Over torqued head bolts?

I changed the head gasket on a 70hp 1990 Evinrude, cleaned everything spotless and applied Permatex Avation liquid to the bolts and installed in sequence and torque specs of Evinrude manual 18-20 ft lbs. I tested the engine in the tank and had a small leak out one of the bolts. I ran the engine for a while but it did not seal that leak. So, I went back and torqued it to 23-24 ft lbs. while it was still hot. The leak was less, but had not stopped, so I turned off the engine and called it a day.

Should I go back and remove the head and put some sealer on the head face where it leaks from ( I think there was a ding there), or apply some JB Weld? Then torque cold to 20lbs.

Should I loosen the bolts now, so the gasket does not get over crushed by the extra lbs of torque? Will the gasket be re-usable at 20lbs?

I was going to just run it as it is to see if it seals with time and heat.

What do you ME experts say?

Just my opinion, but I'd say the gasket is already over crushed by the high torque. Remove the head and deal with the ding, make sure the head surface is flat, and use a new gasket. The gasket probably has pre-applied sealer (??), so don't add anything.

I believe that when you use a thread lubricant, never seize, oil, Permatex Aviation or any other material, you should reduce the torque value by 30%. All the listed torque values are with dry threads. By using anything one the threads your running the risk of over torquing the fasteners.

It was here years ago that the mechanics told me to use Permatex aviation on the head bolts and thermostat bolts to help with aluminum corrosion. Should I reduce the torques down to at least the minimum of 18lbs (or less? 30% off the dry 18-20lbs is 12.6 to 14 lbs! That's not much.), or should I just install without the Permatex and torque to 20lbs?

As I stated, all torque values are set for clean dry fasteners. When you use a lubricant you don't have the friction drag and easily over torque.
I picked this off the net:
-Threads with anti-seize paste added to it has as much higher tension (Up to 71% increase) than with dry threads. That extra tension could conceivably strip out the threads. This could be the reason why spark plug installation specify that a 3/4 turn after seating rather than a torque value.
-When you apply anti-seize to a fastener and torque it to 100in-lbs. The amount of force you put on the bolt is as if you just torqued the bolt to 170 in-lbs!! You are effectively putting too much force on the bolt.
-Base on test results, I would never use anti-seize on cylinder head bolts, or other critical fasteners other than spark plugs. If you have to use it, be sure to reduce the torque. I read from various sources that you should reduce it anywhere from 10% to 60%. I would reduce it by 35%. You would still be putting more tension on the bolt, but should be ok.

I know anti seize is not what your using but this is a good example of how a lubricant changes the torque value.

From the repair manuals I've been reading, the recommendation is to apply the anti-seize on all bolts and torque to spec. Nothing about under-torquing anything. I'm not saying anyone here is wrong, just what the service manuals say. Whatever value you torque to, I'd be sure to use the anti-seize. Well, unless you just like drilling and tapping out bolts whose head has been broken off.

I meant to add... It certainly isn't going to hurt to use gasket sealing compound on both sides of the gasket. It may alleviate your leak, but it surely won't cause any problems.

TipDS said:

From the repair manuals I've been reading, the recommendation is to apply the anti-seize on all bolts and torque to spec. Nothing about under-torquing anything. I'm not saying anyone here is wrong, just what the service manuals say. Whatever value you torque to, I'd be sure to use the anti-seize. Well, unless you just like drilling and tapping out bolts whose head has been broken off.

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Then go by what the manual says.

MY Evinrude manual does not say to use Permatex Aviation or any lubricant on the head bolts, it also does say anything about the torque must be dry.

Klink said:

MY Evinrude manual does not say to use Permatex Aviation or any lubricant on the head bolts, it also does say anything about the torque must be dry.

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I didn't say not to use it, but be aware that torque values are with clean dry threads on fasteners. One of the engine mechanics should chime in here and give you some of their thoughts on this subject.

I'll still use the Permatex Aviation on all my bolts to help with oxidation, but I will use the 30% torque idea, if it is correct, the actual pressure on the heads will be the same anyways. I may use Permatex on the gasket too, depends how the ding repair goes and what the gasket looks like (I got Sierra brand this time). I think a small sliver of gasket smothered in Permatex Aviation is all that is need to fill the ding.