Runs good but presser drops soon after engage wand. gas unit.unloader valve apossible? 16 years oil .

The unloader valve is not opening soon enough to prevent water hammer from stopping the pump

Frank, either the unloader valve is out of adjustment(try loosening it off) or it is faulty and needs rebuilt or replaced as most people do.
Check the attached vids,instruction and guides, Good luck
"I hope this helped you out, if so let me know by pressing the helpful button. Check out some of my other posts if you need more tips and info."

Since you did not include a model number.. I have to speak in generic terms. On the output side of the pump there is a high pressure / unloader / bypass valve. There is probably corrosion on the stem of the unloader and the corrosion is causing the stem to stick in the brass stem guide. Remove the unloader valve assy from the output side of the pump. Clean off the corrosion with some scotch brite and the GREASE the stem. (Make sure the input water supply hose is connected but NOT on.) Dump about 2 oz of engine oil into the hole where you removed the unloader valve. Place a liberal amount of grease in the hole where the unloader was then install the unloader valve.

Start the unit but do NOT turn on the water for about 1 minute. Squeeze the power wand knowing full well your going to get oil and grease out of the end of the nozzle for about 45 seconds. Begin cycling the wand trigger rapidly.... multiple times. Your forcing the unloader valve to work.... Then try normal use.

I Not only work on these I have an Excell 2400 with the honda 5.5hp GX 160 engine that just this last weekend I had to do this exact procedure for the same reasons.... It is working like a champ again and it was new in 1997.

Thanks for choosing FixYa,
Kelly

The pressure unloader us usually the first part/s that fail. An unloader can fail resulting in no or very low pressure or good pressure, however will not unload when trigger is released and stall the motor. Look at breakdown for your pump and determine if unloader parts are available and reasonable. If too costly to replace these parts then install an ez start valve to help start engine and tie back wand handle to deal with unloader problem (workaround). Ez start valve can be seen here:
http://www.cmcpwe.com/accessorystartvalve.html

When not in use, store washer with oil in pump to displace the water. The oil will help lube internal parts and possibly cause the unloader to begin working (if stuck due to debris/rust). You can find a gizmo to help you feed oil into pump on ebay /other web locations. Good luck with your repair.

Hi and welcome to FixYa, I am Kelly.
Not sure if anyone has responded to you but.... This is a symptom of the unloader / bypass valve sticking. The unloader bypass valve is located on the output side of the pump either under a brass cap or an extended stem with a knob on it for pressure adjustment.
Try this...
- Lay the unit down so that the water supply connection fitting is facing up. Leave the high pressure hose connected with wand. (Power to the unit)

• First inspect the inlet screen for debris.
• Next pour about 3 oz of regular automotive engine oil in the water supply fitting. Take your time... do momentary on / off cycles of the switch (bump the pump.... on / off) You are trying to get oil to the outlet fitting (No more than 1 second on off cycles)
• Check for evidence of oil at outlet fitting
• Leave it set overnight with oil in the unit. (Water supply and outlet fittings up.)

NEXT DAY.... add 2 oz more oil and connect water supply. (PURGE HOSE of ALL air before connecting)

• Do not pull wand trigger yet
• Cycle unit on and off about 10 times slowly... don't ruin the switch then let sit 10 mins.
• Turn unit on without triggering and let run for about 2 minutes.
• NEXT STEP be advised your going to shoot out OIL
• Begin triggering the wand on 1 sec off 3 seconds for at least 2 minutes (your trying to get the unloader bypass spring / plunger and seals to start moving inside the pump high pressure area.)
• If your wand has a soap application function make sure the wand is in the HIGH PRESSURE position. (Closed CCW)

This procedure does not always work but, I have revived about 70 % of the pressure washers I worked on by just doing these steps. If the procedure does not work... you will have to disassemble the unloader / bypass valve by pulling it out of the housing and then cleaning up the inside of the pump housing and wiping the seals clean. IMPORTANT STEP here: Before inserting the valve back into the pump housing you MUST lubricate it with #105 white grease. Housing and unloader / bypass valve parts. (white grease in small tubes at any automotive parts source.

