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2-year-old Toro Lawn Mower Engine struggling


boster's Avatar
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06-06-14, 02:20 PM   #1  
2-year-old Toro Lawn Mower Engine struggling

[I don't have much model information. I'm happy to provide it, but I'm not sure where to find it. The marketed model of mower is Personal Pace. It's about 2 years old. There is a label on the engine, but turns out that just provides a serial number or something of the sort. If someone can tell me where I'll find the make and model of engine I will happily provide it.]

Recently (last couple weeks) the engine has begun to sputter, getting worse and worse until today it stopped. The exhaust is dark, as if it's burning oil. When it runs it's low speed and has little power for cutting grass.

My son told me it was getting bad, and the first time I experienced it it was really struggling. I had a few thoughts about possible causes:

CHOKE
I thought maybe the choke was stuck or left on. But then I couldn't find a choke on it at all.

FILTER
The choke idea led me to wonder if the filter was clogged and the engine could not get oxygen. I took off the filter cap and oil was collected at the bottom of the filter housing. The filter itself looked okay.

OIL
I wondered if oil was somehow seeming into the fuel. I don't know how to check this. I did note, though, that it has oil. There's no sign that the oil is depleted.

FUEL
I wondered if my son or I had made the mistake of giving it a fuel/oil mix. When the fuel tank was about half empty, I gave it what I new was good, clean gasoline, with the thought that any oil concentration in the fuel would be cut in half and the engine might do better. In the driveway I ran it for a few minutes, and then the engine did improve a little bit, enough that it made me hopeful that I'd found the issue. But when I put the mower in the grass it went back to struggling and gasping. Before long, the fuel tank was half empty again and I again added clean gasoline. No more improvement, though.

Another observation: My son unscrewed the oil cap/dipstick while the engine was running. We found that the engine ran faster and seemingly better when the oil cap/dipstick was unscrewed than when it was fastened tight.

Another observation: It seems to be burning through fuel pretty quickly.

I'm handy with a screw driver, and I understand mechanical concepts pretty well, but I have little experience with small engines. Any help you all can provide would be much appreciated.

-boster

 
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06-06-14, 05:31 PM   #2  
I'd suspect a carburetion issue, but I can't give any info without something to go on. I don't know if this is a riding mower or push mower or if it has electronic controls or what kind of engine is on it. Did you try running it without the air filter? Does the oil smell like gas?


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

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06-07-14, 11:37 AM   #3  
Thanks, cheese, for the quick response.

This is a self-propelled walk-behind mower. No electronic controls. I've taken the plastic cover off the engine and looked for a manufacturer and model, but so far have not found it.

I believe it is a four-stroke engine. Straight gas, not a gas/oil mix.

The oil does smell like gas.

I took the air filter cover off, and removed the air filter. This did not seem to improve the performance. In fact, now I have trouble getting the engine started at all.

Does any of this help point toward a problem, or at least narrow down the list of possibilities?

-boster

 
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06-07-14, 07:39 PM   #4  
The smell of gas in the oil usually means the carburetor has been leaking at the needle and seat. I'd suggest cleaning the carb, clean and or replace the needle and seat, and possibly the float if it has gas in it. Change the oil, and try again.


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06-08-14, 11:44 AM   #5  
Thank you, cheese. I will give that a try in the next couple days.

-boster

 
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06-19-14, 09:03 AM   #6  
Solved

I ended up cleaning the carburetor, because tracking down parts wasn't as easy as I'd thought it would be. I found a couple clogged holes in various parts of the carburetor and got them cleaned out.

Then I ran more tests with the filter in and the filter out. I found a big difference in how it ran. Replaced the filter and now it's running great.

In hindsight, I think the carburetor wasn't letting gas flow like it should. I know gas and/or oil were getting into the filter housing; the filter ended up soaked in gas/oil, and wouldn't let much air through.

cheese, thank you for your help.

-boster

 
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