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Tell me about "OMC Gasket Sealer Compound" (anti-seize properties?)

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pilotart

Regular Contributor
Back in April 1998 I had a severe overheat event, #1 Combustion Chamber had a pinhole corrosion leak into waterjacket and I had to install a New Cylinder Head.

I wrote in the Logbook at that time, that "All bolts torqued with OMC Gasket Sealer Compound". I am positive I used no compound of any kind on the Block, Cylinder Head & Cover or factory (Yamaha 90TR) "self-sealing" gaskets. Just the bolts.

Fast forward 17 years and 200 motor hours and overheat buzzer is back. Lack of frequent use contributing factor no doubt and it's salt water, stored on davits and flushed after use.

After all the usual "overheat" trouble shooting, pulled head and head cover and each and every bolt came out like they were installed yesterday. They were coated with a Maple Syrup colored compound that was still soft and pliable. Head (and Cover) had no corrosion seen this time, but found partial blockage behind head where water exits. (overheat warning only occurred after 'on-plane' speed for five to twenty minutes).

This blockage material that I had mentioned on the 'Overheat Thread' a few days ago has not been dissolved by white vinegar (in a cup) immersion since that post.

Now for the Exhaust Cover removal attempt. I had removed it seventeen years ago to look at that #1 piston and rings and would have reinstalled it using the same OMC Gasket Sealer Compound to seal those bolts. Using this sealer would have been on the advice (at least for head bolts) of my very knowledgeable Marine Maintenance Expert at the time (Tad's Marine). This was prior to the existence of these knowledge sharing forums.

There are eighteen 8 mm bolts exactly the same as the head bolts made from a magnetic stainless alloy, no rust seen on either, just an inch shorter.

Completely unlike the ease of removing those head bolts, these were super stuck and the sealer was not soft and pliable any more. Seven out of the first thirteen snapped off deep inside, just past thread top. Block photo below shows four of those seven are along side exhaust passage but three are perimeter.

So it looks like OMC Gasket Sealer Compound is excellent Head Bolt protection but not at all suitable for exhaust cover.:confused:

The lowermost five bolts would be impossible to drill out without removing Power Head, so I used a 'sawz-all' hacksaw and cut their heads off to have the most shank to work with. Should'a sawed six as one just above cowling edge is too low for drill chuck, so I'll be removing Power Head anyway....

Photos two and three show inner exhaust cover plate, combustion side and water jacket side, four is water jacket side of outer cover. I have done no cleanup of these area's at all and it is obvious now that all would have been well if I'd never removed exhaust cover.

Photo five shows where I've die-cut threads into standing bolt stub and attempted to remove with two nuts (like you would a stud). Used all the heat available from 'MAP' Torch supplemented with an 1100 degree Heat gun and have gotten the stub to rotate less than five degrees in/out with more pressure than two (or three) nuts could apply. Wish I could weld, but that was my poorest skill in Shop Class. Photo six was just before OH buzzer started happening.

Cobalt Drill Bit (7/64th") goes all the way through center of bolts so I can inject Kroil, PB, ATF etc. but looks like I will need 17/64ths to run the 8mm/.125 Tap if I can find where threads start.

Tad retired and Tad's is now "THE BOAT HOUSE" (six locations from Chicago to Naples). They Service (and sell a lot of boats with) Yamaha, but are limited to Evinrude for Re-Power. They also tell me that it's not worthwhile to send block to Machine Shop for re-bore (or bolt extraction) and they just order "rebuilt", but then they're not who wants it to last a long time....;)

I am very tempted by this new 'Two-Stroke' Technology and low-speed Fuel Efficiency, but wish they made less noise. I read the past six months of this Evinrude Forum and found not one complaint mentioned about these latest Evinrude's, not the same over at Honda. I got soured on Automobile Engine's for raw cooled Salt Marine use with my Chevrolet engine'd Mercruiser long ago.

Wish me luck, Art
edit:- photos 2 & 3 are reverse of description and name
Artbehind exhaust cover.jpginner cover exhaust side.jpginner cover water jacket side.JPGinside outer exhaust cover.jpgone (of 12) bolts seized.jpgFew months ago.jpg
 
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This "OMC Gasket Sealer" is still available:
http://www.amazon.com/OMC-Gasket-Sealing-Compound-508235/dp/B004H4HVFC

I have always (before and after the 1998 incident) used either waterproof grease or an appropriate "Never Seize" on Bolts and Nuts with never a problem like this.

The most popular 'Never Seize' is the Copper formula and that would bring galvanic corrosion to any use around Aluminum.

They also sell a Graphite formula which works well, but is messy and your Marine Service Tech will hate that you used it.

Probably the best for exhaust cover bolts would be the "Aluminum" formula version Never Seize.

Hoping for knowledgeable input here before I reach the point (if ever) of reassembly.
Art
 
17 years in salt water use and you expect ANY compound to have prevented thread seizure? Ain't going to happen. Unless you get lucky.
 
Yes, I would expect the proper compound to prevent thread seizure when used correctly. I had even used a 'Tap' to 'chase' the threads before insertion and they were torqued to spec.

Same compound used on the same day prevented thread seizure for the 14 Head Bolts (same 8 mm bolts as the seized) for the same 200 hours of salt water use over the same 17 year period (fresh water rinsed and dry stored between usages). Same result for the 18 Head Cover and 4 Thermostat Cover 6 mm bolts.

Same compound appeared pliable and usable upon removal of every head bolt, whereas it appeared stiff and brittle and to have locked the threads of every side cover bolt. It seems now that this compound is preventing proper penetration of the thread release liquids. I have drilled completely through broken bolt's centers and injected to penetrate from both ends.

