Engine or pump?

S

scottwoodall

New member
New to the forum and hope I am posting in the correct place. I purchase a pressure washer from a friend of mine. It is around 1995-1997 model from a local pressure washer dealer, has a Honda GX340 engine and cat pump (4HP40G1). Guy never used it and has less than 10 hours on it. It was just to big for him and he ended up going to one of the big box stores and buying a small electric pressure washer. He had it serviced by the pressure washer dealer about 3-4 years ago and everything ran fine. So, it has been sitting up for forever. I get it home and start looking it over. The gas in the tank was so far gone it smelled like varnish and it was completely rusted out. Carb looked like someone put saltwater taffy in it. Buy a new tank and carb for it. During the dis-assembly process I inadvertently take the arm off the governor to more easily get a cable off. Put new tank and carb on, new fuel line and fresh gas and new spark plug. Give the rope a pull and it fires right up on the first pull. Only problem is that the engine is racing. Its probably going 5000 RPM. I immediately shut it off (ran for about 2-3 seconds) and realize I messed up the governor on it and it needs to be adjusted. I put a digital rpm gauge on it and get it down to 3400-3500 RPM. I forgot to mention there is also a throttle adjustment on the engine. When I made the gov adjustment I forgot about where the throttle was and it ended up being at about the halfway point when I made the gov adjustment. So, if I push the throttle all the way open it will go to about 4300 RPM. Anyway, I hook everything up to it to give it a full test run. Start it and set the throttle so the rpm is 3500, pull the trigger on the wand and the engine immediately bogs down. RPM drops way down when I pull the trigger. It still runs and pushes out water but the pressure is only about 1000 psi and the engine is probably only running at about 700-800 rpm. I let go of the trigger and ramp up the throttle to wide open. Engine is running at 4300 rpm and I pull the trigger, engine goes down a little but it is still running at around 2200 rpm and pressure is spot on at 3000 psi.

I did some pressure washing like this for a couple of hours and all worked well. I just never let go of the trigger so the engine wouldn't over rev. As soon as I let go of the trigger I would turn the engine off or adjust the throttle back down. Went to the dealer and told them whats going on. Also looked online. Everyone says it is the unloader. I buy a new one, stick it on, start it up and exact same things happens. If I have it running at the rated rpm of 3400, the engine just bogs down and pressure is around 1000psi. If I run the engine wide open at 4300 rpm, everything works fine (3000 psi). So, question is, is this an engine problem where it is not properly compensating for the load when I pull the trigger or is it a pump issue? I guess I can rebuild the pump (if I can find parts for a pump that old). I really cant afford to buy a new pump. I've already spent more than I would have like to. Attached are a couple of pics. Thanks for all of y'alls help. IMG_1233.jpgIMG_1234.jpgIMG_1236.jpg
 
Your governor is not set properly or the linkage is binding up. Here's how to set it...loosen the nut, take the governor arm and push it to the wide open throttle position. Rotate the shaft in the same direction until it stops, and tighten the nut. BTW, the engine is rated for 3,600 rpms, so you're pushing it a little too hard too.
 
You may need to reposition the spring after you reset the governor, if it still drops too many rpm. If there are different spring positions on that engine.
 
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