I'm hoping someone can help with the above outboard model #LD12A ser #j2721168. I removed the t-stat cover to inspect and test the t-stat. it tested good but the inner gasket is toast I cannot find a part # anywhere. the manual I have says it doesn't have one but suggests installing one if operating in water under 50 degrees. I usually run it in water between 45-65 degrees do I even need it or can I run it without one. if I need it where can I find a part # for it.