Briggs 7.8hp will not run more than 10 seconds

rszanti · Jun 22, 2016

I have a Briggs 7.8hp engine on a Sears power washer that was purchased new, run about 4 hours and suddenly won't keep running after starting. I start it, the engine runs for 6-10 seconds and quits. It will immediately restart but then quits and on and on. I have removed, cleaned and reinstalled the carb. Cleaned the tank and added new fuel. The fuel line is clear. I removed the gas cap suspecting a vacuum lock but it didn't help. I know engine has a low oil pressure switch and wonder if this could be it. Or is there some other module that could cause this type of failure ? Any suggestion would be appreciated.

Richard

Midniteoyl · Jun 22, 2016

rszanti said:
I have a Briggs 7.8hp engine on a Sears power washer that was purchased new, run about 4 hours and suddenly won't keep running after starting. I start it, the engine runs for 6-10 seconds and quits. It will immediately restart but then quits and on and on. I have removed, cleaned and reinstalled the carb. Cleaned the tank and added new fuel. The fuel line is clear. I removed the gas cap suspecting a vacuum lock but it didn't help. I know engine has a low oil pressure switch and wonder if this could be it. Or is there some other module that could cause this type of failure ? Any suggestion would be appreciated.

Richard

How new is it? Still under warranty, take it back..

You can bypass that low oil switch. Had to do it on a Generac that did pretty much the same thing.

rszanti · Jun 22, 2016

Midniteoyl said:
How new is it? Still under warranty, take it back..

You can bypass that low oil switch. Had to do it on a Generac that did pretty much the same thing.

Despite low usage it is way out of warranty, no luck there. Bypassing the oil switch ... short it out or disconnect it ?

bertsmobile1 · Jun 22, 2016

If it is new, take it back or get the Sears tech to come & have a look.
Of all the big box stores they are the only ones worth a dime and the only ones that stand behind what they sell.

If it is older then get an inline spark tester and watch to see if the spark stops before the engine starts to run down or weather the engine runs down , sparking all the way.
You have then cut the diagnosis time in 1/2 as you have eliminated either fuel or electrics.

The low oil cut out is low volume not pressure so check the oil level is right at the top of the mark, then add another 4 oz, no more.
When the engine spins and oil gets tossed around everywhere the oil level in the sump drops and some time it can be just enough to trigger the switch, paticularly if the unit is sitting on a slope.

Finally is you want more help from this frum we will need the model & code numbers from your engine.

Midniteoyl · Jun 22, 2016

rszanti said:
Despite low usage it is way out of warranty, no luck there. Bypassing the oil switch ... short it out or disconnect it ?

If I remember, I just disconnected and taped the wires. The switch is actually a pressure switch, but they clog up unless the oil is changed like every 50 hrs. Mine was also a 7.8hp..

John R · Jun 23, 2016

bertsmobile1 said:
If it is new, take it back or get the Sears tech to come & have a look.
Of all the big box stores they are the only ones worth a dime and the only ones that stand behind what they sell.

If it is older then get an inline spark tester and watch to see if the spark stops before the engine starts to run down or weather the engine runs down , sparking all the way.
You have then cut the diagnosis time in 1/2 as you have eliminated either fuel or electrics.

The low oil cut out is low volume not pressure so check the oil level is right at the top of the mark, then add another 4 oz, no more.
When the engine spins and oil gets tossed around everywhere the oil level in the sump drops and some time it can be just enough to trigger the switch, paticularly if the unit is sitting on a slope.

Finally is you want more help from this frum we will need the model & code numbers from your engine.

They did before Kmart bought them out.

rszanti · Jun 23, 2016

Our local Sears doesn't seem to do repairs anymore, at least I keep getting a run around when I ask. And only one local mower repair will even agreed to work on a Sears machine, they all claim Sears is next to impossible to work with. Sears has also eliminated repair part stores/warehouses in the area, everything in parts is now mail-order.

BlazNT · Jun 24, 2016

Our sears repair is in Kansas city. 3 hour drive. Used to have one here but every thing has been consolidated. So if you bring it in for repair it sits in store until truck leaves on thursday.

rszanti · Jun 24, 2016

And the problem was a bad pressure switch as suggested. Thanks for the help. A $22 replacement sure beats the $177 the local Authorized Briggs dealer suckered me out of.

Thanks again
Richard

Midniteoyl · Jun 24, 2016

rszanti said:
And the problem was a bad pressure switch as suggested. Thanks for the help. A $22 replacement sure beats the $177 the local Authorized Briggs dealer suckered me out of.

Thanks again
Richard

Nice... I just left mine disconnected. I check the oil before every use and during every refuel anyway.

Briggs 7.8hp will not run more than 10 seconds

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