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Discussion Starter · #1 · (Edited)
Hi I have owned this mower for two years and I live up North in Rochester, New York. I purchased it new and have done all the routine maintenance on it myself. The last couple of times I have used it I've experienced the power of the Briggs and Stratton 8.75 Hp Engine vayring from real strong to almost stalling while cutting the same heighth grass. I've checked the spark plug and it looks like its burning correctly. I also changed the air cleaner this year and the engine doesn't seem to run any better with the air cleaner completely off the engine. I think the carb needs to be cleaned and rebuilt. Can't believe it should have to be cleaned and rebuilt after running only two seasons. I have been adding Stabil ethanol treatment to my gasoline from day one. Could that have caused the carb to bog down??

Thanks in advance for any thoughts on what might cure this issue.

Leon
 

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The Sta-Bil is a good idea, and certainly didn't cause the problem. However, even with the treatment, it's not a good idea to leave gas in the mower during the off season. Do you drain the tank at the end of the season? The carb could be dirty due to varnish/gum buildup, which would be mitigated by a simple disassembly and cleaning. Trust me, with the Ethanol-laden gas we have in NY, I've had carbs get dirty in less time than yours! Also, when you checked the plug, did you check for proper spark? The spark should be bright blue. Always make sure to ground the plug to the head and hold it by the rubber boot!
 

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Discussion Starter · #3 ·
Until two years ago my previous lawnmower was a Honda and I had it for 14 years and the engine was still running good but the rear wheel drive wore out. I never had to do anything to that carb in the 14 years I owned it. I never had to drain the gas tank at the end of the season either, The reason I went with the John Deere was because it had electric start at a more reasonable price. Is the design of the carb on the Briggs and Stratton engine more prone to getting dirty? I noticed that there is no carb adjustment avaliable to the owner everything is set at the factory. The new lawnmower doesn't mulch the grass or leaves, as good as the Honda did either. I guess I'm a dissapointed with the John Deere JS 46 . I did see a bright blue spark when I checked it also. Thanks for the help.
 

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There's probably a whole lot of variables in the gasoline that went into your John Deere over the past couple of years compared to what you put into that Honda the 14 years before it that we will never know about. Yes, it would be a pretty good guess that the Briggs carb is apt to being more finicky, especially since like you said, there are no external adjustments. But then, I've found that some of the newer Honda carbs are less than anxious to run like their older ones did.
 

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:ditto: Yeah, your older Honda was made before a lot of the restrictive emissions requirements came along, many of which are detrimental to reliability. You probably need to clean the fuel system.
 

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Have you also checked the vent in the gas cap? If it's clogged up, it'll make your mower act like it doesn't want to run, to the point of shutting off, because a vacuum is created in the gas tank and the gas won't flow to the carb.
 

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Howdy…

Does the Engine sound or RPM change when ‘it’ loses power? Does the power loss occur after mowing 15 to 30 minutes? Do the mower blades slow or stop rotating? You may have a problem inside the hydro drive unit.

Good Luck.. Don S..
 
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