Generac Pressure Washer Pump Repair

[polarred21]

Any pressure washer pump gurus here? Just a wintertime project, yeah yeah I know, go electric. This is my brothers ( I also have the identical unit) that has been sitting for 10 years, and moving forward with troubleshooting and possible repair. This model 20 years ago was about $299, and appears they are $399 today so maybe worth a little effort while ensuring not throwing good money after bad.

This is a Generac 2400 psi Model G24H, and I have the parts manual. Only trouble mine has given all these years is the small chemical tube valve needed replacing once.

I flushed everything out and changed the oil, all looked good.

Test run last week:
- Hooked up water hose, no water would flow through.
- Pulled about 10 times and it started strong, shut off several times, kept restarting.
- Pump worked fine under pressure, but acts like unloading valve stuck or something, only stays running while holding the wand trigger.
- Motor will shut down on it's own, with low load, I think that's something to do with oil pressure diaphragm valve that restricts fuel flow.
- New oil is now contaminated with water I think, this has to be verified.

So looks like I will remove the pump and go from there. This is where I need help. Maybe I can disassemble and clean it up, new one is $80.

 

[D&D]

.Test run last week:
- Hooked up water hose, no water would flow through.
- Pulled about 10 times and it started strong, shut off several times, kept restarting.
- Pump worked fine under pressure, but acts like unloading valve stuck or something, only stays running while holding the wand trigger.
- Motor will shut down on it's own, with low load, I think that's something to do with oil pressure diaphragm valve that restricts fuel flow.
- New oil is now contaminated with water I think, this has to be verified.

So looks like I will remove the pump and go from there. This is where I need help. Maybe I can disassemble and clean it up, new one is $80.

I like to fix vs toss whenever I can. Sometimes a tough decision with parts pricing. IMO, I would separate pump and motor, solve engine issues first. Is there a rebuild kit available for the pump? That model # doesn’t work for me

https://www.jackssmallengines.com/jacks-parts-lookup/manufacturer/generac-engine-part/pressure-washer

 

[YanmarFever]

I just repaired our little Honda washer, I bought a new pump off eBay and popped it on, only 75 bucks.
Also I ran some cleaner thru the carb to clean out the old gas residue (sea foam).

When washers sit for a long time corrosion eats the pump inside unless you run this or similar thru them.
Its cheap insurance..

 

[ponytug]

I just repaired our little Honda washer, I bought a new pump off eBay and popped it on, only 75 bucks.
Also I ran some cleaner thru the carb to clean out the old gas residue (sea foam).

When washers sit for a long time corrosion eats the pump inside unless you run this or similar thru them.
Its cheap insurance..

I lost a pump due to internal corrosion. Afterward, I am better about blowing it out when I'm done, but using a protective lubricant seems like a better way. I made up and adapter of a 1/4" air hose Q/C to valve to a 3/4" coupling to a male GHT. (Or buy it from Amazon, $8-12. I had the parts around.) My new pump came with specific instructions not to use hard water, something that the original owner's manual neglected to point out due to the risk of debris.

Personally, I am in the fix vs dump category as well, and I am certainly guilty of not always valuing my time for what it is worth. Sometimes, it is just entertainment for me. YMMV.

When you start it with the pressure port open, how easily does it turn over? If it isn't easy, I think it might be worth putting some lubricant into the pump (WD-40, or the above mentioned pump protector), and having a look see at the unloaded valve first. If it is easy, I would bet on a stuck unloader valve or gunk in the carburetor.

All the best,

Peter

 

[5030]

Honda GC motors are basically throw away motors anyway and they seem to suffer carb issues quite a bit as well, Think I'd start with the carb on the engine first.

 

[mrmikey]

Afterward, I am better about blowing it out when I'm done, but using a protective lubricant seems like a better way

Same thing I do with mine when I'm done with it, I use plumbing AF every time when I'm done with it, never lost a pump to corrosion yet. Mind you, I did lose a pump due to the 1/4" key wallowing out the groove on the pump coupler so it was almost 1/2 the circumference of the collar wide and about double the width of the keyway on the pump motor, took about 5-6 years of use.

 

[5030]

Been running the same cheap azzed HF gas driven pressure washers for at least 10 years (Pred motor is still on the original plug) and no issues and I never drain it or anything, when I change the oil in the engine (yearly), I change the oil in the pump as well. It does stay in the heated shop in the winter however. I did replace the cheap azzed HF hose with a real one a few years ago, however and I just replaced the 'wand' with a new one as well because the original one pooped out. Best 230 bucks I ever spent.

 

[Menagerie-Manor]

Any pressure washer pump gurus here? Just a wintertime project, yeah yeah I know, go electric. This is my brothers ( I also have the identical unit) that has been sitting for 10 years, and moving forward with troubleshooting and possible repair. This model 20 years ago was about $299, and appears they are $399 today so maybe worth a little effort while ensuring not throwing good money after bad.

This is a Generac 2400 psi Model G24H, and I have the parts manual. Only trouble mine has given all these years is the small chemical tube valve needed replacing once.

I flushed everything out and changed the oil, all looked good.

Test run last week:
- Hooked up water hose, no water would flow through.
- Pulled about 10 times and it started strong, shut off several times, kept restarting.
- Pump worked fine under pressure, but acts like unloading valve stuck or something, only stays running while holding the wand trigger.
- Motor will shut down on it's own, with low load, I think that's something to do with oil pressure diaphragm valve that restricts fuel flow.
- New oil is now contaminated with water I think, this has to be verified.

