Hit something under water.... Now something is up!

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,944
About 30 yrs ago my 115 was doing the leak around the spark plug. I had to replace the gasket a few times, first time I used a nonhardening sealer, and guess what it leaked again after a few weeks. I replaced the water jacket cover and gasket again using sealer, leaked again. Third try, new gasket no sealer, and it never leaked again.
 

g0nef1sshn

Lieutenant
Joined
Feb 24, 2015
Messages
1,291
What he ^^^ said....



It's not a head gasket, just a head COVER gasket. There is no seperate head on these engines, it's cast as part of the block... The cover over the top of the block creates the water jacket, what's leaking is the cover gasket. Easy to fix. Just remove all the bolts (there's about 10 of them), pull the cover off, clean it and the block sufaces up and put a new gasket on... Don't over tighten the bolts as that can cause the cover to distort and create a leak. (bolt torque is 100lb-in, about 8lb-ft) I'd use a non-hardening gasket sealer on that one too, to be sure to be sure.... ;)

Chris.......
BTW, be careful removing the cover, they are No Longer Available.... :eek:
Cover gasket number is 27-437772

Have the part number for the bolts? Lookin to get all new ones for when and if i can even get them back in. Looking at pricing all things need now for this project.

Looks like 2 seperate part numbers for the one i will need?
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,944
If you are referring to numbers 9 and 11, #11 are the bolts, #9 is most likely the plug for the hole where you would place a water pressure gauge feed
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Have the part number for the bolts? Lookin to get all new ones for when and if i can even get them back in. Looking at pricing all things need now for this project.

Looks like 2 seperate part numbers for the one i will need?

Merc part number is 10-76630. But I would just go to the local boat hardware shop and buy SS316 1/4"UNC x 1" bolts. You need 10 of them.... 8lb-ft torque.

If you are referring to numbers 9 and 11, #11 are the bolts, #9 is most likely the plug for the hole where you would place a water pressure gauge feed

Correct...
 

g0nef1sshn

Lieutenant
Joined
Feb 24, 2015
Messages
1,291
Picked up some extractors and left handed bits today. Also got 10 SS bolts. I didnt see 316 or unc anywhere on the labels for them. Just 1/4 x 1 inch. Might try getting one out today. Might keep soaking them in some stuff the neighbor brought over for a couple more days. them bottom ones got me worried. Not trying to have to pull the whole motor off!
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
You can't drop the bottom cowl on those engines.... An option (not one I would take) is to drill a small hole in the cowl to get direct access to the broken bolt. At least you could come at it straight. Then use rubber grommets to 'seal' the holes. My solution would be to remove the powerhead, and work on the bolts 'in the open'...

Chris........
 

ajgraz

Lieutenant Commander
Joined
Mar 1, 2010
Messages
1,858
Any of the snapped bolts showing at least some shaft above the block? If so, then maybe try cutting a slot in the end for a big flat blade screwdriver. Then, as has been mentioned, heat with a torch, hit it with some penetrating oil, and pray. If you can try this, then after the heat and penetrating oil, maybe try a small turn in the tightening direction first to see if you can break the threads free.

(If all this fails, at least you're no worse off!)

EDIT: a few more hints: if there are any nicks or corroded areas in the sealing face of either the cover or the block, some JB Weld or Marine-Tex or PC-11 (and sanding) works for filling those. And when I did that gasket on my 1978 70hp, I dressed both sides of the gasket with Permatex aviation make-a-gasket (the brown stuff), and that worked well for me.
 

g0nef1sshn

Lieutenant
Joined
Feb 24, 2015
Messages
1,291
Soooo...... i tried. One. Went good with the drilling and getting the easy out in. Worked slow and didnt use heat. If you read this because you might try it. USE HEAT! Tip of easy out broke in the bolt. I was working as slow as could be. Didnt help. Gonna drop back off at the mechanic who agreed to work on it as a double side/busy job with no rush. More of a busy project for him when he doesnt have anything else to do.

In the mean time ill butter the wife up and look into a weekend job for maybe a new motor. Far shot but if i throw in quitting smoking it may work!. I appreciate all the info in this effort and i would keep going but its time i fold for lack of experience.

