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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

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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.

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.

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

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.

rszanti said:

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

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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..

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.

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They did before Kmart bought them out.

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 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

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

rszanti said:

Would definitely be cheapest way to go but the switch actual protects against low oil pressure which could be caused by problems other than just low oil. So I am going to replace it.

Richard

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Very smart move:thumbsup:

rszanti said:

Would definitely be cheapest way to go but the switch actual protects against low oil pressure which could be caused by problems other than just low oil. So I am going to replace it.

Richard

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Eh.. If the problem caused by something other than low oil it'll just give me an excuse to get a bigger genset :thumbsup: This ones 17yrs already..

rszanti said:

Would definitely be cheapest way to go but the switch actual protects against low oil pressure which could be caused by problems other than just low oil. So I am going to replace it.

Richard

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I don't think your engine has any oil pressure, it's splash lubricated.

That switch is for low/no oil.

John R said:

I don't think your engine has any oil pressure, it's splash lubricated.

That switch is for low/no oil.

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You know that, & I suspect that but as the owner never bothered to post engine numbers so it could be checked out it was not worth contradicting .
I have never seen a pressure switch in any briggs engine ever .
The only switches I have ever seen are oil level switches even up to the 28 HP Professional units fitted to skid steers

rszanti said:

My apologies to the group (and to Briggs & Stratton), I have discovered since starting this thread that the engine may be a 7.8hp "Generac" model. In any case there is a B&S parts listing I got from the Sears website which does list an 8psi pressure switch (not a level) even though I can't find an oil pump in the parts list (?????) or parts diagram. And the switch definitely appears to be a pressure switch, at least from the outside. My replacement arrives tomorrow so I'll know for sure after I do the exchange.

I cannot find an engine model number on the engine. It was the Sears part listing that led me to believe the engine was a Briggs. But photos I've looked at in Google lead me to believe it is a Generac. The two are so close together in size etc. it's hard to tell. Very confusing !

Richard

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I'm sorry, I thought you knew that? The 7.8 is indeed a 'Generac' (thus its use on Generac GenSets like mine) but I believe in 1998 the smaller portables were sold to B&S under an agreement, but was regained by Generac in 2007. This is why you see B&S 7.8hp 'Generac' engines. They are the same.

The switch is a pressure switch, but the pressure required to activate it is very, very low and is used as an indicator of low oil. Thats why I just went ahead and pulled the wires instead of constantly cleaning/replacing it.