Small engine trouble

[JasonW]

Figured I’d post this here.

I have a pressure washer that’s recently started giving me trouble and wanted to see if anyone has any recommendations.

It’s a Generac 196cc pressure washer that has stated to shut off right after starting, usuall around 10-15 seconds after starting. Doesn’t matter if the wand is pressed or not. This model does not have a throttle.

I can keep it going by moving by closing the choke then opening it back. After it has ran 3-5 minutes it will stay running like normal. So it only does it cold(cold is relative as the issue started during the summer).

Things I have tried,
Problem still happens with the gas cap removed.
Air filter is good
Spark plug is good
Dissembled/cleaned the carb(spotless inside, no trash found)
Checked fuel like for obstruction.
Adjusted the coil clearance.
Ran it with a spark tester in place to verify it’s not losing spark while running.


Ran it today and messing with the choke about 3 times it kept running for over an hour I was using it without a hiccup.
It seems fuel related due to operational the choke to keep it going, although when it dies it’s like the on/off switch is switched. Have not checked the valves.

The pressure washer is almost 8 years old and always stored inside. Has always started on the 2nd pull if not the 1st pull.

Super long post but I try to cover everything at one go.

TLDR pressure washer shuts off randomly when cold, after 3-5 mins runs like normal.

 

[whatsupdoc]

"Dissembled/cleaned the carb "
Did you clean the main jet?

 

[JasonW]

"Dissembled/cleaned the carb "
Did you clean the main jet?

Yes I did.

 

[NCL4701]

Sounds like you’ve eliminated most of the usual suspects.

I’ve seen a handful of situations where the interior surface of the fuel line starts to degrade and release very tiny particles into the fuel as it flows to the carb. They can be so tiny they’ll flush through the jet but the engine may stumble or require some choke as they go through. Chances are they’re not big enough to see with the naked eye when it first starts. Usually has some relation to ethanol in gas, but not always. 8 years old… wouldn’t exactly be surprising.

I would change the fuel line. All of it. If it has a fuel filter, I’d change that, too.

I’d also drain all the gas out of the tank into a clear glass container like a big old pickle jar, let it settle overnight, and check it for sediment/dirt. If you see any sediment, the tank will need flushing, While the tank is empty, look in it to make sure there’s no junk/trash in it that could be intermittently blocking the outlet. Not incredibly common, but seen it a few times.

 

[Workerbee]

How good are you at cleaning carburetors? Not a snide remark, but Ive seen lots of DIY,ers that don’t really know what to look for. You very well be proficient but most aren’t. Did you remove the welch plugs so you could verify all the passages are clear? The tiny ports that feed fuel into the venturi as the throttle plates open can be plugged pretty easily. If you don’t care to pull and replace the welch plugs to check those ports, at least run a bread wrapper twisty into each hole. Then see how it runs.

 

[JasonW]

Sounds like you’ve eliminated most of the usual suspects.

I’ve seen a handful of situations where the interior surface of the fuel line starts to degrade and release very tiny particles into the fuel as it flows to the carb. They can be so tiny they’ll flush through the jet but the engine may stumble or require some choke as they go through. Chances are they’re not big enough to see with the naked eye when it first starts. Usually has some relation to ethanol in gas, but not always. 8 years old… wouldn’t exactly be surprising.

I would change the fuel line. All of it. If it has a fuel filter, I’d change that, too.

I’d also drain all the gas out of the tank into a clear glass container like a big old pickle jar, let it settle overnight, and check it for sediment/dirt. If you see any sediment, the tank will need flushing, While the tank is empty, look in it to make sure there’s no junk/trash in it that could be intermittently blocking the outlet. Not incredibly common, but seen it a few times.

Fuel drained out of it was clean. Tank is spotless, I did check the tank outlet. What’s odd it only does it “cold”. After it’s ran for a few minutes it will run as long as you want it to.

 

[JasonW]

How good are you at cleaning carburetors? Not a snide remark, but Ive seen lots of DIY,ers that don’t really know what to look for. You very well be proficient but most aren’t. Did you remove the welch plugs so you could verify all the passages are clear? The tiny ports that feed fuel into the venturi as the throttle plates open can be plugged pretty easily. If you don’t care to pull and replace the welch plugs to check those ports, at least run a bread wrapper twisty into each hole. Then see how it runs.

Not my first run at cleaning carbs. And it doesn’t cut off after it’s been ran a few minutes and usually if it’s fuel related any issues will continue then entire time the engine is running. Not sure if I’m overlooking anything.

 

[Flintknapper]

Does the engine have a Low Oil Shut Down switch?

