Question-------------------------
Follow-up....
Eric the only other question I would have would be to ask you for your ideas on what might be making this onan emerald 1 genset not be able to find a happy speed under load and no load condition. This thing wants to surge the rpms up and down, back and forh. I know this generator did sit for a while and was not used. It's in a 1988 honey motor home. I pulled the bowl off the carb and there was some sediment in the bottom. The float, needle and seat appear to be ok. One thing I notice is the main metering jet on the bottom of the bowl and the slow speed mixture do not seem to respond like i am used to seeing. Could it be that it just needs a re-build? Thanks again Eric!
Randy Simmons
Hartland, Mich
Question -
Hi Eric, I am trying to trouble shoot my onan generator in my motor home... can you tell me how to monitor or check the frequency in "hz"? The info i have seems pretty easy to follow for what i need to do, just don't know how to check the frequencys at "load" and "no load" as is suggested in the info i have. Is it done with a scope maybe? If so, could you tell me how it's done? You most likely know this is how to set the proper operating speed and also how to properly adjust the govenor.
Thanks Eric for any assistance you may be able to give me! Randy
Answer -
A scope will work, a gen set tester or DMM with a frequency counter will also work. I have seen DMM with Dwell and freq counters for sale at many auto parts stores and even Sears.
As for the frequency, it is actually controlled by the engine rpm, 3600 rpm for a 2 pole generator. Of course you have some tolerance, +/- 100 rpm. Many mower shops sell single/small engine tachometers, but a digital or analog meter can set you back a lot of money. I have seen people use the "Tiny Tack" to check the engine rpm.
Anyhow, I would set the governed speed to 3600 rpm, and then confirm the frequency, 55-65 Hz. Most appliances don't care is the frequency is off a little...drills and other power tools are a good test to roughly check the frequency.
Let me know if you have any other questions.
Eric
AnswerMost likely the problem in the carburetor. All the manuals and classes say that 99% of surging is related to a carburetor problem, not a governor problem.
I would clean the carburetor with compressed air and carburetor cleaner.
On a side note, generator governor springs do tend to be more sensative; they need to be sensative to respond to varing loads. We normally replace the governor spring if the engine comes in with a surging problem. The only problem with replacing the spring is that the spring tension may need to be set. Typically it is 3600 RPM for generators. I would recommend a decent analog or digital tach for govern spring setting.
Clean the carburetor and let me know what happens. Also, make sure all the intake gaskets are sealing...the should not be hard or brittle.
Eric
