1980 115HP 2 stroke inline 6 rebuild question's

[Mr old merc]

Hi all,
I am in the process of a complete rebuild of a 1980 115hp Tower of power. I'm doing the bottom, middle and full power-head rebuild.
I melted a piston which I understand is fairly popular with these old girls.
My questions are;
1/ Has anyone got the torque settings for all the bolts on the power-head? Or anywhere else for this matter.
2/ Has anyone replaced all the bolts for Stainless steel? I have got out every original bolt - bar one. They are in fair condition and I know these bolts are very good quality but time takes it toll, and Stainless steel is fairly cheap now days.
I am concerned about galvanic reaction. I would also like to put some copper grease or similar on the threads, but am concerned that I will have incorrect torque settings if I do this. Not sure how these old girls are affected by incorrect torque settings.
3/ Does anyone know what I can get a liter of Mercury Charcoal black paint from (In Australia preferably)? I have a compressor & gun.
4/ Does anyone know if someone does the decals for this era?
Any help appreciated.

 

[Faztbullet]

When you say complete rebuild are you boring it????

 

[Mr old merc]

No. not re-boring. It doesn't need it. It all has consistently good compression. Except the knackered one. The melted piston is the only one that's not original. It looks to be 30 thou over.
Plan is to replace this one only with another 30 thou over.
The rest leave as is.
I would like to do all but I don't think the $'s would be worth it.

 

[Scott Danforth]

Hi all,
I am in the process of a complete rebuild of a 1980 115hp Tower of power. I'm doing the bottom, middle and full power-head rebuild.
I melted a piston which I understand is fairly popular with these old girls.
My questions are;
1/ Has anyone got the torque settings for all the bolts on the power-head? Or anywhere else for this matter.
2/ Has anyone replaced all the bolts for Stainless steel? I have got out every original bolt - bar one. They are in fair condition and I know these bolts are very good quality but time takes it toll, and Stainless steel is fairly cheap now days.
I am concerned about galvanic reaction. I would also like to put some copper grease or similar on the threads, but am concerned that I will have incorrect torque settings if I do this. Not sure how these old girls are affected by incorrect torque settings.
3/ Does anyone know what I can get a liter of Mercury Charcoal black paint from (In Australia preferably)? I have a compressor & gun.
4/ Does anyone know if someone does the decals for this era?
Any help appreciated.

stainless bolts are usually not strong enough for critical joints like crank cases, heads, etc. especially the 18-8 crap you get at your local hardware store.

NEVER, AND I REPEAT NEVER put copper grease on a bolt going into aluminum. you create a galvanic reaction that will lock the bolt in place within a few weeks. copper and aluminum together is a duracell battery that you can almost power the dash lights off of. Anti-sieze in a marine environment is also a no-no. it will become always-sieze. if your concerned about corrosion, get permatex #3 and coat the threads. 30 years from now the bolts will still back out. do not use tefgel on the bolt either. you will never get it to torque up and the bolts will most likely fall out.

Mercury Black is PPG 9000 black or 9300 black. same a any GM "tuxedo black"
here is an exerpt from a manual

ebay has decals

 

[Mr old merc]

Thanks for the sound advice Scott.
I have now given all the bolts a bath of vinegar and wire brushed the threads. They are all in good nick, so back in they go.
I will source the paint as you mention above. Thanks again.
The decals on Ebay are not the same ones as my originals. Very different.
The ones i have are seen in;

https://www.google.com.au/search?q=...UICigB&biw=1920&bih=987#imgrc=9HgVavkC0krLWM:

Ill have a closer look at the US ebay site to see if they are on there.
Just looking for the torque settings now.

Cheers

 

[Mr old merc]

Found the decals in Canada on Ebay. Slowly getting there.

 

[Chris1956]

Remember something caused the piston meltdown. It is usually overheat, clogged carb, incorrect timing or lack of fuel. So, along with the rebuild you need to rebuild the carbs, fuel pump, waterpump and do a link and synch, to stop it from melting the new piston. Clean the dist cap, and check the spark plug wires for arcing to ground and resistance. Restance should be zero. Rotor is not removeable and fragile and expensive.

New pistons will likely have two keystone rings, versus the 3 rectangular rings of the original. You can get new rectangular rings for the original pistons, but they may not help much, if the compression on the 5 good cylinders is still good.

It makes sense to inspect/replace the top and bottom main bearings, and replace the lower crank seals. As was stated, the original bolts were grade 5 or 7. SS bolts are usually grade 2, and not strong enough. Torguing the crankcase bolts is done from the center of the crankcase outward, alternating top to bottom. I do not remember the torque value, sorry.

 

[racerone]

Distributor cap ?

 

[Scott Danforth]

which piston melted? if its one of the top ones, I would be looking at a lean condition with the top carb

 

[Faztbullet]

Need to "mike" the cylinders as I can count on1 hand all the TOP motors that didn't have worn cylinders.....

 

[Mr old merc]

All,
I do plan to rebuild the carbs, fuel pump and water pump. Ill have to do a bit of research on the 'link and synch' though as I don't know how to do this yet.
The history is the engine had a piston replaced (3rd piston from the top) about 15 years ago. I don't know why. It has 2 rings whereas the rest have the original 3.
This is the piston that has now gone again.
Plan to replace all the bearings and seals that I can still get.
I hear bigger jets will cool the motor down somewhat. Not sure what size are in at the moment but will check when I get to the carbs.
There is no dizzy on this old girl. I think it is actually 1982 motor. S#6094045.
If I could get a sleeve, I would redo the knackered piston cylinder in original size and put an original piston back in, but alas, they don't seem to exist.
I cant recall the compression figures but they were all consistent. Maybe all consistently bad? Without the book, i am a bit blind to the specs, however it was pretty good from memory. Far too many beers between then and now.
Should I get a new Merc srew for the one I snapped or aftermarket? I'm inclined to keep the Merc type. Its a good reflection on the quality of materials that were used for a motor that's over 30 years old I think,

 

[roscoe]

Yes, a 1982 motor.







https://garzonstudio.com/outboard/mercury/mercury-1980-1982-115-hp-decal-set.html

 

[Mr old merc]

Thanks guys.
The festive season slowed me down a little but now ready to put her all back together.
I have bored my melted piston cylinder out and now got all the parts. It was a 20 thou over. Now bored out to 30thou.
The piston is two keystone types.
Can you let me know which way the chamfer goes?
I would prefer to torque all bolts as they are done consistently for a good reason.
I have put a tap & die set through every bot hole and every bolt. So now they are all clean. I will use a bit of Permtex #3 on the threads so may reduce the torques somewhat if they are supposed to be done dry (Which I presume they would have been).
Now I am only stuck for the torque settings.
Off to the local library to see if manual is there.
Cheers again all for the comments.

 

[racerone]

Chamfer ??----I think you need to take a close look at the ring grooves.---Rings will only go one way !

 

[sms2112]

https://www.youtube.com/watch?v=eSk01fvCbec&t=308s . Link and synch vid