'72 Merc 500 rebuild candidate or anchor?

[joblo33]

I used this Merc for 15 minutes before it made a horrible sound and siezed up solid. That was about a year ago and at that time I deemed it dead, but with time I started to wonder about it and decided to check it out today. It looks like it is indeed a dud. The other pistons look good and move now, the rod seems to have snapped on this one. What do you think, is the damage too deep for a rebuild? I'm still going to take this apart because I'm curious what caused this.<br />

 

[Clams Canino]

Re: '72 Merc 500 rebuild candidate or anchor?

Check inside to see how bad the bore is. All the parts for that motor are cheaply available.<br /><br />-W

 

[joblo33]

Re: '72 Merc 500 rebuild candidate or anchor?

Any way to get the PH off the casing without a lifting ring? I tried bolting the transom bolts to a stand and pulling the powerhead up with my arms but couldn't make it budge. My other 50's powerhead just lifted off when I unbolted it.<br />Eric

 

[Nos4r2]

Re: '72 Merc 500 rebuild candidate or anchor?

Did you drop the lower unit 1st? That makes it significantly easier.

 

[joblo33]

Re: '72 Merc 500 rebuild candidate or anchor?

yup

 

[joblo33]

Re: '72 Merc 500 rebuild candidate or anchor?

How deep is too deep to be bored? Could I bore it a bit to make it less rough and just live with some huge gashes and low compression or will it self destruct? It was caused by a bearing failure, all the rollers fell into the cylinder and became one with the piston and a couple were stuck in the cylinder wall but I got them out with a toothpick.

 

[ZmOz]

Re: '72 Merc 500 rebuild candidate or anchor?

My 1500 looked like that and still ran fine until the distributor seized.

 

[joblo33]

Re: '72 Merc 500 rebuild candidate or anchor?

Haha, I hope you're not serious, those are chunks of my cam bearing. If you ran it like that I'm amazed the distributor would be the issue.

 

[joblo33]

Re: '72 Merc 500 rebuild candidate or anchor?

That piston is a good paperwieght though. I should put a sign on it saying something like "Have you cleaned your carbs lately"