FSX-MS Leaning mixture on aircraft without EGT or Fuel Flow gauge

[DarkPhoenix 2]

is there a proper way to lean mixture on aircraft like DHC-2 Beaver or Grumman Goose? Those do not have EGT or Fuel Flow gauges, which is what I have read is used to determine how to lean mixture.

I can wing it (pun not intended) with 15% per 1000ft seemingly working fine, but would like to know he proper way of doing this.

[DavidP 1,410]

Don't know about those specific types but on smaller GA types you would lean the mixture just to the point the engine begins to run rough, then richen the mixture a little until the rough running ceases.

[stans 703]

As you lean the mixture, watch the tachometer.  Lean until the RPM begins to drop from its maximum, then enrich the mixture just enough to get it back to that maximum.

[DarkPhoenix 2]

Those sound like good guidelines, thank you!