Briggs 24HP surging, but only

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...after running for a few minutes.

At first start, fires right up, run like a champ. After about 5 minutes at full throttle (much less if you clutch the mower deck in; lots of load) it begins to surge. It eventually gets to the point that it stalls. I can fire it right back up, no problem but it will surge bad and stall out again very quickly; maybe 30 seconds or less and often backfires when it does.

Since it runs fine at first, its making me think its less a carb problem and more a fuel delivery problem. Like maybe I have a pinched line or the liner inside the fuel line has collapsed somewhere and is blocking fuel flow. I was thinking about running new line from the tank all the way up.
This motor also has the plastic "pulse" fuel pump connected to one of the valve covers. I was gonna take the line off and see if it squirts when I roll the motor over. Is that a good test?
 
Gas tank vent might not be working right, and after running awhile creates a slight vacuum and cuts fuel delivery? Try removing the gas tank cap and see if it makes a difference.
 
Originally Posted By: ZeeOSix
Gas tank vent might not be working right, and after running awhile creates a slight vacuum and cuts fuel delivery? Try removing the gas tank cap and see if it makes a difference.

Nope I topped off the tank while it was running and it made no difference.
 
You could have a fuel delivery problem like you say, but you could also have a fuel metering problem which is far more likely. Carburetors need clean fuel all the time. And since the passageways and channels inside a carburetor are so small, it doesn't take a very large particle do block the flow of fuel. We're talking microns. The symptom of surging is almost always caused by a fuel metering problem. We're talking nine times out of ten. Does the engine idle smooth out by setting the choke half way on?
 
Originally Posted By: das_peikko
You could have a fuel delivery problem like you say, but you could also have a fuel metering problem which is far more likely. Carburetors need clean fuel all the time. And since the passageways and channels inside a carburetor are so small, it doesn't take a very large particle do block the flow of fuel. We're talking microns. The symptom of surging is almost always caused by a fuel metering problem. We're talking nine times out of ten. Does the engine idle smooth out by setting the choke half way on?

Yes, but not for very long...

Originally Posted By: TheLawnRanger
https://www.youtube.com/watch?v=BFDO42XLtdU

Thank you!!! That sounds like my issue. This engine is at least 10 years old. Im sure my orings look like the ones in the video. Ill order the oring kit.
 
Last edited:
Originally Posted By: TheLawnRanger
https://www.youtube.com/watch?v=BFDO42XLtdU


All that cause E87 corn gas was left in the engine without stabilization. Carb and its bowl gooped up with varnish. Why its important to either drain or use a fuel stabilizer like Sta-bil. Or.. This is what Seafoam was actually created for. Use that year round. Or.. my fave Gumout Multi-Stytem Tune up. Which is a Seafoam/techron brew. That might be abble to clean things up just running it in the gas rather than tear the engine apart. While it could be an oring, my hunch is the cleanup that comes with the replacement has more to do with the fix than anything else.
 
Oh boy another meth fueled shakey camera disorganized repair video.

If people follow only one rule to make these videos better:
Video should always start with the machine completely assembled before repair.
Video should always end with the machine completely assembled and working.
 
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Originally Posted By: WyrTwister
Harbor Freight has green and black o-rings in kits .

Yeah but there is an odd shaped one. Looks like two "B"s molded together. I went to the place that was linked in the video, and in the ebay recommened was a whole carb rebuild kit, with all the orings plus gaskets, for the same price. No brainer.

Originally Posted By: LeakySeals
Originally Posted By: TheLawnRanger
https://www.youtube.com/watch?v=BFDO42XLtdU


All that cause E87 corn gas was left in the engine without stabilization. Carb and its bowl gooped up with varnish. Why its important to either drain or use a fuel stabilizer like Sta-bil. Or.. This is what Seafoam was actually created for. Use that year round. Or.. my fave Gumout Multi-Stytem Tune up. Which is a Seafoam/techron brew. That might be abble to clean things up just running it in the gas rather than tear the engine apart. While it could be an oring, my hunch is the cleanup that comes with the replacement has more to do with the fix than anything else.

Actually it had E0 in it.
smile.gif


Originally Posted By: mk378
Oh boy another meth fueled shakey camera disorganized repair video.

If people follow only one rule to make these videos better:
Video should always start with the machine completely assembled before repair.
Video should always end with the machine completely assembled and working.

Right? Maybe I should make a new one. Put my copy of Adobe Premier Pro to use.

Originally Posted By: dwendt44
How old is the fuel filter?

I have an oversized one give some restriction
after five years.

Fram G1.

One year.
 
To update. I bought the carb kit and tore the carb down. It was pristine inside. No goo or clogged jets. The fuel bowl had a hint of corrosion in the bottom but nothing else was effected.
However the fuel plunger oring was split and barely hanging on to the plunger. It was also smooshed on one part. I replaced all the orings and put the engine back together.
It ran great! For about 20 minutes then surged and died again.
I couldnt figure out why it ran great for so long, so I checked the fuel, as I had been running it for awhile to tune the engine governor to Briggs spec.
When I loosened the fuel cap, I got the sucking noise of a vacuum being released. So the cap had gone bad too. I left the fuel cap loose and had no more problems. I was able to complete a one hour 30 mow cycle with no further issues.
I ordered a new cap and that fixed the issue without risking fuel contaimination.
So I had two problems I guess. But the oring would starve it of fuel before it was able to put a vacuum on the tank enough that it couldnt pull fuel.
 
Last edited:
Originally Posted By: mk378
Oh boy another meth fueled shakey camera disorganized repair video.

If people follow only one rule to make these videos better:
Video should always start with the machine completely assembled before repair.
Video should always end with the machine completely assembled and working.


And I thought I was the only one that, that drove me crazy. Not everyone is cut out to be a YT star!!!
 
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