old pressure washer help

[mopar4u]

got this old timer for free, he said no water comes out at all. looks like it has a newer hose/gun on it.

first thing i found is the quick change tip/nozzle was rusted closed. cleared it up, started engine (started easy) and it actually started working, kind of.

engine idles fine at all speeds when not pulling the trigger on the gun. when you pull the trigger on the gun the engine and water output surge.

im not sure if i should focus on engine (carb), the hose/gun, the pump or other?

i cant find engine numbers, its an old briggs 3.8hp L head. craftsman number is attached.

 

[theoldwizard1]

That looks like a Briggs and Stratton "Quantum" engine.

A surging engine is almost always caused by a clogged (or partially clogged) low speed (primary) jet. Start by removing the gas tank and giving it a good rinse out. No sense in fiddling with the carb if there is crud in the tank.

The main (high speed) jet is the bowl nut on the bottom. Make sure it is clean. It is not easy to see/find the primary jet. Take a single strand of wire out of a wire brush and probe all of the small orifices. Then blow them out with carb cleaner.

Don't get carb cleaner on the bowl O-ring or it will swell. If it is swollen, was with soap and water and let dry for an hour or two. Be careful not to cut the O-ring when re-assembling.

 

[mopar4u]

Ok
Just wasnt sure cause with no load it doesnt surge. Ill focus on the carb first.

 

[nmantas]

Sounds like motor issues but those old oil-filled piston pumps fail with age/lubrication abuse/poor maintenance so don't be surprised if you get it working great and it doesn't last too long. I tried rebuilding a pump on one of those cheaper vertical power washers.....not at all worth it. Just buy a new bolt-on pump for less than $100. I got this one for $78 (AR is a name brand) but you can get generic for less.

https://www.amazon.com/gp/product/B0071CPCIA/?tag=atomicindus08-20

 

[Leaflessshadetree]

Mine sometimes does that when I first get started. Smooths out after a minute or so. I figure it's air bubbles in the hose leading to the compressor.

 

[nmantas]

Might just be that the governor is acting funky and slow to adjust to the load....besides some cleaning its probably not even worth investigating.

 

[mopar4u]

I know it has no value but i like to learn and fix. If a cleaning or zero dollar repair fixes it ill give it to someone for free.

 

[theoldwizard1]

Might just be that the governor is acting funky ...

DON'T MESS WITH THE GOVERNOR ! They are set correctly from the factory 99.999% of the time !!

 

[mopar4u]

i finally got around to tinkering with this old timer. i went through the carb, didnt appear bad. got out the carb cleaner, compressed air and metal bread tie for the cleaning.

no change, still surges under load. sometimes i could spray for a minute with no surging, release the trigger, pull the trigger and it started surging. sometimes constant surging.

i held the trigger and governor still for a bit and when it tried to surge it sure felt like the engine lost the load of the pump, ?air entering the system? there are no leaks from garden hose or gun hose. i am using small diameter garden hose, probably 3/8. the hose filter is clean.

when its working the pressure is good. could my hose diameter cause this? could something internal in the pump or gun cause this?

 

[Bert_]

DON'T MESS WITH THE GOVERNOR ! They are set correctly from the factory 99.999% of the time !!

Sure they might be set "correctly" but I've improved many small engine governor's with different springs or drilling different holes in the arm. Some small engine governors let the engine bog down quite a bit before the governor has much effect. I like to make them as sensitive as possible without causing issues. Keeps the RPM consistent until it truly runs out of power.

A well adjusted governor can make it seem like a whole new machine.

I agree that you should not mess with it unless you have a good understanding of how it works. A wrong adjustment can overspeed the engine.

 

[nmantas]

Sure they might be set "correctly" but I've improved many small engine governor's with different springs or drilling different holes in the arm. Some small engine governors let the engine bog down quite a bit before the governor has much effect. I like to make them as sensitive as possible without causing issues. Keeps the RPM consistent until it truly runs out of power.

A well adjusted governor can make it seem like a whole new machine.

I agree that you should not mess with it unless you have a good understanding of how it works. A wrong adjustment can overspeed the engine.

Or getting the part number and getting a replacement governor spring.....usually only a few bucks shipped on eBay. I would assume the spring steel is still fine since its not that old unless it is rusted which would change everything.