Once again.... USE HEAT Lol. Shoulda woulda coulda. But didnt.
 

Pusher

Lieutenant
Joined
Sep 2, 2014
Messages
1,273
Is there enough shank stuckig out for a welder to weld a nut onto the shank? You'd also be heating it up in the process. If so, you might mention it to your mechanic in case his plan involves a method that would kill that option.
 

g0nef1sshn

Lieutenant
Joined
Feb 24, 2015
Messages
1,291
Is there enough shank stuckig out for a welder to weld a nut onto the shank? You'd also be heating it up in the process. If so, you might mention it to your mechanic in case his plan involves a method that would kill that option.

No shank out on any of them. Few threads deep on each.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Sorry to hear that it's all gone pear-shaped.

I know hindsight is a wonderful tool....
For anyone else finding this thread with similar problems, or just trying to remove small SS bolts from aluminium castings, here's how it's done.

First some information regarding the materials you're dealing with.
Stainless steel. Very low shear strength. Breaking bolts off is very easy, easier than mild steel.
Aluminium. low melting point, about 660C (1220F).
Aluminium Oxide. Very high melting point, about 2,000C (4,000F), and forms naturally on the outside of bare aluminium with exposure to air.

When you heat aluminium, the outer oxide layer keeps you from seeing that the aluminium has melted well before the oxide has shown any sign of melting. Once the oxide layer reaches 2,000 degrees and melts, the aluminium below it is already melted and causes the puddle on the floor and a big hole in your casting. So, heating aluminium is fraught with problems. Doesn't mean we can't do it. It just means we need to be careful.

Now, what causes the bolts to seize is the salt interacting with the aluminium and creating that white paste you'll see. It swells up, 'grabs' the bolt and locks it in place.

When confronted with SS bolts in an aluminium casting, always assume it will be seize, and deal with it as such. Put the spanner or socket on the bolt and attempt to turn loosen it. If it goes 'crack' and starts moving without too much force, great, you win. If it feels like it is starting to turn, but you haven't hear that 'crack', STOP, you're shearing it off! The threads are locked and you are screwing the head off. Before you break it a few options are still open. My first method of attack it to try and 'jar' it free. A few solid raps with a hammer and drift, or even the hammer directly on the bolt head. Sometimes that will shake the corrosion products free enough for the bolt to be unscrewed. If that doesn't work, method 2, the 'hot spanner'.... The rule I work to here is 'go in hard, get out fast'. Turn the flame up on the oxy torch and hit the head of the bolt directly. DO NOT heat the aluminium, the heat will conduct down the bolt well enough. Heat the bolt up until it is red hot and glowing nicely. Shouldn't take more than about 20 or 30 seconds. This dries out that white paste holding the bolt in and turns it to a white powder. The loss of the water is what gives the bolt a little extra room to move. Once you have done that, LET IT COOL... While the bolt is still hot, it will shear even quicker. Once it cools, give it a few hits, for good measure ;)... And try and unscrew it again. Again, feel it and listen for the 'crack'...

If a bolt does start turning but 'goes tight' then, and only then, turn it back. If it doesn't move initially, DON'T try and turn it backwards (tighten). All that will do is break it off faster by increasing the shear force at the head/shank junction. (yes, I know some of you have done that and succeeded. You got lucky, or the bolt was mild steel, not stainless.)

When all that fails you may be left with no other option but to shear it off and deal with the broken bolt. If you can, before shearing it off, centre punch and drill the bolt exactly in the centre. It's much easier to get a centre on the head than the broken shank. If the hole is even slightly off centre, the drill will move off and as aluminium is softer than SS, getting it back to centre again is very difficult. Personally, I don't like 'easi-outs', they break off more often than not, and removing a hardened piece of easy-out is beyond most peoples' capacity, mine included. I prefer to drill the bolt to the tapping size and just re-tap the hole with the remnants of the old bolt there. Most of the time, the old bolt will come out when very little of it is left anyway.

I also don't like dealing with stuck bolts in awkward spots, the ones at the bottom of the head cover in this case. I would just pull the powerhead off, put it on a stand on the bench and work with easy access. That would also give the opportunity to do the exhaust cover and powerhead gasket replacements at the same time.

