Does anyone know the size of the 4 internal O-rings in these motors? There are 2 on the crank and 2 for the water. Thank You!

The ones on the crank are 2mm cross section thickness and 17mm I.D.

The water ones I can't tell you as I don't have any or a engine case opened up at the moment.
Measure the two depths of the recesses and add 1mm for the crush to get the thickness of the oring cross section.

Then take that number X two and subtract that number from the O.D. of the recess and that will give you the I.D.

I want to say those should also be 2mm cross section. The diameter guessing 9-10mm but you will have to measure those recesses.

Thanks Daniel.

I never cut the o ring in two pieces like they come with the splits at the case split. I make only one cut and I put it 90° from the crankcase split.

Don,
Good chatting with you yesterday.

Here is J & G Jacks contact info if you are interested in getting the rings told you about I know he stocks.

They are the top oring on the head button around the sparkplug on the 36mm engine. Actually the 34mm is probably the same.

jg-motors.com/Page_8.html

Daniel, Always a pleasure! Thanks for the info. Don.

They are "- 018" at any seal/o-ring supplier. 7/8 x 3/4 x 1/16"

Thank you .