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I have a Yard Man Model 449 self-propelled mower with a Briggs & Stratton 125K02-0281-E1 engine. For much of this grass cutting season, the engine has been surging to a small extent, but it had recently begun getting worse.

Now, though, the engine won't start at all.

What I've done so far:
-Replaced the spark plug
-Replaced the air filter
-Drained the fuel tank and replaced with fresh fuel
-Checked the oil
-Cleaned the carburetor bowl and nozzle and checked the float for proper operation (I replaced the carburetor a couple of years ago)

None of these things have resulted in any change.

I currently have the ignition coil off to test it. However, I have a question about testing. I have an older multimeter that only has x1k and x10 ohm settings. All of the videos I've found for testing an ignition coil indicate that you should use a 20k setting. Currently, when I test the ignition coil at the 1k and 10 settings, I get a reading of just a little over 2. Since I'm getting a reading in this range, does this indicate the ignition coil is good, even though I'm not using the 20k setting?

If the ignition coil is not the problem, another potential issue I've noticed is that the choke lever is not fully closed when the engine is cold. The governor lever can move to a position that would close the choke lever, but its default position has the choke lever maybe half-closed. Is this normal operation for this engine, or does this indicate a problem?

From what I've written so far, is one of the two issues I listed above the likely culprit, or is there something else at play?

If you need any further information, please let me know. I'm definitely inexperienced when it comes to small engine repair, so I don't know exactly what's helpful to include. Thanks in advance for any assistance.

That's not the choke lever, that is your throttle connected to the governor link and spring. It won't be wide open unless the motor is running and put under load, or sometimes at rest engines will sit with the governor open.
You can't test ignition coils with meters due to the internal triggering components, easiest is just to use a spark tester, or spray fluid into the plug hole, reinstall the plug and wire and try to start.

Surging is caused by a lean fuel mix ratio, meaning there is either TOO MUCH AIR in the mixture or NOT ENOUGH FUEL in the mixture.... This could be the result of a leaking carburetor/intake gasket or even a cracked intake pipe (manifold)
Also for clarification you cleaned the three holes in the bowl nut, and the nozzle it leads to?

Thank you for getting back to me. I appreciate it.

Just to clarify, the part I'm referring to that is open when the engine is cold is the small flap or shutter that sits in the large intake valve in the carburetor. Is that the throttle? I just wanted to make sure we're on the same page and talking about the same part. If so, it's okay for that component to be in a partially open position when the engine is cold?

I will try to get my hands on a spark plug tester and go that route - thanks for the suggestion.

Yes, I cleaned the three holes in the bowl nut and the nozzle. After cleaning, I used compressed air to make sure there were no blockages.

If you have a primer bulb, you don't have a choke.... went out and looked at my 2 same engines, yes they sit open a bit........ Could be the plastic intake pipe could be cracked, thats the tube next to the flywheel that goes across the top of the engine/

This is really helpful.

Come to think of it, when I had the carburetor off the other day, I did notice there was a small crack in the intake pipe right where it meets the carburetor. I didn't think much of it, but it was definitely a decent-sized crack.

jolo1011 said:

This is really helpful.

Come to think of it, when I had the carburetor off the other day, I did notice there was a small crack in the intake pipe right where it meets the carburetor. I didn't think much of it, but it was definitely a decent-sized crack.

Click to expand...

Then that's likely what caused your surging, and eventually no start... I've replaced a few.

Thank you! I will go in that direction.

Here's the part number for the intake manifold

Thank you! It's ordered and on the way.

jolo1011 said:

Thank you! It's ordered and on the way.

Click to expand...

Did you inspect it and find a defect?

I got the new intake manifold installed and got everything put back together. Started up on the 2nd pull. Now, it's working too well. The RPMs sound way too high. I've adjusted the throttle a little, but haven't really noticed much difference. Is there another way to make a bigger change to the engine speed?

Did you inspect it and find a defect?

Click to expand...

Yes, the end near the carburetor was heavily cracked and I think part of it may have been missing. The new one fit perfectly and seemed to fix the original problem.

Did you adjust it by lessening the tension on the governor spring?
you may need to bend the metal tab the spring hooks too

I finally got a chance to adjust the governor spring some more. The tab that the spring hooks to is back far enough that the spring is totally slack. However, the RPMs still seem too high. Is there another part that could be out of whack that's causing this condition?