Lightwin 3hp cyclinder head orientaiton

[OMCJoe]

Quick question. I’m replacing the head gasket on my 1955 Evinrude lightwin 3hp. I noticed the head bolts are symmetrical, but the spark plug is not in the center of the cylinder bore. Is there a specific orientation the cylinder head needs to be oriented? Unfortunately I did not notice this until the head was off the motor. Thanks!

I am thinking the plugs need to be on the opposite side from the exhaust cover, as this is how my Fleetwin has the spark plugs oriented. Is this correct?

[frankr]

Look closely, and you will see a small projection on the top end (or the bottom, I forget which). Anyhoo it matches a projection on the block.

[dave-bernard]

spark plugs are on the starboard side.

[OMCJoe]

Thanks Guys. It’s interesting because I did notice a projection in the casting of the head, but I was not able to find a matching projection in the block. I’ll put them on the starboard side. I assume the basic concept is that the spark plug should be closest to the incoming air fuel charge as it flows into the cylinder….

[frankr]

So I looked it up. Projection boss goes up.

[outbdnut2]

Be sure the head is not warped. That model is known for heads that warp slightly causing the head gasket to blow between the cylinders. Run a straightedge over it to check. If its not flat, lay emery paper, or other suitable metal sanding paper on a known flat hard surface and rub the head on it until it’s sanded flat.
Dave

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cajuncook1

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