Dual Plug Viperhead for YS91... how to shim properly?

[the collective]

I've got a dual plug Viperhead for the YS 91 (bought it used from Sluggo a while back) and I want to install it. I looked at the manual on OMI's website, but I couldn't find any info on the correct shim arrangement to use.

Does anyone know??

[the collective]

never mind... I called OMI and spoke to James about it.

Thanks!

[tnreefguy]

well what did he say?

[DavidH]

James probably told him it depended on the fuel he was using.

Cool Power and Power Master 30% One .004 shim that comes with the head only, Possibly the .008 stock shim only depending on climate.

With Magnum 30% The stock .008 shim that comes with the motor, may also have to add the .004 shim that comes with the head for a total of .012 in shims.

This is what I determined when I was testing the prototype Viperhead for James to go on the YS 91.

The testing was done when the temps were in mid 90's with about 75% humidity.

David

[tnreefguy]

thanks.

[the collective]

Yep, James told me pretty much word for word what DavidH just said.