Toro Recycler 20372 - random engine skipping, loss of power

Hi folks,

So I'm a bit puzzled by my Toro Recycler 20372. The last few mows, the mower runs great for the first 30-40 minutes. Towards the end of the mow, you can hear an obvious skipping / loss of power from the engine. It's very subtle, but definitely there. It seems to occasionally cause a "puff" sound as well. Again, almost indistinguishable from the normal engine sound, but definitely there.

It hasn't outright stalled yet at any point, but I definitely feel like it has gotten close. It doesn't seem to care about load vs. no load, but I think was able to nail down an increase in skipping when I would tilt the mower on an incline to go the other direction. That's not confirmed, but it seemed like it.

Anyway, steps I've taken to attempt to alleviate the problem:

1. Oil change. Checked the stick, looks good.
2. New air filter
3. New spark plug (SEE BELOW, hoping this isn't causing the issue)
4. Rebuilt / cleaned carb

After cleaning the carb, the issue seems less severe, but still present during the end of the mowing session.

Any thoughts? Could this be an engine malfunction? I'm not sure what would cause this to happen more often the longer the mower has been running. That doesn't really sound like a fuel delivery problem to me, but I could be wrong. I'm certainly no expert.

SPARK PLUG NOTE: I originally used the wrong plug when I changed it:



Eventually righted my wrong and replaced with the correct plug (longer threaded section):



Since mowing a few times, there is no carbon buildup on the end of the plug or other types of wear. It's gapped to the correct 0.30 specification.

Since you don't include the serial number for your unit, I'm assuming you have one with the Loncin engine. Spark plug on that engine is NKG number BPR6ES gapped at .028. I don't think that is your problem, but more of a fuel delivery problem. Here are a few things I would be checking. Trash floating around in the tank, when the level gets low it may settle over the out port, reducing the amount of fuel going to the carb. Tilting the mower will change the amount of fuel available in the carb bowl, but I don't know the angle or direction you are tilting it or for how Lang. You said you rebuilt the carb. These carbs are very touchy and float level and jet cleaning will change output, be careful when attempting to rebuild.

Sorry, the the engine is a Briggs.

That's a good idea regarding the fuel tank. There isn't a video guide online anywhere on how to take it off, but I'm sure I can manage with some tinkering. I'll have to wash it out and then let it completely dry. That might be the culprit and could explain the fact that it works fine for a little while.

EDIT: Removed the tank, clean it with water, shook it a few times with a full tank of hot water, etc. Put it back on, ran the carb dry, new fuel. We'll see how it goes next week.

That should not be a Briggs engine. It's a "Toro" ohv one. Sounds like crud on the carb bowl. I've seen several of these newer ones do this.

TobyU said:

That should not be a Briggs engine. It's a "Toro" ohv one. Sounds like crud on the carb bowl. I've seen several of these newer ones do this.

Click to expand...

Oh you're right. It's not a Briggs. I'm thinking of my riding mower. Sorry about that.