Totally don't understand what I can't find something that simple as a diode. Should be a custom marking, never see this. Even if it is UPM and not UMP, no luck.
We need to find a a diagram and estimate requirements of the diode, so you can replace it.
Is this your schematic ?
https://www.jackssmallengines.com/j...8-041000-049999-compact-pro-34/wiring-diagram
Is your diode in the middle, connected to a yellow/red and red/violet wires ?
The common problem is that those diodes have been probably taken in production from anywhere to get them cheapest... To put any 8A DO-41 packaged instead, would it be ok?
That is the exact wiring diagram and my diode in the middle.