No pressure....can't figure out why!

4 years 3 months ago #3387 by robweatherfan
No pressure....can't figure out why! was created by robweatherfan
I have a Generac pressure washer, about 2700 psi. Last summer lost all pressure. About same time engine began surging (up and down rpm's) while idiling. Replaced unloader valve and still no pressure. Later, in fall, still surging at times and even not running, at times, without choke being part way on.
Recently I took apart and cleaned the carburetor. It looked pretty clean when I got in there, but I think it helped. Now runs with very little surge and without choke applied. It even produced pressure for a few seconds before it ran out of gas, but now no pressure again!
When engine is running and there is no pressure I hear some rattling in area of the pump.

If anyone has any ideas, please help!

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4 years 2 months ago #3388 by MTR-Admin
Replied by MTR-Admin on topic No pressure....can't figure out why!
What type of gun do you have? Also, do you have the model number?

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4 years 2 months ago #3390 by robweatherfan
Replied by robweatherfan on topic No pressure....can't figure out why!
Thank you Administrator for replying, but I'm ok now.
I took the pump off of the engine shaft and was able to spin the pump "shaft" freely....no grinding or noise. I also took the unloader valve out of its seat, but I doubt this affected anything since the unloader valve is new. Also, there's a very narrow, inch long piece of metal that fits into a groove on the engine shaft where the pump slides over it. That fell out and I slid it back in.

When I put it back together it worked! I used it for over 30 minutes.
Feel free to let me know if you have any idea what the problem could have been.

I gained some good experience along the way for future repair work!:)

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4 years 2 months ago #3391 by MTR-Admin
Replied by MTR-Admin on topic No pressure....can't figure out why!
Great, glad to hear that you found the problem. That piece of metal is called a 'key'.
Happy new year.

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4 years 2 months ago #3399 by robweatherfan
Replied by robweatherfan on topic No pressure....can't figure out why!
Hey, thanks for the key info. Hope you had a good New Year holiday.
Maybe talk to you on my next forum question.

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7 months 6 days ago #3780 by jegego
Replied by jegego on topic No pressure....can't figure out why!
It sounds like you've been through quite a journey with your Generac pressure washer. Dealing with pressure loss and engine surges can be frustrating. Kudos for your troubleshooting efforts so far, like replacing the unloader valve and cleaning the carburetor.
Since you mentioned hearing some rattling around the pump area when the engine is running but there's no pressure, it might be worth checking for any loose components or debris around the pump. Also, make sure all connections and hoses are properly secured.
Considering you saw some improvement after cleaning the carburetor, there's a possibility that there might be some fuel delivery issues affecting both the engine and the pressure generation. Double-check the fuel lines, filters, and ensure proper fuel flow to the engine.

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