Heat plate / Water seperator plate

I am looking at buying what I believe is a 1982 Mercury 18hp outboard. The seller is getting rid of it because his local shop told him that "the heat plate/water seperator plate??? was gone and they don't make the part anymore" This sounds like a load of bunk to me but I thought I would check around. My questions are

What is a heat plate / water seperator plate?
Is it true that I can no longer source this part?
If I can get one what is it worth?

The more feedback the better thanks everyone

Re: Heat plate / Water seperator plate

If its the exhaust plate I have never seen one bad, if it was used in salt or brackish water its possible its bad. The plate is NLA fromMerc but you should be able to find one one Ebay or pm me as I may have one in trailer. Be careful as if engine got hot it may be worthless as its a chrome bore block, this means if any cylinder damage it will need to be (A) resleeved or (B) new block.

Re: Heat plate / Water seperator plate

I have been poking around online and I am finding my minimal knowledge a burden. I have found references to two things that might be what the seller is talking about but I can't be sure.

One is the heat transfer plate. I am guessing this is the exhaust plate you are talking about and based on the name of it I am guessing that it cools the engine somehow buy cooling the exhaust? am I close?

The other was a water fuel separator which I have no idea what it does but I only found it in reference to much larger motors in the 115hp range.

I am serriously considering buying this motor and I just want to make sure I don't get in over my head.

Am I on the right track? If it is the exhaust plate what would that cost to replace?

Re: Heat plate / Water seperator plate

If it does'nt run keep shoping