# Sounds like backfire???



## ebforce (Feb 16, 2018)

Hello, I am new to the forum.

The Equipment is an older Sentinel 9 (KW), B&S Vanguard 18 with an unknown generator, runs on LNG, motorized transfer switch. Lately, the engine started stalling after a short run and backfiring (I think into the carb)

I inherited the unit with the house a few years back, fresh oil, plugs, filters, etc. 

Kindly please look at my videos. I would greatly appreciate any pointers or at least confirmation that it is in fact backfiring.

The first video is a start and stall (starter keeps running)
The second video it actually starts and runs with hickups for some time.

https://www.dropbox.com/s/79j8e3og1p6mk1b/VID_20180216_143530.mp4?dl=0
https://www.dropbox.com/s/7o080bgivr9m2qp/VID_20180216_143622.mp4?dl=0


Thanks, Igor


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## thehandyman1957 (Feb 11, 2017)

This sounds more like a fuel delivery issue to me. LP engines do this when the fuel is not regulated properly or pressure is not right.

I would see if you can find someone who might be able to check your carb regulator and also test your LP Low pressure side for both pressure and flow.

Did you get a new batch of LP lately?


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## KRE (Nov 29, 2011)

Are you sure of your fuel ? There is a difference between LNG an Propane an gas settings for a heat engine are totally different. Depending engine speed a spark timing difference as well.

North of 56 | Energy | LNG vs. Propane


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## ebforce (Feb 16, 2018)

Thank you for the comments everyone. 

Here is some more background on the equipment. The generator runs on natural gas and not propane. The gas line from the meter runs into this solenoid valve

https://powerparts.ecrater.com/p/28451821/eaton-snc-1014-31b-valve-natural

and then into the Garret adjustable pressure regulator, it might be in the opposite order though. 

This rig has been operational for at least a year with no issues. I believe what you guys are suggesting is that the Garreth pressure regulator is failing as the adjustment on it has not moved.

Interestingly enough, upon stalling the starter continues to run for another 10-15 seconds until the thermal breaker kicks it out. Based on that I could speculate that the shutdown/stall is not logic directed.

Thanks again!


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