Prochem Performer 405 eratic RPM at high speed??

Can't figure this one out. Replaced plugs, fuel pump, fuel filter, change blower belts, alternator belt, governor belt.


When at high speed AND under a load (150' hose connected) I'm getting erratic RPM/idle problems.. It almost sounds as if the unit is having trouble keeping up with the demand from the blower or even not getting constant fuel. It's NOT too bad, but it is noticeable. What's even more weird is that when I pull the vac hose off the high speed RPM becomes constant again. Also, it's only occurring approx. 25% of the time.. I'll be cleaning and notice it happen in long spurts. I do not have any problems at the lower RPM setting/tooth (I believe 1900?)..

Any advice would be great!!

Brand new belts everywhere.. Don't think it's the blower belts unless they're not tensioned good enough but they feel tight to me.

Yes oil in governor is good.

I noticed the belt on the air pump was real loose so I tightened it up and haven't noticed the problem after running for about 15 minutes..

I'll have to do more testing to confirm the fix.

By the way, how do i clean the carburetor? I replaced the air filter in that round thing, is that the carburetor?

So it may be the carburetor that's affecting my idle?? Where on earth am I going to find a new-used one? Should I just search for Nissan engine carb on ebay? I can't simply call the Nissan dealer for a part # because they want to know what car it's from.

By the way, i did a whole job and did not noticed the problem, but I'm sure it will be back.

Ok problem is back but I am noticing the bogging getting really bad when my waste tank is almost full.. So what relay are you referring to replacing?

So the carbureter has the fuel jets inside it?

Got it, I'll look for it now.

I believe I replaced the right relay. It was less than 6 inches away from the oil switch connectors just behind the cover. Impossible to unscrew without a really short screw driver. I just bought a new one and plugged it in still hanging.

Hopefully that will get me going.

Ok after replacing oil relay I still have the same symptoms, INTERMITTENT engine bogging then a random shut down about 45-60 minutes into cleaning. The engine will start again but seems hard to start everytime it shuts down. I can then clean for another 45 minutes or so before another shut down.. Not sure if this is related but I empty the waste tank before restarting because it looks to be only inches away from touching the waste tank float switch.

Other problems that I've observed that may or may not be related are:
-My low water pressure switch could be out because I have ran out of water a few times in the past and the machine kept running.
-I can hear lifter noise at low idle, probably going to need to be adjusted.
-When engage my heater exchanger within the first 15 minutes of the machine running the engine will die. Even if I use my bypass switch to engage it.
-The waste tank typically never gets full enough to shut the machine down before it shuts down on it's own.