Cracked block - take off the carb?

[goaskbudge]

I was told by my a dealer that I have a crack in the block of my 1973 Mercury 402 (water was coming out of the top spark plug hole). I pulled the powerhead and can see quite a bit of the block just by taking off the back block cover & exhaust cover. I haven't yet seen the crack. Where do cracks on 2 cyl. generally occur and is it possible to find them w/out pulling the carb? Thanks.

 

[hondon]

Re: Cracked block - take off the carb?

You're seeing about as much of the water cooled side of that engine as you can see .There is no cooling going on in the intake half of that case.What are you trying to accomplish?If you did,nt trust the diagnosis,why did'nt you get a second opinion?

 

[goaskbudge]

Re: Cracked block - take off the carb?

Thanks a lot for the info. I was hoping that, if it was somewhere that I could get to it, I could repair the crack w/ JB Weld rather than install a new block. Is there a way you recommend checking for a crack if you can't see it?

 

[goaskbudge]

Re: Cracked block - take off the carb?

Ok, I've taken out the driveshaft and separated the block. Everything looks great. What does a cracked block look like? Is it obvious? Thanks.

 

[WillyBWright]

Re: Cracked block - take off the carb?

You were misled. Water coming out of the sparkplug hole is almost certainly not caused by a crack. It is caused by overheating which could cause a crack. The cover just warps a bit. A new gasket usually takes care of that. If you're not finding one, you probably don't have one. If there is one, it can't be fixed. Epoxies won't last long and welding just makes it worse.<br /><br />As long as you're in there, hone the cylinders and re-ring it. A new reed block would also be very advisable. New crank seals. But if you weren't getting water on a sparkplug after it ran for awhile, you probably did a whole lot of work that was unnecessary.

 

[goaskbudge]

Re: Cracked block - take off the carb?

Much appreciated. I'm starting to put it together today (w/ honed cylinders and new rings) and we'll see. If nothing else I've got the experience of breaking one down under my belt. Thanks!