Issues With Briggs 3.75HP Classic Mounted to Pressure Washer

[BigNutz]

So, I rebuilt this motor a year ago, didn't actually need much, but it was my first 4 cycle I had completely disassembled. It came off of a Monsoon pressure washer in which the pump had started leaking like a sieve and would have been more expensive to repair than replace. So I replaced it with a universal pump rated for 3.0 - 7.0 HP. Started using it all summer, and the thing worked like a charm. Per the pump manufacturer's recommendation, I flushed the pump with "Pump-Saver" after every use.

The last job I did with it was an all day affair, pressure washing the side of my house. It worked flawlessly, absolutely no issues. So now it's time to pressure wash the deck to prepare it for stain. So we get everything set up, brought the pressure washer up to the deck, hose ran, everything was cleared. Go to start it, and it starts right up. So I let it warm up, as I always do being careful not to let it run more than a minute or so without pulling the trigger. Here's where things go down hill. Every time I pulled the trigger and applied a load to the engine, it would stumble and eventually die. I could not keep the engine running with any amount of load on it. Here are some facts to take into consideration:

• The engine was never run without water being hooked up and turned on
• The oil was at a suitable level
• The gas was less than 30 days old
• I checked the coil with a spark tester and it passed
• I tried 2 different spark plugs and got the same result
• Pulled the air filter and ensured the governor linkage was moving freely, it was.
• In the second or two before it stalls, high pressure water, as one would expect comes out of the gun.

So I'm kind of at a loss. Here is what is in my head as far as possible issues, let me know your thoughts:

• The water source hose is run up from a story below, however pressure appears to be fine
• I am running an engine at the bottom of the pumps range, maybe it needs more power

Any help on this would be much appreciated!

Thanks,

BN

 

[Lawnranger]

Stumbling under a load is an indication of incorrect air/fuel ratio. The engine you have has a diaphragm & gasket between the fuel tank and carburetor. Many times all you have to do is replace both and clean the carburetor properly to get the engine running again.

This guy does a an O.K. job of showing how to replace the gasket/diaphragm and clean the carburetor. www.youtube.com/watch?v=lRWNq4qQ4ww

I usually pop out the main jet for inspection but if it is clean you don't have to.

 

[Rivets]

We have to figure out if it is a pump or engine problem. Hook up the hose, remove the pressure hose, turn on the water, start the engine. Does the water spray out the pressure outlet? Does the engine bog down? If the answers are YES and NO, we know that the engine and pump are functioning properly. Attach the pressure hose, but no gun, do you have high pressure out the hose and no loss of power from the engine? If YES, we put the gun back on and try again. If NO, we have a problem in the hose. Tell us what happens.

 

[BigNutz]

Awesome, I'll try both tomorrow and let you know. Gets dark early now!

 

[Rivets]

I may not be able to get back to you very fast, due to changes at work, I start eleven hour days tomorrow, but I'll try to reply ASAP when I get a chance.