Need some help troubleshooting a gas pressure washer

[MJK]

Hi All,

I have a 10 year old Ridgid RD80704 Pressure Washer. 6.0HP Subaru Engine and a Cat Pump. I love this thing, and try to maintain it properly. So, it is current on oil changes, air filters, plugs, etc.

Today, while using it, it started running poorly and then died. After some fiddling around, I found that it would run fine if I disabled the idle down feature. So, I finished the job and then proceeded to poke around a little.

I don't know much about carburated small engines, but from what I can tell the throttle works fine when the idle down butterfly is open (disabled). When the idle down is engaged, the engine slows but sputters and dies.

I'm guessing it is running too rich due to a faulty idle down assembly? Before I drop $60 on a new one, can someone sanity check me here?

 

[Den69rs96]

I would just leave it disabled. I have a Subaru engine on my Ridgid 3000 psi pw. I have a manual throttle, but I pretty much leave it at full throttle except when I start it.

 

[MJK]

Thanks for the reply. That is the Plan B I was hoping not to use.

Doing that seems to work the motor a lot harder. When I shut it off yesterday, it was hotter and smelled of hard work in a way that it never has before. Trying to keep it happy so it lasts another 10 years.

 

[Jswain]

My guess would be the idle jet is plugged up with something, when it's running wide open the high speed jet feeds it fine, as soon as the throttle plate closes it starves for fuel due to blockage in the idle jet/circuit. Dismantle carburetor remove all jets / spray with brake clean then blow out with compressed air etc. If this scares you you could try the 1L of fresh gas/1 can of seafoam but if it's plugged then dismantle may be the only option

If you do try the seafoam treatment I would dump all current gas and put 1l of fresh non ethanol gas in it and 1 full can of seafoam, get it running and up to temp then keep cycling back from idle to full speed/try to keep it running

 

[MJK]

I'll give it a try, thank you!

 

[Den69rs96]

Side note cleaning those jets. The holes are very small and hard to see. You may need to get a metal brush and pull one of the strands off to poke through the holes.

 

[PiperCub49]

Have you been using non-ethanol? I would if you haven't been. It's called "marine gas" at the gas station. Not all have it. In any case, my first move would be to pull the carb apart and check it out. It's usually a very

 

[ovilla]

Side note cleaning those jets. The holes are very small and hard to see. You may need to get a metal brush and pull one of the strands off to poke through the holes.

If you need a smaller wire for cleaning out those holes, grab a bread wire tie and clean off the sticky paper part from it. The wire that’s left from it will be perfect for your needs.


Sent from my iPad using Tapatalk

 

[MJK]

Ethanol free is impossible to find around here, so I almost always ran the carb out of gas when shutting it down... until I got lazy recently. So, the idea that the idle control circuit is clogged somewhere makes a lot of sense.

I attempted to disassemble and clean the carb twice now. Used the wire in the idle and main jet passageways, cleared with compressed air, etc. It runs a little sweeter/smoother but the idle down still doesn't work. Whenever I enable the idle down switch, it simply sputters and dies.

Something I don't understand: It sputters and dies if I enable the idle down switch (hence closing the front butterfly) whether the PW is under load (trigger depressed) or not (trigger not depressed). I'm a little confused by this, as it previously only attempted to idle down if the trigger was NOT depressed.

I'm inclined to throw a new carb on it for $20 and see what happens, but I don't understand the behavior above.

Any ideas? What am I missing here?

 

[sberry]

Take it apart, blow out with aircomp.

 

[MJK]

Take it apart, blow out with aircomp.

Post edited to make that a little clearer. I did that - perhaps not well or correctly, but to the best of my ability.

The engine is a Subaru Robin SP170 / 170DT1130 and the carb appears to be a 277-62301-60 (pg 58 of the linked PDF).

The bowl fills up, the float works correctly.
The main jet seems to work fine
I did clean the pilot circuit with a wire and compressed air.
I must be missing something....

Edit: blue shows where I cleaned

 

[garfunkle24]

Does the bowl overflow from the vent if sat? I'm guessing needle and seat is worn or stuck open by something, overfeeding fuel which effects it more at low speed. Even if worn/stuck, might not overflow if fuel tank has a diaphragm valve controlling flow and not just a petcock.

 

[Jswain]

Soak the carb with jets removed and soak the jets as well in 99% iso overnight. Then spray through them all with carb/brake cleaner with the small hose attached thoroughly and then finally blow out with air and reassemble. Inspect all gaskets as well because if it's sucking air and making it too lean to run with fuel from the idle circuit but with the additional fuel from the high speed circuit could make it run perhaps. Check spark plug and post a picture / clean or replace

 

[MJK]

The gaskets are OK and seal well. I don't think the bowl is overfilling. The engine definitely runs better at higher RPMs than lower - even when leaving the idle down butterfly open and manually adjusting the throttle linkage.

The main jet did NOT want to come out, so if there is an issue in the seat then I'm not at all confident I can get in there. Still not sure why the idle down behaves the way it does, but for $20 I am going to try a replacement carb, check the plug and see what happens.

Will let you know how it goes.

Edit 1: New carb is installed, and it runs much better. Idle down still doesn't work, but I can now tell is IS sensing the load. I need to adjust the 'under load' rpm up a bit and the idle down a lot but that now seems solvable. Thanks to all who helped!

Edit 2: After much mucking around, it finally does what it is supposed to do. It is amazing the amount of stuff that needs to be 'just right' for this to work properly. Idle jet needed a lot of leaning. The throttle close stop needed opening a bit. The bypass valve got cleaned. Pressure sender cable needed tensioned. The load adjustment linkage/rods/springs needed cleaned/tightened/lubed. If this lasts me another 10 years, I'll be happy and going 220v next time.

If anyone finds this in the future, I used a Venseri 277-62301-30 Carb off Amazon.

Thanks again to all who helped.