Lower unit bolts

[andy6374]

87' 60hp <br /><br />Propane or MAPP torch? How long can each be used safely? As I posted previously I broke 1 out of the 5 tstat housing bolts and would like to break none, if possible, of the lower unit bolts. I tried them today and I know they are eager to break or more specific they are really tight and I didn't force em' at all. <br /><br />It must have been many years since the tstat housing was removed based on the saltiness of the bolts, housing, and salt within the block/head-cover. So I imagine the same holds true for the L/U.<br /><br />Thanks

 

[surlyjoe]

Re: Lower unit bolts

mapp gas is hotter, maybe hot enough to melt aluminum, just be careful you dont hold it in one spot too long. heat it up and cool it back off with the penetrating oil of some deisel fuel a few times and they should come out. do yu have an impact driver?

 

[andy6374]

Re: Lower unit bolts

thanks scrumbler-<br />Nope, but if I did I don't think there is enough room to fit a drill inbetween the anti-cav. plate and the bolts. If there is room, I can get my hand on one.<br /><br />Anyone know if MAPP is hot enough to melt the alum.

 

[rodbolt]

Re: Lower unit bolts

beats me I only use oxy/acetylene. its the only way. sometimes ill get it hot and keep it that way so the bolt will bring the threads out with it. its easier to repair if the bolt does not have to be drilled.<br /> you would be amazed how much heat it takes to melt a housing. its possible to bubble it a bit but a meltdown is unlikly. dont use any oils with heat. it will burn.<br /> once you get it hot keep it hot until the fastener is out or the aluminium will shrink and wedge the fastener tighter.<br /> the fastener wont shrink as fast as the hole nor will it expand as fast. a neat trick is to submerge the unit for 24 hours and when you start heating it the moisture will help boil the corrosion out.<br />if ya dont believe me try cutting a hole in a mid section with an oxy/acetylyne rig.

 

[R.Johnson]

Re: Lower unit bolts

rodbolt: I seen that oyx/acetylene coming before I even read your post. I'm glad I don't have to deal with that on a daily basis.

 

[andy6374]

Re: Lower unit bolts

rodbolt-<br />If the MAPP or Propane torch doesn't work, I guess I will have no choice but to try oxy/acetylene. In regards to the oxy/acetylene, how long do you usually heat the bolt. What much does a oxy setup cost?

 

[MCM]

Re: Lower unit bolts

Andy, It would probably be more cost effective to rent one for a day or so. Also you should get instructions on how to use one as well. <br /><br />Oxy/acetylene is typically used for cutting through metal not heating it.<br /><br />Also pure Oxygen and oil don't mix well, it can be an explosive combination if you're not carefull.

 

[R.Johnson]

Re: Lower unit bolts

MCM: Your age is showing! They have been welding with oxy/acetylene for a long, long time.

 

[MCM]

Re: Lower unit bolts

It's true, how nice of you to notice. I'm just saying it's not something to try without knowing what you're doing.<br /><br />By the way I'm a whopping 47

 

[Paul Moir]

Re: Lower unit bolts

You can melt small aluminium parts with MAPP, like if you really went after a thermostat cover sitting all by itself. But a lower unit? I really doubt it would even be possible.

 

[andy6374]

Re: Lower unit bolts

Thanks for all the advice guys. As I plan on having to use the torch more than once I will just buy one. I think I am going to start with a MAPP torch first and in time, as I get more comfortable and as needed, I will try an oxy torch. <br /><br />I am also going to be pull the cylinder heads on my black max to change out the head gaskets, so the torch will come in handy then as well. But this won't be nearly as bad because they were replaced 3 years ago.<br /><br />Thanks again.