In article ,
Ignoramus17028 wrote:

http://igor.chudov.com/projects/powerwasher/

This is your tax dollars at work. I bought this powerwasher used from
the US military. I suspect that they wrote it off because the gas line
from the tank to the carburetor was rotten and leaking. Why else would
they write it off? If, say, the engine wore down and that was the
reason, the line would not be leaking. I replaced the line and the
engine started on the second pull. It is supposed to be a bad ass
power washer, up to 3,000 PSI, with the Briggs and Stratton 11 HP
Industrial/Commercial engine.

First Question: the engine goes faster and slower every 6 seconds or so,
maybe varying speed by 30%. Why would that be the case.

Second question: how would I regulate water pressure on this beast?
There is no obvious valve that I could touch. I think that 3,000 PSI
is serious pressure and I want to get some opinions before I start
messing with the pump. Maybe I should torque the nut on top of the
pump, shutting off bypass.

(Click on the thumbnail images to enlarge)

I only know the first answer:
If the air filter is clean...
Most likely is that the governor spring isn't firm enough, or is too
loose. Look around the engine's carb until you see the governor spring.
Might have to take off some shrouding and the air filter to get to it.
The tab that the spring hooks onto is usually bendable, but sometimes
has a lever with a clamping screw. However it adjusts, while running
the engine, move that anchor so that it stretches the spring a bit. If
the RPMs settle out, problem solved. If the hunting gets worse, go the
other direction with the anchor. That should do it.
If not, depends on what kind of governor you have--either air vane or
internal. You can ID the internal kind because you have linkage going
off to a small shaft poking out of the crankcase. The air vane type
will simply have a plastic flag next to the flywheel under the shroud.
Make sure the paddle can move freely on its shaft and isn't cracked.
Cracks respond well to JB Weld. If it's internal, it's somewhat
complicated to adjust and I don't want to write it all out if I don't
need to. (:
If it isn't your governor spring or linkage you'll likely need to
clean out the carb. First try running fresh gas in it--that'll take
care of about half the "bad" carbs out there. But I doubt it's a carb
problem since you didn't say anything about the exhaust and I don't see
any clouds in your photos. Normally if a carb is causing hunting
problems your engine will rev up, run rich, rev down, run lean, repeat.
That would cause nasty exhaust. I think.
Also, I saw in your photos that you're running it without any pull
starter cover in place. That starter clutch's (that little square shaft
poking out of the flywheel hub) plate holding the square stub shaft
usually is only retained by a slight friction fit and the pull cord
assembly sitting on top. It's not terribly likely, but running without
anything on top of it can let it come apart on you. Take a look and
make sire it's got something holding it on before you run it again.
Looks like the pull-start wheel thingamajig holds it, but I can't quite
tell from the photos.

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