The Tecumseh OVXL120 on my 1983 MURRAY lawn mowe is getting really hard to start just this year. It's been used sparingly a few hours per year. Once you place a marine bat in parallel with it's bat it starts and runs fine. Bat is checked and ok. Starter solenoid was jumpered out for test and no change, turns over slow with one bat. When running all is fine. Could the starter need rebuilding, ie. bushings etc. Connect bat to starter post and turns over slow, bypassing key, solenoid etc. It runs well once I get it started, but its really hard to start. Will only crank slow with it's own bat.