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Discussion Starter · #1 ·
This just started today. When mowing at full throttle, I can hear and feel the engine start to lag. It happens intermittently, with no special conditions. I have done a tune up (new spark plugs, air filter, oil change), and have replaced the spindles, pulleys, and blades. I have never rebuilt or replaced the carburetor or the fuel pump. This condition only lasts for a second.

Any ideas what could be causing this?

Thanks
 

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Discussion Starter · #3 ·
My bad, forgot to include that. Yes, while replacing the air filter and the oil.
 

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Discussion Starter · #4 ·
Any other ideas? The carburetor and fuel pump are OEM and have never been serviced or replaced. I also have never adjusted the values. Any of this could be an issue?
 

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it could be the governor needs adjusted... sometimes as parts wear they can become less responsive to changing loads on the engine.
this also appears to be a twin cylinder engine, so it may be an issue with one of the cylinders intermittently dropping out for some reason. it could be it needs a valve adjustment, but usually a related issue is more consistent..
Sounds like it would be a pain, but if you could get it on video doing that would help a lot. to hear it.
If you can, post the engine identification numbers, usually on Briggs and Stratton engines they are stamped into the valve covers.
 

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Discussion Starter · #6 ·
Thanks for the reply. The engine model number is 406777, type 0442B1. You're correct, it's a twin cylinder engine.
I just finished adjusting the valves. Only 1 felt out of adjustment.
If I may ask, where is the governor located?
Also, it seems to idle at a rather high rpm. Is this normal? When it warms up, and I don't engage the blades, throttle placement has no effect. In other words, once warmed up, moving the throttle lever up or down has no effect on engine speed. Engaging the blades will drop the rpms.

Thanks for the help!
 

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okay, there is an issue with the governor system.
I would check to be sure all linkage and springs are in place.

and if all linkages check out, i would adjust the governor
 

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Discussion Starter · #9 ·
Just FYI, I just finished adjusting the throttle cable, I sprayed everything down with carburetor cleaner, and lubed all the moving parts. I also set the governor as was shown in the videos. I don't believe the choke was closing all the way. Now it starts quickly, and idles at a much lower rpm. I don't know if this has completely solved the problem, but it sure runs better! Guess the real test will be when I mow again.
Thanks so much for your help!
 

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Discussion Starter · #10 ·
OK, now I've got a bigger problem. It's surging and backfiring. I've replaced the carburetor, replaced the spark plugs, and checked the gap on the armatures. It's now very difficult to start. I have to use ether to get it going.

Any ideas? I'm stumped. Pulling out what's left of my hair 😖😖😖
 

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Discussion Starter · #11 ·
Got it to run much better, but it doesn't want to start without the ether. I can see that the choke butterfly isn't closing completely. It's all operated by 1 cable. Maybe I hooked up the linkage wrong? I can't find anything on the internet about how to properly install the carb and hook up the linkage.
 

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Discussion Starter · #13 ·
Yeah, they're both there, I just can't see what's stopping the choke from closing completely.
 

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mmh, normally, it should have a screw to hold the choke plate in place, maybe it is too farm in, blocking the choke plate all the way, check for that, what I would do is to unscrew it just a little bit, and see if it is better
 

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Discussion Starter · #15 ·
The choke plate will move freely by hand, but when I hook it up to the lever on the governor, it hardly moves at all. That's why I was searching the internet for a video or any info on how to hook up the linkage, thinking that maybe I hooked it up incorrectly. I haven't found anything yet. Plenty of videos of how to adjust the choke on engines with a separate choke control, but nothing on the type I have. Bummer!!!
 

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Discussion Starter · #16 ·
OK, apparently the issue was caused by me. I had installed the choke linkage in the wrong hole on the choke lever, which was binding and keeping the choke from closing completely. I installed a new fuel pump for good measure. The battery was weak, so I recharged it. Now it starts right up and idles good.
 
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