FAQS on Holt 75 H75 4 Cylinder Gas Engine Model | Stirlingkit

Several days ago I bought a h74 engine but I have a question, which type of oil use it? It is oil for two times engine? I have a doubt because the engine needs an oil example SAE 30. Do you recommend fully synthetic oil for the H74 Twin engine and if so, what grade oil and how much do you place in the crankcase?

answer: Fuel and oil mixture ratio 1/25