20 Most Recent Yamaha 1,000 Watt Portable Generator #EF1000ISC - Page 7 Questions & Answers

there are a couple listed on ebay in the $10 range

replace it

This is official site: http://www.yamaha-motor.com/outdoor/products/modeloverview/cat/2007/55/model_overview.aspx

Now if the genset stabilises with a load but keeps shunting when there is no load it is possible that you need to do a service check or overhaul of the engine.
1. Make sure that the oil is clean , if low or clogged replace the oil.
2. Check the fuel line and the fuel/air settings . If the engine is HUNTING then there is a setting fault of the mixture or there is dirt in the carburator ports that does not allow the fuel to be flowing with the right pressure . It is best to remove and clean the system.
3. The Spark plug is another reason, if the plug gaps are low, if the spark plugs are bad, insulation is faulty the power will be reduced as it will hunt.
4. The genset RPM is monitored by a governor which allows a slight throttle adjustment when the load increases. So make sure that the linkages to the throttle vavle is free and moving.
5. the choke must be kept closed, check the spark plug to have an idea of the firing.Finally check the fuel, check for impurities in the tank.
I am sure one of the above tip must solve the issue.
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