[papamendy]

I have been rebuilding a 1974 9.9 Evinrude. Replaced all the waterpump components....however when I went to replace the waterjacket gasket with the parts I got from the iboats parts section the waterjacket gasket...although similar dd not quite match up. Also most of one side of the old gasket was solid covering much of the water area with a few holes for water to pass through.The new one is wide open on both sides with the center stip intact to allow water to flow over the top to the other side. (please see part #18-2905 in the iboats evinrude parts section to see) This is the only water jacket gasket I can find listed for this year engine.....any ideas other than making my own out of gaskt material. Anyone else have this experience....thanks for your help.

[OptsyEagle]

That gasket will work fine for you. You will probably find that your watercover has only 9 screw holes and that gasket has openings for 10, which will leave a little gasket material sticking out in the lower left side.

I think the problem is that OMC discontinued the cylinder head design for that motor and started using a design for a 1986 or 1987 that was pretty close to the same, for 1974s to 1976s. This change worked fine.

The reason I know this is that I changed my cylinder head on my 1975 9.9Hp Evinrude this year. My cylinder head came with a slightly newly designed water jacket (that takes exactly the gasket you have). The interesting thing was that when I took the old water jacket off, it had your gasket in it as well (I guess the previous owner had the same problem you are having). I always wondered why I had that extra little bit of gasket material hanging out. In any event, it never leaked water and worked just fine. I would have reused this jacket and gasket except the old water cover jacket would not have fit on the new cylinder head design.

So what I am saying then is that these new gaskets will fit the old (yours) design of water cover jackets and the new (mine) design of water cover jackets. The old gaskets (the one you took out) will only work for the old design.

I hope that helps.

[papamendy]

thanks for the input. I see what your saying and would have been able to use the new gasket....except 2 of the holes that were supposed to match were still off enough to where the bolts would not fit....close, but off enough not to work. Found another parts source which listed the part with a correct picture from the service manual. Hope this works out better. If not, gonna get out the gasket material and x-acto knife and just make a new one myself. At 1.27 its not too much of an expense. Thanks again for the info.

[OptsyEagle]

Or the other option is to ask your dealer for the correct gasket. Yours is OMC#318917 or Sierra 18-0397. They should have it. I know mine had it a few months ago, because I needed the new design (like yours) and they kept trying to give me the one you want now. It took a while to figure out the problem and get the correct gasket.

But like you said they both were less than 2 bucks.