No spark on gas pressure washer

[ps2cho]

So I have a Yamaha MA190 gas pressure washer I got from Costco a few years ago.

Only used it 4/5 times. Come to use it last week and it won’t run. I’ve pulled the carb bowl, no signs of gummed up, jets are clean and clear. Fresh gas in it...

I pulled the spark plug, turned the motor over and I don’t see any spark at all. I swapped the spark plug itself and still no spark...I have it set to choke, there’s no other on/off button. I don’t think I’m doing anything else wrong...

I’m new to these small engines...how can I find out what part went bad for the spark?

Seems crazy to me something’s failed already - I have probably 3hrs life on the engine! Stored in the garage...really odd.

 

[classic70]

Check oil level, some small engine have a low oil level shutdown. Other than verifying that the kill switch is not on. May have to look into coil if both of those check out.

 

[wtn1271]

How do you shut it off once it is running? They usually have on On/Off switch somewhere. I'd check switch position, connections, & wires going to and from the switch. If no switch exists, then check spark plug wire and magneto/coil. Sometimes mice like to build a nest under the recoil shroud and they will chew the wires.

 

[Chucktin]

No spark at the plug means either the plug is not grounded well enough or not getting any "juice" (DC from the coil/magneto).
Make certain the plug is well grounded and try again. If still no spark trace the plug wire back and look for bare wires (rodent gnawing maybe) or loose connections.

 

[SARG]

Every power washer I've seen has a switch.

 

[ps2cho]

How do you shut it off once it is running? They usually have on On/Off switch somewhere. I'd check switch position, connections, & wires going to and from the switch. If no switch exists, then check spark plug wire and magneto/coil. Sometimes mice like to build a nest under the recoil shroud and they will chew the wires.

It has an OFF / CHOKE / RUN toggle. I have it set to CHOKE when testing the spark plug.

I can smell the gas coming out of the open spark plug port when turning it over, so I know fuel is going in. Its missing spark.

 

[DFB]

Change the plug

 

[SARG]

As DFB said .... bad plug or bad switch. I'd jump the switch with a bypass wire.
And that's gotta be a type of switch unlike any I've seen....... Carb setting controlled by an electrical switch ? Are you sure it's the on/off or just the carb control ? ( If you don't see wires it's the carb control )

 

[jacked_72]

I think kill switches are generally grounded to kill the spark. You might trying unplugging the leads to the kill switch and see what you get. Other than that, it is probably the coil or a bad plug. Check out some videos for checking resistance of the windings.

 

[wtn1271]

Possible to get a picture of the control? Are there any wires/contact point near the off position? Should be something there to ground/kill the spark. If your feeling frisky, you can hold onto the spark plug wire while pulling the motor over, with spark plug out, you will quickly know if your coil/magneto is working. Sound like a ground issue to me.
Searched google images for that model but nothing shows engine up close.

 

[JRC3]

So was the spark plug grounded when it was tested, as Chucktin said?

 

[CoogarXR]

Check oil level, some small engine have a low oil level shutdown. Other than verifying that the kill switch is not on. May have to look into coil if both of those check out.

I bought a cheap non-running generator at a yard sale and this was the problem with it. The low-oil-level sensor was bad. It was full of oil but the sensor knocked out the spark anyway. I just disconnected it for now. I'm sure someday* I will replace it.

*probably not.

 

[RTM]

I am in the grounding camp. My engines have a ground wire attached to the throttle, so when you push the throttle to off, it either grounds or opens the circuit (forget which). I'd guess opens to stop on yours, and something damaged a wire to the ground, rodent or accidental contact.

And yes, the plug must be grounded to the block to get a spark when its out of the head. Usually double insulated pliers are the trick, or you get a nasty jolt.

 

[killer cougar]

Got to ask the same question as Chucktin and JRC3, was the plug grounded when you tried viewing the spark? It won't spark at all unless its grounded to the engine body. You can either hold the spark plug against the engine and pull or get an inline spark plug tester but either way the plug itself has to be grounded.

 

[Keyblazer]

I took the pressure washer home, to try to fix it(I'm Dad)..
Confirm no spark when plug out and grounded against head!
Let me post a couple of pics...
I confirm that there is a 3 position ELECTRONIC switch... Off, Start, and Run.
There is a limit switch under that, that basically has 2 positions...
On and Off.
There are 3 wires attached to the switch
1/ Green/Yellow(wire goes to valve cover attachment nut, so GROUND).
2/ Black wire(Goes to Coil).
3/ Green wire(Goes to starter switch).

When the Manual switch is in the off position, the switch is activated, and I get continuity between Ground wire and

 

[jbfsr]

What is that black on the yellow wire connector? Burnt? if burnt, replace the connector.

 

[dogdog]

1) buy one of those inline testers if you didn't have one, HF price is $4 or Lisle one for $10 or any thing in between, cheap works fine. you should see the neon light flickering as you pull the cord regardless of the engine running or not.

2) check your gap on the magneto. usually it's about the thickness of a business card if you don't have a feeler gauge or check the manual for the gap size.

3) check your off switch. most small engine when they say off, it really means the non-ground lead on the magneto output is grounded so it will no longer produce spark. (ground means the switch is on) when on or start, the switch is really off most of the time.)

rarely the magnet is damaged but there are times heavy rust form that might mess with the magnetic flux.. clean it if you see lots of shaving accumulating.

I think that is about all on sparks with small engines.

 

[2ndGearRubber]

What is that black on the yellow wire connector? Burnt? if burnt, replace the connector.

And probably the component it is connected to.

 

[gmcgeo]

So I have a Yamaha MA190 gas pressure washer I got from Costco a few years ago.

Only used it 4/5 times. Come to use it last week and it won’t run. I’ve pulled the carb bowl, no signs of gummed up, jets are clean and clear. Fresh gas in it...

I pulled the spark plug, turned the motor over and I don’t see any spark at all. I swapped the spark plug itself and still no spark...I have it set to choke, there’s no other on/off button. I don’t think I’m doing anything else wrong...

I’m new to these small engines...how can I find out what part went bad for the spark?

Seems crazy to me something’s failed already - I have probably 3hrs life on the engine! Stored in the garage...really odd.

What was the process for checking for spark? how did you check? ground it? or just pull it out and see if it sparked?

 

[Keyblazer]

Black mark on that connector is actually a sharpie mark… was already there, but we’ll spotted!

 

[FrankieD]

I have a Generac pressure washer. The only way it will start is if the water hose is connected
and turned on. No water pressure no start. There's a pressure switch on the inlet side to protect the pump from dry starts.