Advice Wanted

[mercurymang]

I recently posted a thread regarding a boat and motor i recently purchased. I had seen steam and was concerned that there may be an issue.

http://forums.iboats.com/showthread.php?t=583370

I decided to tackle the problem and after some hesitation began removing the bolts to get the exhaust cover off. All things considered, it went pretty well. I got the cover off and found the problem to be the thermostat diaphragm. There were a total of 18 or 19 bolts and I got all but 3 out cleanly. The remaining three were the most interior close to the water jacket and i ended up snapping the heads of them. They have about 3/8 to 1/2 inch of bolt sticking out and thought for sure I could get them out with some heat and vice grips but have not been able to get them to budge.
I decided to drill and tap the worst one and was for the most part successful but I did booger up the threads a bit trying to extract the old stainless remnants from the aluminum.
So my question is this. Should I go ahead and do the same for the other two and go back in with helicoils or should i pull the powerhead and take it to a machinist who can do it some justice.
Am i right in being so concerned over these three bolts or is this not that big of a deal?

Here is a pic of the three bolts. You can see them running vertically in the center.

 

[CharlieB]

Re: Advice Wanted

Give each a sharp rap with a small ball-peen, then soak with PB Blaster. Repeat daily.

Get a pair of 4 inch Vise-Grip pliers. And a whole lot of patience.

After a few days of raps and soakings, grab onto one and give it a wiggle. Do NOT attempt to force it to turn more than just a few degrees or you will break it off again. Gently turn it out and in just those few degrees until the corrosion slowly begins to break loose, each time it should turn a little bit farther until it finally feels loose enough to back all the way out.

 

[Maxz695]

Re: Advice Wanted

I totally agree with soaking them over a period of time with PB Blaster!!!! Same for the shock treatment, but.
consider also if the bolt appears to lossen even a touch. turn it back in to a tightening position that will affect the corrosion disipating it to dust and make it not as binding on the bolt and repeat with just a touch over and over again In and then out a touch in then out you get the drift. DO NOT TRY TO REMOVE THE BOLT EVEN IF YOU THINK IT WILL BE OK AS THE CORROSION AND THE BINDING WILL AFFECT THE THREADS> Repeat lubrication constantly during this process.

 

[mercurymang]

Re: Advice Wanted

Will liquid wrench work as well as pb blaster? FYI, these bolts are baaaddd. You still think I can get them?

Edit: I have been fighting these things for days now. I cant get a pair of vise grips that will hold on them. I bought a large pair of channel locks. Still couldn't get ahold of them. I bought a tool at sears that is supposed to hammer on the stud and allow you to get a wrench on it. That didn't work. If you guys say try it again, I will try it again but I'm so ready to drill these guys out i cant stand it.

 

[Maxz695]

Re: Advice Wanted

If you do not be patient and let the lube help then you are doomed before you start. This part of the engine must be 100% in top condition or get another block. Haste makes waste and thats where your heading. let the oil penitrate and do it,s job. If it doesn,t work then get a master to get the job done. 1 Mistake and it,s all over but the crying

 

[mercurymang]

Re: Advice Wanted

So if worse comes to worse and cant get the bolts out, a helicoil wont work in your opinion?

 

[Maxz695]

Re: Advice Wanted

It will but if you can do a great job of drilling and tapping it I,m all for it But remember the studs are alot stronger than the aluminum. If you lose center of the bolt the block cannot be corrected but still may be usable depending. If your confident you have a steady hold down on the block and a drill press to guide the bit then go for it if you must. Try to use all available techniques first as I would hate a good motor go to the Junk Yard for a lack of patience. If this is nessecary then under drill the bolt to make it thin and use a reverse drill bit you can get at any harbor freight and either the bolt while drilling (heat) may come out or can be removed with and easy out and soaking process before attempting to bore and rethread it. Once drilled through the bolt penetrating oil will get to the inner part of the bolt and work it,s way from inside out. This is the best last resort option I can give before attempting re taping (EDIT) Because of the thickness of the original aluminum between the thread and either the water port or the exhaust port is thin as it is putting a helicoil in will make future corrosions and the integrity of the surfaces that much thiner the chances of future in or extrusion become 10X likely. My 70 HP has the exact same configuration and I had a hell of a time getting it to seal even though all my bolts came out. Please for the engine and your peace of mind out there on the water do it right(Edit) I can see where the ehxaust was leaking into the water port and possibly causing you and over heating issue. I woulod never recommend this to anyone nor am i recommending it to you. My surfaces where a bit uneven and I,m pretty handy with a file. well I took a file to mine just enough to see a full clean surface to seal against. I got tiered of buying gaskets X 3 at $15 a piece just for the inner baffle gasket. A bridgeport would be the correct facing machine for the job but I don,t own a machine shop (edit) If you are as crazy as me you must understand this " You cannot just flie the bad sector but the entire surface to match in order to seal properly against the divider plate!" I also did this to my rear cylinder head water jacket area after having it heli weldeded due to massive #3 cylinder corosion around the plug with success

 

[CharlieB]

Re: Advice Wanted

Patience is essential.

