OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions on Other Engines Yamaha MZ175 losing power

As BigTed suggest probably the ignition system. One thing of note here is that there is a low oil sensor involved.

Also there is 5 versions of this engine so complete model would be need for parts look-up.

You can look-up the part via the following link.

Yamaha Small Engine Parts