All I can take from this was that this recommended OMC compound did a great job for the head bolts, but not for the side cover bolts. Would not expect luck to be so selective. (My favorite definition of "Luck" is "When preparation meets opportunity" :cool:
 
Well you certainly are entitled to your thoughts and opinions. But I am looking at my experience of 24 years in an outboard shop on Florida's Gulf coast. The number of seized/corroded fasteners that I have had to deal with are about uncountable. And I'm talking about motors only a few years old, not 17. In fact, most wind up in the junkyard long before 17 years. And, yes OMC used that gasket sealing compound on the screws at the factory. Does it help? Yes. Does it always prevent corrosion? Absolutely not, as evidenced by your exhaust cover screws. "Luck" probably is modified by specific alloys, and other factors. But stuff still happens.

But I still appreciate you.
 
@fdrgator, thank you for taking your time to provide me information.


I've been on the SW Florida Gulf Coast for 55+ years (after 1st 16 in the Connecticut River Valley) except for a few in New Orleans and then drafted in '65. Retired Pilot now.:cool:


Enjoyed and maintained/repaired at least one boat continuously (three total) for the past 39 years. The most complex outboard repair I've done was the exhaust pipe on my Honda BF-100. I did have the Machine $hop take care of one broken bolt when they did the valves for me.


Had my share (a few) broken bolts to deal with, but until now, never any bolt that I had installed myself, as I always took steps to protect the threads and this was the only time I ever used that OMC seal. It sure worked great on the Head Bolts, but for whatever reason 'bare' would have worked better on those Exhaust Cover Bolts. Exact same alloys, so condition came from something else.


This engine may still very likely be scrapped, but I think it would be best to 'part-it-out' on eBay or CL. The latest Evinrude 90 @ 320 pounds is the most logical re-power option for me. I'm currently at 340 pounds for both my 90 and the 10 Hp 'kicker' and a Yamaha 90 or 115 both tip at 377 dry weight. Hull is rated for 140 but would sink at the stern under those 'marinized' Automotive Four-Strokes that are so popular now.


I've center drilled five of the seven broken bolts so far with 7/64 pilot holes all the way through. One (made in USA) Cobalt bit and lots of 'cutting-oil'. Photo below shows last three done w/8mm nuts over remaining threads to help me 'center' and hold cutting oil.
Three Drilled Bolts.jpg

I do have an Alden "Drill-out" along with a set of left-hand bits, but I think these bolts are stuck far too tight for them. Just ordered two 17/64" (6.7mm) which is correct size for my 8mm-1.25 Tap. This worked best in the past


The five lowest bolts (no drill access) that I sawed the heads off are also a challenge for me. Tried the topmost one with three nuts threaded on and at least :30 minutes heating with my MAP fueled Propane Torch and 1100f Heat Gun. Got it to rock less than 5 degrees and then the three nuts all stripped out, threads (5/16 NC18 Die cut) on stuck bolt shank are still ok.

Have a Great Holiday:)
Art
 
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I wonder if Permatex Aviation Gasket sealer would have done better?? I use it on my engines but I don't run in salt water either. Just a thought.
 
I believe that they are 'equivalent'. The most critical joint would be the crankcase split (a line bored matched pair) where there is no room for any gasket (most aircraft engines split the same) and both my Yamaha Factory SM and Clymer's just say "Film coat...with Gasket Maker or equivalent.".

My Yanmar, Mercruiser and Honda Marine all had water cooled Exhaust Manifolds or Covers and I always used "Gasket Maker" on the gasket surfaces, but coated the bolts and threads with Never Seize and/or waterproof grease (like Corrosion Block's). You must not ever use the popular "Never Seize" formula containing Copper around Aluminum, but this always worked.

Using the 'OMC Gasket Sealer' on the bolts and threads recommendation came from my local Service Marina when they sold me the Yamaha replacement cylinder head and that worked great. (Professional Technicians hate the mess clean-up from "Never-Seize" but they use impact wrenches;)). Coated Cylinder Head Gaskets just need clean, dry perfectly flat surfaces and no sealers at all. SM's make no mention of using any bolt/thread sealers and expect most shops just torque them dry. The leading 'broken bolt' complaint area seems to be Head Bolts and exhaust is right up there as well. Automotive and Motorcycle exhaust deals with much higher temperature's and although shops bolt them dry, if you want to be able to ever remove them again without broken bolts/nuts, "Never-Seize" does the job (I always liked the graphite formula version for that, but copper is fine around steel/cast iron).

I recall seeing reference to reducing dry torque values on greased bolts/nuts, for the precise 'stretch' they need I expect, but not much other mention of thread coatings or sealers. All my SM's for my previous engines went with the engines so no way to reference them now.

There are instances where "Loctite" is recommended to prevent spontaneous bolt/screw loosening and I've used their blue stuff on Dell Computers and never had it cause any 'seizing'.

It seems that the 'take-away' from this experience would be that "Gasket Sealer" on Head Bolts & Threads is OK, but on Exhaust Cover Bolts & Threads it's trouble. (But I can't understand why), there was no excess of it in the blind void behind the six (of thirteen) bolts that did come out, and they did not unbolt easily either. Of the five I hack-sawed the heads off, just two appear really stuck, been working on just one so far.

Perhaps it's somehow that there's greater internal heat where their threads are located (compared to the head bolt's area), below those two plates and two gaskets where water keeps that cover so cool.:cool:
Art
 
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