Enginerd
10/9 kW air-cooled Guardian model 5883 running on NG has performed OK for approx 8 yrs until recently when it shut down due to overspeed. Manual restart results in immediate unstable overspeed/underspeed hunting at no load. Stepper motor connection to linkage feels solid w no slipping or grinding while this is happening. Looking through some threads on this forum gives me some ideas of where to start my investigation EXCEPT 1) I dont have a manometer so will take it on faith for now that fuel supply is adequate since other NG appliances show no problems, and 2) I dont understand what the "coils" are or where they are located. If someone could explain or point me to a document that better explains what they are, what they do, and if there is a way to diagnose them, it would be helpful. I plan to dig into this over the weekend starting with air/fuel intake lines and going from there. Any pointers would be helpful.
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Skip Douglas SkipD
A simple U-tube manometer for low-pressure applications is easy to build, very accurate, and quite inexpensive. Materials are all available at a place like Home Depot. The drawing I'm including here shows how simple it really is. The tube and the associated scale would typically be mounted to a board and the board could have a way to hang it or a set of adjustable legs that hold it vertical. Water Manometer Illustrated Build one of these, add a little more tubing and a few fittings, and you'll stop guessing about low-pressure gaseous fuel issues.
Skip Douglas
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SouthLake
would something like this be suitable? its only $50

prob a tool i would like to have on hand while owning the generator.

Natural Gas Pressure Gauge Manometer Kit Tester
Link: [url]http://a.co/j4FZZHr[/url]
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BrentB
SouthLake;52844 wrote:
would something like this be suitable? its only $50

prob a tool i would like to have on hand while owning the generator.

Natural Gas Pressure Gauge Manometer Kit Tester
Link: [url]http://a.co/j4FZZHr[/url]


Similar to what we use everyday in the field!
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SouthLake
thank you brent, sorry for the thread drift.
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HKFever
I would get this...

[url]https://www.amazon.com/Yellow-Jacket-78060-Complete-Test/dp/B0016H12KS/ref=sr_1_1?s=automotive&ie=UTF8&qid=1529103633&sr=1-1&keywords=yellow+jacket+manometer[/url]
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78buckshot
Enginerd, you'll want to check resistance on the stepper motor, unplug it from the controller and check between red and each other color- should be roughly 9 ohms and no continuity to black, rotate the motor and re-check-should read the same as the first readings. Next probable issue would be the ignition coils(magnetos). They send the speed signal to the controller and are a known source of overspeed problems. Coils are labor intensive to replace but no rocket science involved, they are located under the cooling shroud on the right side of the engine.
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Enginerd
Thanks for the comments and sorry for slow response. With oldest daughter graduating from HS I did not get around to doing any work this past week-end and probably won't this coming one either. In the mean time I will order a manometer kit just to put that issue to rest and let you know what I find.
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