory stuff if possible. I guess I'll check with my local dealer. I'll report back.