So looks like I will remove the pump and go from there. This is where I need help. Maybe I can disassemble and clean it up, new one is $80.

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Have owned a similar model for almost 20 years and was having similar issues so rather then compounding frustration I grabbed a new carb and pump off Amazon for like $120. Dam thing is performing like new...

 

[polarred21]

Thanks for the feedback. I'm now finding a model number 1675-0 on the manual, so that is getting some interweb responses. Sticker on machine is G24H.

Last week I removed the gas tank and carb float bowl. Flushed out with carb cleaner and fresh gas, was not too bad. Feeling pretty good about the carb, runs strong and steady at factory set high idle for maybe 3 seconds. Leaning towards the oil level sensor/fuel shutoff for this issue, I may remove it and bypass to see it will work this way.

Didn't have time yesterday to get back on this due to final leaf mulching, hopefully soon.

Pump is free and will spray at pressure. The pump is actually choking off the engine when closing wand trigger because pressure won't relieve, so when I pull the pump I'm hoping I can start engine without it for further engine troubleshooting. I will evaluate the pump then and most likely order one, although I will take it apart and see what I can do with it.

Parts manual says my pump number is 189943GS. Search info states that 189943GS replaced by 317054GS. Won't be getting this one

 

[Menagerie-Manor]

Thanks for the feedback. I'm now finding a model number 1675-0 on the manual, so that is getting some interweb responses. Sticker on machine is G24H.

Last week I removed the gas tank and carb float bowl. Flushed out with carb cleaner and fresh gas, was not too bad. Feeling pretty good about the carb, runs strong and steady at factory set high idle for maybe 3 seconds. Leaning towards the oil level sensor/fuel shutoff for this issue, I may remove it and bypass to see it will work this way.

Didn't have time yesterday to get back on this due to final leaf mulching, hopefully soon.

Pump is free and will spray at pressure. The pump is actually choking off the engine when closing wand trigger because pressure won't relieve, so when I pull the pump I'm hoping I can start engine without it for further engine troubleshooting. I will evaluate the pump then and most likely order one, although I will take it apart and see what I can do with it.

Parts manual says my pump number is 189943GS. Search info states that 189943GS replaced by 317054GS. Won't be getting this one

I grabbed this oem pump and it works great.

Amazon.com

 

[ponytug]

Funnily enough, mine (same design, but not Generac) would not start today. After checking for spark, and enough oil, I drained and pulled the fuel tank to get to the carburetor, opened up the carburetor drain screw, and shot some acetone (brake cleaner) up into the carburetor, and let it drain, a couple of times. The last squirt I left in the carburetor and tried starting the engine. It ran on acetone, so I drained the acetone, reinstalled the fuel tank, added back the gas that I had drained out, and changed the oil because I might as well since I am into the machine anyway. 20oz per the manual 10W30.

FWIW: The carburetor drain screw is on the other side from the fuel pump, and you don't have to pull the fuel tank to get to it.

Runs great now! My note to self is don't leave gasoline in the carburetor too long.

All the best,

Peter

 

[polarred21]

So last weekend removed the fuel pump and tried to bypass it, would not start, duh.....blew it out good, another drain and flush, and engine starts and runs flawlessly. Let it run several minutes with no water in the pump, didn't care about the pump at this point.

So spending just a little time on the pump, full of oil, looks okay. Had to get cutoff wheel to remove plastic hand sleeve at pump hose connector, seems the aluminum and brass have married to each other over time. A little heat and got it removed. Pulled the unloader valve and top valve body to find it full of corrosion, feels like salt inside. Cleaned and lubed with marine grease and had to stop, has sat for a week. Will test the pump once more and go from there.

 

[ponytug]

Great news on the fuel pump! Congratulations.

That crud looks like either hard water or aluminum corrosion salts from water bypassing the unloader valve. If the unloader cylinder walls aren't too scored, I would clean the walls out, clean the unloader assembly, replace the o-rings, and you should be back in business. I would measure the thread length, or spring compression length or both before disassembly, otherwise you will need to be adjusting it with a high pressure gauge.

All the best,

Peter

 

[polarred21]

Well that's a wrap. Maybe 6 hour total labor and zero expense required. Works like a new one. Did buy the $30 pressure gauge to set to pressure. Rated at 2400 psi, can only get 2000 psi with trigger pulled, set relief pressure at 2400 psi.

Other than usual gas issues with the engine and carb, cleaning and flushing was all that needed. Did replace the suspect hose from the crankcase to the diaphragm fuel pump.

The pump itself was really cruddy inside from the breakdown of the aluminum and other metals on well water. Had to disassemble twice for cleaning and liberal with marine grease. Changed oil in the pump, there is no drain plug. Will definitely be lubing my pumps now periodically.

Washing one relic with another....

 

[CADplans]

I just went through the pressure washer parts hunt,,
I could not figure out what I needed to order, a replacement pump was under $200,,
so, I figured ,, what the heck, get a pump.

4GPM at 3600 PSI,, I really enjoy the pressure washer.
If this pump does not last, I will get the CAT pump,, but, that pump is $800,,,

I probably lost the old pump to corrosion/freezing,, who knows,, can't cry about it, I got over ten years out of the original pump.

The 13HP Honda runs like new,,
I almost got it out today,, the weather was so nice,,

I am thinking about building a storage box for it, and adding a heater to the box to stop freezing.

What about running old hydraulic oil through the pump??
That would stop freezing, and lube the pump.
I have LOTS of clean hydraulic oil every time I change the hydraulic oil in a tractor,,
Hmmmmmmmmmm,,,