Pressure washer keeps stalling!

C

ceasler

New member
Hello,


I need help with my honda gx 390 engine. While pressure washing the engine runs fine for about an hour. Then it stalls out-first only every 20 minutes but it keeps on stalling out until it stalls out every 1-2 minutes. This, obviously makes it impossible to finish a pressure cleaning job. I had a general 4040ez pump on it(it was the pump that came with it). That pump was replaced recently by another general 4040ez pump (about 2 weeks ago). The pump motor ran fine for a few jobs until last week when it started doing what I described above. I just had the engine tuned up a month or two ago-new spark plug, air filter, oil changed regularly. I'm not sure why the engine is stalling out now-it didn't do it before I changed the pump. I again check the air fiilter, spark plug and made sure that the hoses had no kinks in them. I am really at a loss as to what could be the problem. The engine seems to run fine when its actually running!
I would really appreciate your help in finding out just what may be the problem is!

Thank you,

Chris
 
chris i hope the wiz looks in for you i think it every couple of days......i am having similar problems but i have changed nothing...i am going to put it for a service when i get chance.....my problem is if i keep a open gun(trigger pulled) on high pressure it runs ok as soon as i release it the p\w stalls.....if i twist onto low pressure it does not stall.

i was hoping the service would iron it out....
 
Chris check your eng oil, if its ok try to disconect the oil sensor it may be playing up.
 
Paul, yours sounds like an unloader problem. The outlet piston is most likely at fault. Remove the outlet fitting and you'll find a brass piston with an o ring on it and a spring. If the o ring is bad or gone, or if debris is keeping the piston from moving, the valve can't unload and acts like a regulator, overloading the pump because the cut off pressure is set too high. Chris, I agree with Robert, sounds like an oil issue, either low or a bad switch.
 
Russ,

I know the oil level is fine-I just changed it. Would the low pressure oil switch be the problem if the pressure washer runs fine for the first hour and then starts quitting every couple of minutes? If so, what how can I fix it? I'd prefer to have this safety feature working so the engine won't blow if there really is low oil, but I'd really like to have this machine running fine-I'm already behind on work! You can call me anytime: 828.279.3311. Thanks!

Chris
 
Hello,

The problem must have been the low oil shutoff switch. I ran the machine until it started stalling every minute. I then bypassed the low oil switch and it ran fine all day today. I ordered a new low oil sensor switch from the local honda dealer I was amazed that it was $67.00 for that little switch. Is this the regular price or does anyone know of a reputable person who sells parts like this? By the way, thanks again for the on-line diagnosis-once again this board proves invaluable!

Chris
 
No I didn't Russ. I guess this is something I also need to order. Actually, I could use some direction as far as installing the new switch-any advice?

Chris
 
You'll have to pull the pump and remove the side cover on the engine. Disconnect the yellow wire attached to the switch, remove the nut, unbolt the low oil sensor from inside the engine, and pull it out. Reverse the procedure to install it. Oops, step 1, drain the oil (he he). I always use Never Sieze on the crankshaft before installing a pump. Sometimes they're a real bitch to get off. Feel free to e mail me if you run into any snags.
 
Thanks for the advice! By the way, where can I get Never Sieze?

Chris
 
Anti-sieze can be purchased at most automotive parts stores.

One thing to keep in mind on the low oil pressure switch is if the machine is not setting level it will mimic this problem. Make sure the machine is reasonably level or the switch will read low oil and shut the machine down.

Bypassing the switch will not take care of this problem. You could experiance the same problem with a new switch installed.

Another thing we do is fill a measuring cup with the exact amount of fresh oil when doing changes. Guessing what is in a quart container can cause problems if you are wrong.
 
Hey, ceasler, one more point on the switch installation... make sure the piston is at top dead center to relieve valve spring tension. That way the camshaft won't want to move out of place. When I fill a Honda engine, I pull both oil caps and fill through one while watching the other. The oil comes to the top thread, and I'm done.
 
I have seen simular problems that had nothing to do with the Oil level.
It tried to kick my butt.
It was the fine plastic filter Hidden inside of the Plastic Barb on the bottom of the fuel tank.
It would run for a while then stop. Then run and stop. I tried everything. Finally I was going to clean out the fuel tank and there it was. Half plugged up.
 
Ron, it was the low oil shutoff switch gone bad. The oil level was fine and by bypassing the switch I was able to continue and complete the job. Thank you all for your help and expertise!
 
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