Retired Wrencher 6,262 #1 Posted September 20, 2025 Does anybody have an idea how many amps you need to turn over a 10 hp Kohler with a starter generator? Is it 50 A or more? I found a heavy duty one with 20 apps is that enough? Share this post Link to post Share on other sites
pfrederi 19,459 #2 Posted September 20, 2025 (edited) The S/G just takes battery amperage to spin the engine. As a generator the old S/Gs only made about 12 amps. They are rated usually on the output. Edited September 20, 2025 by pfrederi Share this post Link to post Share on other sites
Retired Wrencher 6,262 #3 Posted September 20, 2025 (edited) Thanks, Paul I’ll look into that. So 20 A would be too high. Edited September 20, 2025 by Retired Wrencher Share this post Link to post Share on other sites
pfrederi 19,459 #4 Posted September 20, 2025 4 minutes ago, Retired Wrencher said: Thanks, Paul I’ll look into that. So 20 A would be too high. Not a problem the regulator (if it is working) will limit the output to what is necessary to charge the battery. If battery was really low a 20 amp genny would just charge it slightly faster than a 12 amp Share this post Link to post Share on other sites
Retired Wrencher 6,262 #5 Posted September 20, 2025 Just now, pfrederi said: Not a problem the regulator (if it is working) will limit the output to what is necessary to charge the battery. If battery was really low a 20 amp genny would just charge it slightly faster than a 12 amp I would like to find what out what original switch was for amperage. Share this post Link to post Share on other sites
squonk 45,058 #6 Posted September 20, 2025 (edited) To START an engine you're looking at close to 80 amps to get things rollin and about 50 amps to keep it crankin. I tested an 8 HP on my engine stand with a clamp on ammeter. Charging amps are much less. Stock HD switch without using a solenoid https://wheelhorsepartsandmore.com/product/4988-7263-starter-generator-key-switch/ Edited September 20, 2025 by squonk 2 1 Share this post Link to post Share on other sites
Handy Don 15,605 #7 Posted September 20, 2025 35 minutes ago, squonk said: To START an engine you're looking at close to 80 amps to get things rollin and about 50 amps to keep it crankin. I tested an 8 HP on my engine stand with a clamp on ammeter. Charging amps are much less. This makes perfect sense, thanks! 2 Share this post Link to post Share on other sites
ri702bill 10,958 #8 Posted September 20, 2025 Best to add a solenoid to take the heavy current out of the switch...... 3 Share this post Link to post Share on other sites
953 nut 63,546 #9 Posted September 21, 2025 Use the much more affordable 103990 ignition switch and a solenoid. 2 Share this post Link to post Share on other sites