I hope this helps anyone else facing the same problem.

Chris.......
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,047
You heat the aluminum.-----Aluminum expands at twice the rate of steel.----That is how it lets go.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Yep, I knew there'd be one :facepalm:.... You're not trying to expand anything, you're trying to dry our the products of corrosion... Getting the water out is what makes the bolt loose, not 'expanding' anything...
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,047
The aluminum expands at twice the rate of steel.----You heat the aluminum and steel parts loosen up..-----Bearings fall out out of aluminum housings when heated !!!!
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
The aluminum expands at twice the rate of steel.----You heat the aluminum and steel parts loosen up..-----Bearings fall out out of aluminum housings when heated !!!!

Whatever.
 

g0nef1sshn

Lieutenant
Joined
Feb 24, 2015
Messages
1,291
hahhaha, with no where near the experience of racer or achris, I appreciate your write up achris! That was very informative. And racer I see where you are at. And Im sure somewhere in the difference of opinion/experience it will help others research more before going forward. I knew heat could be used. I knew it could not be too much or melted from my googlin and video watching. But I did not read or see the "heat the bolt from the head only" tip. Thats why I went heatless. I did not want to over do it. But... Trial and error is how we learn. And worst case I will get the motor back no worse than it currently is and I will have something to work on again as a project of learning and eventually put some more horse power back on the boat I have had in the water a grand total of 3 times. But I did shoot my first banded duck on the 3rd trip. First hunt from the boat, first duck (from this boat), first band. Still got the kayak! paddle power! no gaskets hahahaha
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,047
Many shops would have or you could make a " dummy cover " from say 3/4" steel plate.---------you would use that as a drilll guide.-------------Drill will not wander to the side with such a jig !!--------Dummy cover could be half the size of the actual cover too.----Co-efficient for expansion of aluminum is around 0.000012" / inch / degree F- and steel is half of that value.---Look it up if you like !
 

Pusher

Lieutenant
Joined
Sep 2, 2014
Messages
1,273
Many shops would have or you could make a " dummy cover " from say 3/4" steel plate.---------you would use that as a drilll guide.-------------Drill will not wander to the side with such a jig !!--------Dummy cover could be half the size of the actual cover too.----Co-efficient for expansion of aluminum is around 0.000012" / inch / degree F- and steel is half of that value.---Look it up if you like !

I like that drill guide idea!!! You would have the other bolts to lock the guide down too... Pretty slick.

Now I'm no genius but I heated my pistol up and iced a sight to get the sight to let go and drift out. How is this different than heating the block and removing the bolt.... Or heating a housing to remove a race?

I'm GUESSING you're both probably right in your own ways but I'm kind of interested in the pros/cons of both perspectives.

Seems kind of similar to how our government works. One party sets things up for eight years then the next changes to the other method and we never get the benefit from either approach :)
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,047
If both materials are the same then they both expand and shrink the same !
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
I like that drill guide idea!!! You would have the other bolts to lock the guide down too... Pretty slick.

Years ago my business partner and I built a set of tools to remove broken bolts from the original stern drive water pocket covers. It also involved a steel copy of the pocket cover, hardened, and a set of long drill extensions. All that was needed was one bolt to come out successfully and the drilling template worked a treat. And that is where we developed the techniques I describe for getting corroded stainless steel bolts out of aluminium housing.

To continue....
The problem of heating the aluminium is that unless you have cleaned all the oxide off before heating (within about 6 hours) then you have NO WAY of telling how far the aluminium below that top layer of oxide has gone. (See the temperatures of melting in my post earlier).
Another issue is that if you try to turn a stainless steel bolt that is still quite hot, it WILL break off. And if you let it cool then you're back to square one, with the aluminium and the steel back at their original sizes
Yet another issue is we are not trying to expand the aluminium, we're trying to get the products of the corrosion process to let the bolt go so it will turn, and getting those products dried out is the key....

Releasing a bearing from a casting it an entirely different job, and for that, yes I definitely heat the housing....

Chris......
 
Top