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WashWhiz

Unloader Valve? Or Pump?

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I do small pressure wash jobs part time to supplement my retirement income.  I wouldn't call myself a highly experience expert, but I'm no dummy either and I know how to diagnose and fix all the common problems.

I have Troy-Bilt XP washer, model 020489, with Honda GCV-190 engine, Annovi Reverberi pump 3000 PSI 2.7 GPM.  It has probably a couple of thousand hours on it, but I keep it clean, change the oil, and do all the maintenance.  I treat it like the money-making piece of business equipment / expensive tool that it is.

On a recent job, towards the end of the day, I lost pressure.  The symptoms indicated a stuck unloader valve, and upon inspection, it was indeed stuck.  No amount of fiddling with it and carb cleaner, brake cleaner, and PB blaster would unstick it.  Had to quit for the day.  I ordered a new unloader valve.

In the meantime, I left the old valve soaking in PB blaster.  After 2 days of soaking, it came unstuck.  Not trusting it, I installed the new valve on my washer when it arrived.

When I fired up the washer, the engine is running all-out, several hundred RPM above normal, and I still no pressure (beyond what you get from the faucet).  OK, so I figured the new valve needed adjusting.  Never had the need to adjust one before, the factory adjustment on the old one worked fine.  After much fiddling and adjusting following many different people's instructions, I was unable to solve the problem.  (Engine still running fast, poor pressure).  I reinstalled the old valve which still had the factory adjustment that had been working great.  And I STILL have the same problem.

So whadda ya think?  Is this an unloader problem, or has the pump failed?  Maybe a broken or stuck leaf valve in the pump?

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On more careful consideration, there is probably around 500ish hours on the pump, not 2000.  But even at 500, the pump has probably reached the typical end of life, so if I have to get a new one, I won't be too upset.  Don't wanna buy one if I don't need to tho!

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My guess would be the pump is shot. If you got 500 hours out of it I would be happy.  I've went through a few homeowner units and failure has always been due to the pump. I also constantly see broken units on craigslist for cheap because there's no pressure.

I bought a rebuild kit once for my Honda GC Craftsman homeowner unit once and it fixed the no pressure issue. It was less than $30 too. Instead of buying  a whole new pressure washer you could also just buy a replacement pump and throw it on your current engine. The pump is only held on by 4 bolts. Just be sure the pump specs are the same. I think my GC190 came with a pump with 2.8 gpm and 3200 psi pump so you may have a little room to play with in finding the right pump. You can get a pump on ebay for around $80 although I'm sure the quality isn't the best.

If you plan on buying a new washer I think I would try and find a decent used pro washer especially if you put a lot of hours on it. The more gpm the better.

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Yeah, I would check into the pump. Sounds similar to a condition I have experienced.
Pump wasn't that old either but it was used on a 2 gun machine so it was put to work a great deal.
When the tech took the pump apart to take a look inside, the entire gear/piston assembly had just
collapsed and was a mangled mess.

Scratching my head, we ordered a new pump and back to work I went.

Rod

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Wow, what a headache this has turned into.  Yes, it was indeed the pump.  Turns out the shaft-keyway-key had sheared off, and in doing so, broke the top of the shaft socket on the pump and causing it to leak out it's oil.  The engine shaft was OK.  So I ordered a new pump and a key that was supposed to fit, but didn't.  Best price I could find on the pump was $124.

The key that was supposed to fit was just a hair too big and I wasted several hours and a lot of cussing trying to get the pump on.  Ended up having to make a key from bar stock.

Once I finally got the new pump on and tried it, the engines wasn't running right.  Too high of an RPM when the trigger was not depressed, and to low of an RPM and struggling when I pulled the trigger.  Ran for a bit, then backfired and died and would not restart.  Took it to my nephew who works on small engines and it has no compression, and at the very least has broken a ring and will need to be rebuilt.

 

When it rains, it pours.

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I agree that if you are actually making money at this, even a little, you should step up to a 4 gallon per minute machine which is way faster. Also you'll have enough power to use a bigger Surface Cleaner which is faster still.

You can find used machines for around 500.

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