Had to replace that on mine when it I could not find a 'fuel' related reason for it shutting down intermittently.

Just something to look at. My impression from what you've described (and tried) is that your issue is indeed fuel related. As mentioned by others, replacing the fuel lines would be wise, blow out the fuel tank well.

Aftermarket replacement carbs are inexpensive and work well enough....rather than cleaning/rebuilding the OEM.

 

[GreensvilleJay]

yes, quite possibly the low oil switch. test by removing the wire to it.
if engine runs fine, forever after that..it's a bad switch.

I disconnect them when putting new engines on rotottillers...

 

[JasonW]

Mine does not have a low oil shut down switch.

 

[mikester]

Not my first run at cleaning carbs. And it doesn’t cut off after it’s been ran a few minutes and usually if it’s fuel related any issues will continue then entire time the engine is running. Not sure if I’m overlooking anything.

My log splitter was acting up, would run fine then would suddenly stall for no reason. I was getting frustrated after cleaning the carb twice.

I bought a new spark plug, new air filter, and completely disassembled and cleaned the carb a third time - all jets, float bowl, all ports, etc. using a new carb cleaner without any added lubricants. Take the carb completely off and don't take any shortcuts. I dumped the gas and replaced it with fresh high octane. Splitter now works like new again. Also check your muffler for clogged spark arrestor screens. Check all your gaskets and float valve.

I've attached a good reference I found online for the Honda GC engines that might help you locate all the ports/vents/pilots/blah blah blah

Small gas engines really suck at times and ethanol gas and me leaving it in the tank doesn't help anything. The gas will crystallize in hidden spots and cause you grief. Be thorough and do it all again.

 

[PoTreeBoy]

My neighbor's pressure washer was acting similarly. I poured a healthy dose of Seafoam (more than recommended) in the tank. After running for about an hour, it has started and run like new.

 

[Oleracer]

Not loosing spark? No matter what its the carb …did you get the emulsion tube out and clean all the tiny holes. Newer carbs have passages that are almost impossible to clean. Try a ultrasound cleaner. Lately i just buy carbs for honda clones , stihl, Kawasaki others. Make sure valve lash is correct no valves hanging. But if it will run on choke its carb

 

[rc51stierhoff]

I don’t have much to add, but unless I missed it, did you try new fuel? (I saw it said the fuel drained was cleaned was it reused or replaced with fresh fuel?)

To me certainly sounds like fuel or fuel delivery issues unless it’s not consistently sparking. (No matter what I would check plugs and wires connect and air cleaner.)

Sure sounds like fuel or fuel delivery

 

[MOOTS]

Sorry, I had to.
Like others said, if adjusting choke helps, it’s carb problems. Maybe it’s just cold natured and need the choke on for a minute or so.

 

[JasonW]

Yes it was with new fresh gas. I will check the valves next. Not sure I will cough it up to being cold blooded as I’ve had it this long and this issue just came up.

If it’s fuel related why doesn’t it do it all the time? It starts normal, just cuts off after a few seconds. Only when it starts to shut off I will close the choke about halfway to keep it going. After a few minutes it runs like it should.

I could always buy a new carb for it but I’d like to determine the issue not by throwing parts at it. Id like to find the smoking gun on this.

 

[Workerbee]

Jason, fuel atomizes better when an engine is warmed up. Those ports I was referring to feed gas into the venturi when coming off idle and when your throttle plate is fully opened up they dont feed as much as when its barely open. If those are plugged up it could very well be not getting enough fuel to run from only the high speed jet, when your engine is cold and your governor is holding the throttle plate in the wide open position

 

[Oleracer]

Done many Honda and clone honda motors ( over100). The e tube i talked about sometimes doesn’t come out easy. So most never clean it. If you set valves go .001 intake 002 on exhaust it will start very easy. I have modified the crap out of these motors for kart racing. Buy a carb and mess with the oem one.
here is what e tube looks like. Those tiny holes have to be cleaned. Make sure you have no intake leaks.

 

[Flintknapper]

Its a pretty simple carburetor on those units.

IF the main jet and needle are clean, pop the top off of the fuel shut off lever and you'll probably find the rubber seal there is torn. Ethanol eats them up. It can partially block the flow of fuel to the carb.

Easiest fix for that is to just replace the carb with an inexpensive aftermarket one.

 

[GreensvilleJay]

Agree, spend $20 and replace the carb. You'll be 'up and running' in less than 1/2 hour.
The 'trick' is to run the engine 'dry', then DRAIN the fuel bowl if you're not going to use the machine for a month or more.

Spending 3-4 hours to properly clean a twenty buck carb is 'silly'.