- Joined
- Nov 29, 2009
- Messages
- 7,293
I bought a generator with a Honda gx390 engine on it and I noticed that Honda makes their own oil. I think it's called GN4 10w30 and it's SJ rated. This engine does have a flat tappet tappet valve train.I was thinking about getting some and using that for the first few changes and then switch over to the amsoil ASE small engine oil after the engine has around 100 hours or so. Can you run regular SM rated oil in this engine? The compression ratio is 8.5:1 This engine is expensive so I don't want to take any chances.