Repairing 2200psi Generac Power Washer

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When it was time to power wash the house this year, there was a problem. 2200psi Generac pressure washer that I had bought in June 1999 from Costco quit working. Actually the Honda engine was working fine, but the pump had failed so there was no pressure.

To be fair it was about time. Nothing lasts forever. But I was wondering if I should buy a brand new one, or see if I can repair the pump. When I searched for some kind of repair kit that included all the washers and gaskets, no such thing was available from anywhere. Besides, it would take a lot of time to replace those parts and I wasn’t sure if I could do it with the tools that I had.

The problem for me was that if I ordered a new pump and it did not fit the Honda engine, I would end up with a bigger problem. What would I do with the pump?

But buying a new good quality power washer would cost me a lot and the new power washers mostly come with cheaper pumps to reduce costs to manufacturers.

In my case I ended up ordering a new pump from and it was super easy to install it on our power washer. (3000 psi Model# RMV25G30D-EZ-PKG, item # 30147, $128.98 including shipping). Details below.

2200psi Generac Power Washer


Removing the old pump

Use your proper size allen wrench and unscrew 6 bolts to remove the pump cover.

Pump Cover

The other side.

The Other Side of Pump Cover

This is how the power washer is going to look like.

Cover removed

Remove the second set of bolts with the same allen wrench.

Pistons 1

Pistons 2

The Last Piece

It was super hard to remove the last piece seen above. There are only 4 bolts attaching this piece to the engine, however the problem is that these bolts look like rivets. The top of the screws are circular and none of the wrenches I had would fit. I got stuck here for about a week. I sprayed oil to loosen it. When I tried it about a week later with locking pliers, I finally got these bolts out. The biggest problem was that there was not much space for locking pliers to move. Anyway, if you can remove this final piece, this is how the Honda engine will look like.

Honda Engine without the pump

The New Pump

Here is how the new pump looked like.

New Pump 1

Nwe Pump 2

The new pump had 4 hose connections. The arrows show where the garden hose and the high pressure hose will connect.

The most confusing part for me was the unloader valve. The old pump had an unloader valve with two hose connections. I didn’t see the connections for the unloader valve with the new pump. Northern Tools drop ships this item from a different company (the manufacturer Annovi Reverberi). When I called the manufacturer, it turns out this pump had an internal unloader valve. The adjustment for the unloader valve is the bolt that has a red paint on it. It is factory adjusted to 3000 psi, no need to mess with it.

The hose connection on the high pressure side is used to inject soap or other chemicals into the outgoing water stream. I noticed that if nothing is connected, the water stream looked cloudy because of the air bubbles in the stream. If you put your thumb on the hose connection and close it, water stream becomes clear. I ended up closing this hose barb with a bicycle tire cap. The remaining 90 degree hose barb is used for draining the access water from the pump.

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8 Responses to Repairing 2200psi Generac Power Washer

  1. Michael says:

    My old pressure washer is dying and it’s time for a new one.
    What do you think about this pressure washer
    Best regards!

  2. Herbert says:

    Really this article contains huge amount of information. I think it would be helpful for all. Thank you for sharing with us.
    high pressure cleaner

  3. Bob says:

    Thanks. I was having trouble finding a match for the pump.

    I have a 2600 psi hose. How would I turn down the pressure?

  4. Bob says:

    I bought the aforementioned pump. It bolted right on, although I did need to purchase a shaft key at ACE Hardware. Works great!

  5. Dennis Kauffman says:

    Thanks for publishing this. I have the same (Costco Generac 2200psi) exact power washer and finished the install of the new pump yesterday. I was dreading the removal of the last 4 bolts but found a Allen Wrench socket that fit perfectly with a 3/8 inch breaker bar. My only surprise was the boat load of oil that drained from the old pump when I disassembled the old one. I must say that the difference in pressure is very noticeable from my old one. Thanks again for keeping this online.
    BTW, I was able to find this exact pump online through a Amazon seller for $95.00 with free shipping.

  6. Matt S says:

    I have the same washer and the pump just went so this was a great help. Those final bolts on the old pump are a Torx T30. Also I mistakenly threw out the old keyway with the old pump it is a 3/16 x 3/16 x 2 inch rod that fits in the slot on the engine shaft. Easily found 12 inch stock at Home Depot ($2) and cut to size.

  7. Dave says:

    First of all, many thanks for the very detailed instructions. I have the exact same power washer and the 3/16 Allen key fits perfectly with the final 4 bolts. I need both metric and standard Allen keys to remove all bolts from the pump.

  8. matthew herzog says:

    So I have the same pressure washer and I am adding the same new pump. Where do I find a shaft key that fits the new pump?

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