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Riding Mower Loses Power Under Load/ Dies After 15 Minutes.


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07-22-14, 05:05 AM   #1  
Riding Mower Loses Power Under Load/ Dies After 15 Minutes.

I own a riding mower powered by a B&S engine (model: 31D707; Type: 0232 E1; Code 050128ZE).

The mower starts without issue (just replaced the starter solenoid) and immediately begins running in a manner that I can only describe as sounding like its timing is off. If I drive the mower, it runs okay (not great) for about 15 minutes, at which point it loses power as I take it uphill. Eventually it will stall. I can sometimes delay this by adding choke, but it's just enough of a delay to limp it back to the garage and avoid pushing it!

Here's the list of items I've addressed this season: changed oil, changed air filter, changed spark plug (twice), changed starter solenoid. I changed the spark plug just last week due to what (to me) appeared to be a large amount fo carbon on the plug I put in at the beginning of the season.

I confess that my level of experience/expertise with small engines is somewhere around "novice" at best...so please be patient with me! Any help or advice anyone can provide is greatly appreciated.

Thanks!

 
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07-22-14, 09:36 AM   #2  
Is it smoking when it runs? Does the oil smell like gas? Have you cleaned the carburetor?


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07-22-14, 12:28 PM   #3  
Cheese,

Thanks for the quick reply.

No smoke. Oil doesn't smell like gas to me... I haven't cleaned the carbureator, and am unsure as to hwo to go about doing so...to be frank, I'm a bit intimidated due to my lack of experience and knowledge, especially after reading some of the other posts in this forum. That said, I'll tackle anything...I just don't want to give myself an aneurism out of frustration.

 
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07-22-14, 04:43 PM   #4  
Have you tried running it with the gas cap loosened to rule out a gas tank venting problem?

 
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07-22-14, 07:40 PM   #5  
Eagle,

Yep...after reading the same suggestion in other threads, I tried that. No luck. 18 HP still ran like 3 or less.

I've looked at the B&S website, and between that and my parts diagrams for this engine, I'll try giving the carburetor a cleaning this weekend, sooner if possible.

Before I do that...any words of wisdom on what NOT to do in order to avoid catastrophic failure?

 
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07-22-14, 10:46 PM   #6  
It's a pretty simple affair. I don't think you'll encounter catastrophic failure assuming you aren't using a grinder and hammer to work on the carb. Once you take the bowl off, you'll see there just isn't much there. I wouldn't take it completely apart as in throttle plate and shaft and all that... just leave it on the engine and drop the bowl first to see if it has trash and/or water in it, give it a cleaning, and go from there. If it needs more cleaning, take it off.


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

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07-23-14, 07:03 PM   #7  
Okay, will do...thanks! I'll get back to you when I get this done, although it likely won't be until late Friday night or Saturday. This week is just plain packed.

 
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07-26-14, 02:54 PM   #8  
Well, Cheese, I didn't use a hammer or grinder...I promise. But I somehow screwed it up.

Got the thing taken apart, and there was all kinds of crud in the bowl. Cleaned/dried with carb cleaner and canned air.

After reading the B&S website articles on servicing/maintaining carburetors several times in an effort to not step on my crank, I removed the carburetor itself, but did not break it down completely, as per your recommendation...just sprayed it down with carb cleaner (again, lots of crud removed), blew it dry with the canned air, let it set a while to ensure all was dry, then re-installed. Felt pretty good at this point, as the only issue I'd encountered was a shortage of metric box wrenches...easily solved.

When I re-attached the fuel line, the thing proceeded to leak like a sieve. I can't even tell where the leak is coming from, it's so bad. I've tried re-tightening everything, and haven't noticed anything wrong with any seals.

Help, please.

Thanks,

Apache06

 
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07-26-14, 09:06 PM   #9  
Most likely the needle isn't seating in the seat. Check to be sure the float can hinge up and down, the needle is moving with it, etc..


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07-27-14, 05:06 AM   #10  
Maybe this will help. This guy gives a pretty good step by step description on cleaning that carb. I assume yours is a Walbro LMT carb. It should say LMT on the outside of it, if it is.

Disassembly, Cleaning and Repair of Walbro LMT Carburetor used on Briggs and Stratton Engines

 
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07-27-14, 05:25 PM   #11  
OptsyEagle,

As it turns out, the carburetor is actually a Nikki, not a Walbro, but I was able to find it on the website you provided...many thanks!

Cheese,

In the end, I don't know if it was the needle not seating correctly or not...but I was able to correct it after taking the carb apart and re-assembling it. The thing no longer leaks.

I fired the mower up and ran it for 90 minutes...got SOOO much lawn cut that was in dire need...and then it quit without warning.

So: power seems to be increased (I can drive it uphill now) and it doesn't quit under load. I directly attribute that to your advice to clean the carburetor out. I learned some stuff. Again, I directly attribute it to Cheese and the rest of the folks here that were willing to entertain my ignorance. Thanks, fellas!

Now...on to figuring out that new issue...

Apache06

 
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07-27-14, 08:53 PM   #12  
Good and bad news, huh? I'd start by checking for spark.


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07-28-14, 07:31 PM   #13  
Cheese,

Don't think spark is the issue. I monkeyed with some connections (specifically, the wires running into the fuel solenoid (I think that's right...the one on the bottom of the carburetor fuel bowl)). It was a bit loose, and I just pushed it in to ensure a good connection. Fired right up and I was able to finish cutting.

Now, I don't want to draw conclusions based off of one data point, and it's a simple matter of unplugging the solenoid to see if it cranks, but would a lack of connection there prevent it from starting? Is it worth a whole new solenoid, or do I just need to worry about that connection? As it stands, if that's what the (new) issue is, I can live with it for now.

Thanks again,

Apache06

 
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07-28-14, 07:51 PM   #14  
If the fuel solenoid is unplugged, it would kill the engine and cause it to not start. It shuts the main jet so that it can't pick up fuel.


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

God bless!

 
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