Suzuki Generator - runs too fast?

Hi All,
You may remember, some time ago I posted about my Suzuki SE700A 4-stroke briefcase generator. Well, I got it running at last, all it needed was a new spark plug in the end....

The problem I have with it, is when I start it, it seems to run very slowly (so slowly you can count the engine firing at about 2/3 per second), and then when i push the choke all the way across, it starts revving up and down....at this point i get worried it's going to blow up or something, so I reduce the choke to the middle position, where it starts to run nice and smoothly, just waaay to fast (it makes a sort of continuous 'screaming' noise instead of a generators usual ticking over sound)....This is with no load, when I use my 300 watt electric strimmer, the engine slows right down to what I would call the right speed (I can only tell this from the way it sounds, and the way I have heard other generators sounding), however, I am too scared to plug any sensitive equipment into it when it's idling, for fear of blowing it up!!

Am I right in thinking this could be something to do with the governor?

Any help/opinion would be appreciated!

Thanks and blue skies,

Chris.

 

Sounds like she is running to lean. Typical symptoms are the constant surging up and down speed. Second is the high speen at open throttle. You would have to back out on the mixture adjusting needle valve on the carburetor. Just tune it by ear.

 

OK thanks mower,

I'll give that a try and let you know how it turns out.

Does anyone have any idea of how you adjust the mixture screw? The carb is called a 'Mikumi'

Thanks,
Chris.

 

check to make sure that the fuel line does not have a crack anywhere...if engine is running slow (starved for gas ) and then choke is applied..this causes more gas to be sucked in with a gulp of air causing motor to take off like full throttle

 

white_elephant,

Clean the carb thourghly.Rebuid with the proper rebuild kit. Readjust mixture screws for proper operation after carb rebuild. The engine should run at 3600rpm's with or without no load on the armature. It should have none or minimal hunting or surging with no load, and absolutely no hunting or surging with load applied. Also, you are correct in not pluging in an electrical load that is sensitive to cycle deviations by the hunting and surging of this engine.

God Bless
Dave237

 

Correct, a carb recon is in order. Don't plug any sensitive equipment into it unless you can get it running at 60 hertz with minimal variation. Even then, I would reccomend using a surge protector or capacitor inline before running something very sensitive.

 

hello,

Cheers guys!
I'm gonna give all that a try - just one more thing....

I'm based in the UK so i need a 50Hz power supply, i've heard somewhere that that means the speed should be 3000rpm - Is this correct?

Thanks again,
Chris.

 

hi chris

sounds like your throttle plate is stuck open--did you check that ? Sticky old stale gas does that.

S/T

 

I don't know what rpm would yield 50 hz. I'm not sure how you would measure it either unless you have an oscilliscope. Maybe an electrical shop could help you with that?

 

white_elephant,

If your armature is of standard configuration, 2500 rpm should yield 50 htz however, this will depend on the generators exact armature, internal electronics and the fact that your mains voltage is 240V, you may need a different speed.

An inexpensive multimeter with a frequency meter can be obtained at radio shack for about $60.00 to $80.00US. However, they are not very accurate at these frequencies but can put you in the ball park. A few cycles on the high side should not get you into trouble as long as you’re not using it to power computer equipment. You don’t want to go below 50htz. This can cause internal over heating of transformers due to magnetic eddy currents and power supply failures.

If you decide to handle this by yourself just be very very careful. One wrong move and you’re toast!!!! You may just want to follow Cheese’s advice... his is by far the safest and most accurate....!

God Bless
Dave237