evinrude overhaul, shows pits in head

[inohv8]

I got hold of a 74 rude 70 hp.. for a winter project..(something to do..), I was told it needed a new piston.. well, after pulling the head off, I noticed what looked like something fell in and dinged the piston, no problem, but the head itself is concerning.. although it is not cracked, the top cyl. looks fine but the head has some small pit holes in it.. should I be concerned about hot spots? it does not look like it is burnt, but not sure what caused it, bad casting? or no concern needed..feedback appreciated.. (no replacements on ebay yet)

 

[DJ]

Re: evinrude overhaul, shows pits in head

The head has to be smooth. You are correct to be concerned about hot spots.<br /><br />I would be willing to bet there is some piston damage.

 

[inohv8]

Re: evinrude overhaul, shows pits in head

Actually that piston looks good, that is what got me confused..(top), the mid piston is the one that had something fall in..

 

[Bradster941]

Re: evinrude overhaul, shows pits in head

Can you post a picture or two?

 

[inohv8]

Re: evinrude overhaul, shows pits in head

is there a place you would like me to post them to? I would be glad to...<br />Stan

 

[inohv8]

Re: evinrude overhaul, shows pits in head

I think i have a place. will post tomorrow..

 

[DJ]

Re: evinrude overhaul, shows pits in head

The middle cylinder gets the hottest in those "loopers".<br /><br />There were some cooling system service bulletins out on those. <br /><br />If you replace the water pump, make sure you get a complete OMC kit.

 

[inohv8]

Re: evinrude overhaul, shows pits in head

I have posted 4 pics in one.. the cyl head pic is beside the piston pic for the corresponding piston.. please select the jpg. labeled head,<br />www3.sympatico.ca/stanw

 

[Dhadley]

Re: evinrude overhaul, shows pits in head

Good pics. Looks like a ring broke. After you get it apart we'll know for sure. A good used head is probably easy to find.<br /><br />Good luck!

 

[inohv8]

Re: evinrude overhaul, shows pits in head

Thanks for the info.<br />I went to Litner and Bush (engine machine specialists), they suggested to buff out the burrs to avoid pre-igniton, and that the pit holes are small and should'nt cause a problem if another head can't be found.

 

[Dhadley]

Re: evinrude overhaul, shows pits in head

You'll want another head.

 

[DJ]

Re: evinrude overhaul, shows pits in head

These guys will probably have a head.<br /><br /><br />www.twincityoutboard.com

 

[GatorMike]

Re: evinrude overhaul, shows pits in head

Be careful and check that used head over real close. I drove 40 miles to Merrit Island to pick one up last week for my rebuild and when I got it home I found it had a broken bolt in it. Took me 2 1/2 hours and about 20 bucks in bits and easy outs to get it out. That outboard scrapyard will have an irate customer in their office the next time I am in the area.