Yamaha ef1000 will only idle and produce 12 vac

Doe's it have a thermal couple on it? If so it could be bad and when it heats up it is killing your power.

yes this load sensor module has a coil that is wrapped on a single line of stator output.this board may utilize a 12 volt source from alternator

A consumer guide to Yahama's Premium EF1000 with specs, pictures, reviews, and manuals to download. www.poweredgenerators.com www.poweredgenerators.com/yamaha/premium-ef1000.html
hope this will help you

Hi and welcome to FixYa. I am Kelly. Since you did not mention the make or model number of your generator I will respond in generic terms. If your generator is at 127 volts with NO load it is adjust at the very top end of the manufacturers limits. There is a 10% tolerance so 120 VAC + 12 is 127 VAC. Under an electrical load above 500 watts the generator should drop the output voltage slightly so your generator would still be within factory limits. Personally on any generator as a repair person; I set the output voltage at 126 VAC no load so that when the user puts the generator to work the output voltage is good. If your generator is running at 127 VAC under load then you can adjust the governor screw on the governor plate CCW about 1/2 turn to drop the voltage. Without a generator model number or engine number I can not tell you exactly where the governor plate is on your engine / generator. The screw will have a lock nut that you must loosen 1/4 turn then turn the adjustment screw CCW to drop the voltage. Just make sure to re-tighten the lock nut when the adjustments are complete. Mind you by decreasing the output voltage you also drop the output freqency at the same time you decrease the output voltage. It is better to have 125 -127 VAC under a no load condition as the more electrical load you add the more voltage drop you will notice. It is best to adjust the generator to 122.5 -123 VAC under a medium load. (50% of output capacity) A bread toaster is 1400 - 1600 watts and is a good load for a 3000 watt generator. Also a good hand held hair dryer will use around 1600 watts. If you use this type of load and the voltage output is 122.5 to 123 VAC I would not adjust anything. I have been working on generators since 1970 so this is nothing new for me. I hope that you understand everything I posted. If not, feel free to ask as many questions as you wish in any future response.
Thanks for choosing FixYa,
Kelly

1) Check the "Economy Throttle" setting (or some similar verbage). Inverter types dont have to run full speed to produce full voltage.

2) Apply a load. These magically accellerate and decellerate according to load conditions.

Hope this helps,
Dolf-

Tip it over sideways - no drain hole exists, just the inlet.

Hi

You have to find the governor linkage.There is a spring adjusting by a screw to increese speed to get more power.Try to locate it.

best regards savumihai71

My guess would be that some failsafe is in action here. It is possible that either a fuse OR the breaker is bad, or is not resetting in the case of the breaker button. Yamaha likes to idiot proof these things. Some of them disable the sparkplug if the oil gets low. Forget about just a warning light.

Most generators use a flyball type governor within the engine to control rpm; also there is a voltage regulator that tries to maintain voltage at about 115v. The voltage regulator varies the voltage to the armature increasing /adjusting magnetic force. Use a meter with htz or freq setting to adjust engine governor to 60 cycles. When the generator is producing 60 cycles, the engine should be turning 3600 rpm, max power range. At 3600 rpm the voltage should be 115 to 120 volts. Loading the generator will cause governor to try to maintain 3600 rpm. Check engine manual for proper adjustment of gonvernor and linkage. The governor mech should last the life of the engine, however governor system does wear out. Expensive repair. enjoy