Thanks for choosing FixYa,
Kelly

Whar has happened is that your unloader / bypass valve is sticking. This is due to minor corrosion and having water in the unit over the winter. Most of the time they will sanp out it if you do the following:

Add 3 - 4 oz of oil into the water supply connection and briefly and I mean very briefly switch on the unit then right back off. Add more oil to the water supply connection and then let it sit overnight.

Then next day turn the unit on briefly and let it sit another 30 minutes. After this you connect all hoses making sure to purge the air our of the supply hose BEFORE you connect the to the unit. Then once you turn the unit on rapidly trim cycle the wand trigger. Your goal here is to cause a water hammer of the unloader / bypass valve to get the spring and cupped seal to move in the housing. Pause briefly and see if pressure builds then fan the wand trigger again. This can take a few minutes to get it to work but the routine of pausing waiting momentarily and rapidly tripping the wand trigger is what should get the unit going again.

If this does not work you will have to take the unit apart dis-assemble the unloader / bypass vavle on the output side of the pump and remove the corrosion on the spring and the housing.


Once your done cleaning up the bypass unloader valve before you put it back in the housing place a liberal amount of Lubriplate #105 White Grease on the spring and inside the housing on the mating surfaces. (#105 white grease is available at any Auto Parts store. It is in a 3 - 5 oz plastic tube)

Re-assemble the unloader / bypass valve an it should work like a champ.

Thanks for choosing FixYa.

Kelly

If you have pulsating usually you have at least one of the six check valves stuck open, so you're only running on two cylinders. You might have got some of your plumbers " grease" in the check valve. (Do you mean pipe dope?) three of the check valves shold be accessable from the outside of your pump but the other three are inside. You can get parts for your unit from www.pressure-washer-parts.com

Before you do the below steps check the water supply inlet screen for obstructions where the water hose connects to the unit. If you notice debris remove and clean the screen under running water with a small NYLON brush.

The bypass unloader valve is triggering earlier than it should. You can lubricate this by adding oil to the water supply inlet (at least 3 oz.) and very briefly switching the unit on then off 0.5 seconds. Then let is sit overnight. The next day connect power briefly and again cycle the unit on then off for 0.5 seconds. Connect the water supply and then purge the water wand hose into a bucket to catch the oil before use. After this restart the unit and operate the wand trigger under full pressure at 0.5 second intervals to ;scycle the bypass / unloader valve inside the pump. This method has worked in about 95\0 % of the machines I have worked on. The oil lubricates and fattens the seals in the bypass / unloader valve. It eihter works the first time or the seals are torn in the unloader valve and must be replaced. With only 3 uses I think your pretty much in the clear and will not need new seals.

Thanks for using FixYa.

Kelly

Hi Brian. Welcome to FixYa I am Kelly. This sounds as if the bypass / unloader valve is stuck in place and the pump id dead heading causing the unit to shut off. (There is most likely some corrosion in the unloader / bypassy valve assy / housing. What you can try is pouring at least 3 oz of oil into the water inlet assy and briefly.... like VERY briefly switch the unit on then back off. Then let it sit over night. The next day connect everything for normal use then turn the unit on again briefly. Use a bucket to PURGE the oil that you put through the system by squeezing the wand Power SW Off until the oil purges. Then switch the unit on and rapidly trip the trigger at 0.5 sec intervals or less. If it trips off wait 5 mins and try it again. Do the rapidly tripping the trigger on the wand routine for about 20 seconds. Your forcing the bypass unloader valve to cycle trying to clear out any debris / corrosion.
This works often and well. There are exceptions. Hopefully it will work for you.

Thanks for using FixYa.

Kelly

common for not starting unless trigger engaged as you are turning the pump as well as engine creating pressure,as for stalling pump has unloader valve which is probably in need of grease(use good silicone grease)this allows water to ciculate when trigger released.