Mercury Mariner Outboard 225 3 Litre Service Manual 1994, Page 59Get this manual
Checking Positive Brushes and Terminal Set ohmmeter to (R scale)Connect meter leads between POSITIVE brushesMeter must indicate fu ll continuity or zero resistanceIf resistance is indicated, inspect lead to brush and lead to POSITIVE terminal solder connection1f connection cannot be repairedbrushes must be replaced STARTER REASSEMBLY 1If brushes were removed, replace as follows: aInstall POSITIVE brushes (along with POSITIVE terminal) into commutator end cap
a POSITIVE (t) Brushes
Testing Negative Brushes for Ground Set ohmmeter to (R xl scale)Place one lead of the ohmmeter on the NEGATIVE brush and the other lead on the end cap (bare metal)If the meter indicates NO continuity, replace the NEGATIVE brush Repeat this procedure on the other NEGATIVE brush