You can apply heat directly to the broken stud, then PB to cool it. The penetrant will be drawn down into the corroded threads as the stud cools.

Repeat daily.

One day the stud will turn easily with just a pair of pliers.

How patient are you?

 

[mercurymang]

Re: Advice Wanted

Patience is essential.

You can apply heat directly to the broken stud, then PB to cool it. The penetrant will be drawn down into the corroded threads as the stud cools.

Repeat daily.

One day the stud will turn easily with just a pair of pliers.

How patient are you?

I'm actually a pretty patient guy if I know what to expect. I had wanted to get it on the water this weekend as we are going to have great weather and I've only had it out once since I bought it. Looks like that won't happen though. If it takes more than a few weeks I may pull the power head and take it to a machinist.

 

[mercurymang]

Re: Advice Wanted

I picked up some PB today. Let the soaking begin.

 

[mercurymang]

Re: Advice Wanted

Been a week now. Still hasn't budged one iota. I borrowed an oxy-acetalene setup so I could get some "real" heat on it.

 

[Maxz695]

Re: Advice Wanted

remember after heating tap the bolt to help break down the corrosion away from the threads then hit it with the PB so it will absorb it

 

[mercurymang]

Re: Advice Wanted

I can heat the bolt to glowing red hot and by the time i set the torch down and remove the protective plate, i can almost touch it with my finger. But I've been doing as you suggested for almost a week now. As I have said I am willing to keep doing this as long as necessary as long as you think it will eventually give. I'm just worried that it's so corroded that it wont come out.

 

[Maxz695]

Re: Advice Wanted

Use a smaller drill (Maybe 1/4) bit then the size of the bolt 5/16ths and reem it out (Paying extreem caution not to break the bit in the hole) to spray some lube in there to soak (Essential) but leave enough meat to grab and turn the bolt. This may be the last resort before drilling it and taping it out.Repeat heat tap twist in then out turn in then out keep repeating this motion as the corrosion should break down and disapate). Make sure your as absolutely close to center (use a punch to start the hole and drill all the way through the bolt and there should be some recese bofore hitting the block unless it,s actually that corroded) If you have to resort to retaping you already have a guide hole that will allow a straight cented hole for retaping at the same size bolt. Good luck

 

[mercurymang]

Re: Advice Wanted

Shouldn't i just pop the power head and take it to the machine shop. My attempt to tap the other hole didn't go so well.

 

[Maxz695]

Re: Advice Wanted

that would be best if you can foot the bill

 

[mercurymang]

Re: Advice Wanted

It's only $20 a bolt so money is not the issue. I'm more concerned about screwing something up in the process. Is there anything to be concerned with in regards to removing the power head or is it pretty straight forward?

 

[Maxz695]

Re: Advice Wanted

Take a long nail (3 inch roofing I used cut the tip flat with dykes) after removing the throttle arm and the shifter bracket off and knock the roll pin out of the shifter arm and seperate remove it if possible not doing this will mean lifting the power head as high as the shift shaft over 2 feet and possibly bending the shift shaft. Dropping the LU would be a good idea as well.. The airbox will more than likely ned to come off. It would be easier as well to take off the starter all the electrical to protect it. It makes the engine much lighter to pull off. No need to remove the bolts on the rear that hold the exhaust base plate This will save the gasket, unless you plan to have a look for impellor fins between the block and the exhaust base which while your there might as well check it just to be sure.You can just undo the stud bolts going through the midsection.

 

[mercurymang]

Re: Advice Wanted

My manual specifies that when removing the flywheel, that one should use a crankshaft protector cap. What is this exactly?

 

[carholme]

Re: Advice Wanted

Mercury, Mariner, Honda Flywheel Puller Lifting Ring

The small black ring is a sacrificial ring that fits against the crank inside the puller so that when the bolt is being tightened to pull off the flywheel, no marks or damage is felt by the crank.

Gerry