1974-inner water jacket cover/rebuild ?

[country boy]

I am in the process of rebuilding a 1974 mercury 1150, in reading the manual it says to only remove the inner water jacket when necessary .the #4 & #5 has scoring and needs to be honed so after i pull the crank i am taking it to the shop to have it done.would it be advisable to remove it or not my fear is to break off more bolts. i broke only 2 on the outer cover and i have 2 cranks with some good pistons off a 1986 model 115 should i replace just the pistons or replace the connecting rods also. inputwould be greatly appreciated.thanks.

 

[Chris1956]

Re: 1974-inner water jacket cover/rebuild ?

The water jacket cover may stay on when you get the block bored. Sometimes, the borer wil want you to remove the cover over the head, but you might ask him to be sure.

 

[country boy]

Re: 1974-inner water jacket cover/rebuild ?

Here is a pic of what i am looking at.

 

[arsenalpsu]

Re: 1974-inner water jacket cover/rebuild ?

There is no need to remove it and you WILL break some bolts if you do. Those were installed with epoxy resin at the factory. That should only be removed if you were getting water in the cylinders (you would know because the piston top would be very clean, steamed clean) ....actually I wouldn't have removed any of the exhaust covers unless you were getting water in, no need to remove any of them. Be very careful when installing the new inner exhaust cover, if she leaks your in for another rebuild. (if left unchecked)

 

[country boy]

Re: 1974-inner water jacket cover/rebuild ?

There is no need to remove it and you WILL break some bolts if you do. Those were installed with epoxy resin at the factory. That should only be removed if you were getting water in the cylinders (you would know because the piston top would be very clean, steamed clean) ....actually I wouldn't have removed any of the exhaust covers unless you were getting water in, no need to remove any of them. Be very careful when installing the new inner exhaust cover, if she leaks your in for another rebuild. (if left unchecked)

Thanks for the reply,That is what prompted the rebuild i was suspicious of water geting on the # 3 cylinder .it was missing so when i would pull the plug it was orangish looking after a while looked like it was rust forming.so when i pulled the outer cover i noticed the scoring on the #3 ,sorry in first post it not #4 and for not mentioning that.

 

[daveswaves]

Re: 1974-inner water jacket cover/rebuild ?

Thanks for the reply,That is what prompted the rebuild i was suspicious of water geting on the # 3 cylinder .it was missing so when i would pull the plug it was orangish looking after a while looked like it was rust forming.so when i pulled the outer cover i noticed the scoring on the #3 ,sorry in first post it not #4 and for not mentioning that.

While it is possible for water to get into number 3, I doubt that was the cause of your problem. Judging by the baked oil crud it is likely that you were running too hot, probably water pump...and your middle carb leaned out and cooked number 3. Check for dirt in the carbs, remove the filter screen behind the fuel inlet fitting on all carbs. Replace your water pump, check condition of the transfer tube from the pump housing to the copper pipe. I would also rebuild the fuel pump. You are going to have some $$ in the rebuild, make sure you find out WHY.
Not discounting the water possibility, but the odds are low.

 

[arsenalpsu]

Re: 1974-inner water jacket cover/rebuild ?

Dave,

Do you know what year Merc stopped putting those little screens in? Or what year was that service bulletin? I've heard you talk about it a few times, I would assume if they issued a bulletin they would stop installing them as well. Thanks.

 

[daveswaves]

Re: 1974-inner water jacket cover/rebuild ?

Dave,

Do you know what year Merc stopped putting those little screens in? Or what year was that service bulletin? I've heard you talk about it a few times, I would assume if they issued a bulletin they would stop installing them as well. Thanks.

Sorry, I don,t know the exact year, any engine from the 70's is apt to still have them in. I always recommend folks check when #3 melts down as in this case for a few reasons.
1. they might still be there
2. It forces people to remove the carb and clean and rebuild it
3. You have to do a link and sync when you put it back together and that is always a good idea.
Fuel starvation is always deadly on these engines.

 

[country boy]

Re: 1974-inner water jacket cover/rebuild ?

While it is possible for water to get into number 3, I doubt that was the cause of your problem. Judging by the baked oil crud it is likely that you were running too hot, probably water pump...and your middle carb leaned out and cooked number 3. Check for dirt in the carbs, remove the filter screen behind the fuel inlet fitting on all carbs. Replace your water pump, check condition of the transfer tube from the pump housing to the copper pipe. I would also rebuild the fuel pump. You are going to have some $$ in the rebuild, make sure you find out WHY.
Not discounting the water possibility, but the odds are low.

I have rebuilt the carbs already,that you mention it the middle was out of adjustment the spring was up too far i pushed it down and reset to specs on all, would the spring pop back up or should i change this float .this i think may have scored the cylinder.dont you think thanks,

 

[daveswaves]

Re: 1974-inner water jacket cover/rebuild ?

I have rebuilt the carbs already,that you mention it the middle was out of adjustment the spring was up too far i pushed it down and reset to specs on all, would the spring pop back up or should i change this float .this i think may have scored the cylinder.dont you think thanks,

Certainly low fuel on the middle carb can lead to melt down on number 3. It is not likely the spring would pop up again as it is always under load when fuel is in the bowl.

 

[country boy]

Re: 1974-inner water jacket cover/rebuild ?

Thanks for all the help thanks to you all helped me figure out what happend and which way to go with this issue.These mercs are one of a kind to work on and without help would be disasterous!

 

[country boy]

Re: 1974-inner water jacket cover/rebuild ?

Does anyone have any input on this.in looking at the front cover there is a peice that was broke at the bottom where the main water supply comes in and goes to the waterjackets.does it make a differance on the circulation .my best guess is that is what caused the power head to over heat or to run hot when running at high RPM(i was wondering why it had such a strong stream coming out for a motor that was sitting up for some time) Daveswaves looks like you were right on the money with the feul with the float out of adjustment and overheating to melt down the #3 cylinder.my question would be does anyone have an idea or can something be done to repair this or am i stuck with an anchor.

 

[country boy]

Re: 1974-inner water jacket cover/rebuild ?

Does anyone have any input on this.in looking at the front cover there is a peice that was broke at the bottom where the main water supply comes in and goes to the waterjackets.does it make a differance on the circulation .my best guess is that is what caused the power head to over heat or to run hot when running at high RPM(i was wondering why it had such a strong stream coming out for a motor that was sitting up for some time) Daveswaves looks like you were right on the money with the feul with the float out of adjustment and overheating to melt down the #3 cylinder.my question would be does anyone have an idea or can something be done to repair this or am i stuck with an anchor.

sorry forgot to put pics! Well this is the result of having it welded looks like we put some bubble gum on it it looks like it stuck pretty good what you all think it'll make it

 

[daveswaves]

Re: 1974-inner water jacket cover/rebuild ?

I see the chunk that is missing. You can try and find a good aluminum welder who can weld cast aluminum. Otherwise you would be further ahead finding another block. Not that difficult to find.

 

[country boy]

Re: 1974-inner water jacket cover/rebuild ?

sorry forgot to put pics! Well this is the result of having it welded looks like we put some bubble gum on it it looks like it stuck pretty good what you all think it'll make it

This is before and afeter shots.******Bump for response****** Any input/opinion would be appreciated .

 

[country boy]

Re: 1974-inner water jacket cover/rebuild ?

This is before and afeter shots.******Bump for response****** Any input/opinion would be appreciated .Thanks c.b.

 

[daveswaves]

Re: 1974-inner water jacket cover/rebuild ?

Looks like you found a welder that can weld cast aluminum. I don,t see any problem with the repair.