Pressure washer flow "sputter"

I have a Landa 3500psi 4.7GPM Hot water machine and I’ve got about 33 hrs on it. It started doing some wierd stuff recently regarding the water flow. I took a short video of what’s happening but this program won’t let me upload it so I’ll try to describe best I can. I’ll start it up and with no wand or any attachment on it I’ll get this long straight flow of water. Then after about 30 seconds the flow will begin to widen out and start to choke a bit. So Im getting a sputter type flow. Anyone have any idea what could cause this? Thanks !!

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Did you ever resolve this problem? I’m having a similar problem with my machine. I found this reading some old threads about this same problem.

Check your water filters.

Thanks I’ll check it out!

Do you run a buffer tank

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I betcha his return hose is crimped to the buffer tank,creating the sputter,ask me how I know. Took me 2 days to figure that out. :joy:


I have a 200 gallon supply tank.

Filter is clean.

Supply hose is good. Could it be unloader problem?

To be honest I’m having the same problem, I thought it was my crimped return line, but no luck, then replaced the unloader with new one ,no change, it all started after I hooked it up to a buffer tank. It’s only a 4gpm hot machine @3500,I used to just hook to a spigot and let the bypass water run under the trailer. But I bought a 5.5 hot machine to run both @ the same time, so now I’m forced to a buffer tank. Anyways I’m having a sputter problem as well. It maybe sucking air some where. But my other 5.5 is running like a champ hooked to the same feed line and filter. So I doubt thats the problem, or maybe the 5.5 is robbing all the water from the 4gpm ? I have a 2" line off the buffer tank to a filter, then to a T, then to two 1 " lines feeding both machine’s

You’re starting both machines up with them throttled down to help both prime right?

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I leave around 50 to 100 gallons in at all times to avoid priming, but we did run the one I’m having sputter problems outta water the other day by mistake for a hot second because we were on a slight hill. Are you thinking air pocket in pump ? Is that possible after we ran it all day and the sputter never changed, and it’s also been doing that prior to the mistake.

I know this sounds simple but the tanks do have a good vent correct


I believe so,I have both returns just shoved in 2 separate holes I cut out and never siliconed yet. No sign of tank shrinking, its a cheap ole ibc thin tote.

One thing I’m watching is that the return from the 5.5 is whipping around in like a cracked crazed snake when off trigger, do ya’ll think that could be creating air bubbles and the 4 gpm is suffering for it ? The 5.5 is humming right along side it with none of these problems … I’m just spit balling and hoping to help me and @Dwg

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Have a throttle on the 4gpm honda 360 thats giving me grief, but no throttle on the 5.5 18hp vanguard. Its WO all the time. I’ll try the low throttle on the 4gpm tomorrow, but like I said ,it’s got water to it 24/7 because I don’t drain the tank. Thanks brother

Can you post a pic of what your set up looks like. Do you have good flow out of your tank.

Yeah, I’d always fire anything with an adjustable throttle up at about 1/3 throttle just to help prime. Sometimes an air pocket can form just before or right after the filter and be stuck there for a while. Yes, set your bypass hose up so it hits the wall of the tank and cascades down so there are no chances of air bubbles in the tank. I’d also check ALL of your hose clamps and barbs. You’d be amazed how often they work loose especially when you’re dragging your trailer over the conditions that you regularly drive.

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Don’t have one of my problem trailer, but I sure will take a pic at sun up.

This has caused issues for me before. Bypass lines were causing too much turbulence/air bubbles near the pw supply bulkhead fitting. Angled them to spray away from the supply fitting and it cleared it right up. I’ve also had thermal relief valves cause the same issue. The pump would run fine as long as it was hooked up to a force-fed source, like straight up to the spigot with no buffer, but would have no pressure when pulling off the buffer tank. Something about pump suction can cause them to leak. Just take it off and plug it if you have one. No need for it if you’re bypassing back to the tank, since it’s always circulating cold water.