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tab a 05-24-2013 04:18 AM

Briggs large Flo-jet repair
The Toro rider (56170) I revived last summer is running really poorly this year. Using this link:

Disassembly, Cleaning and Repair of Briggs and Stratton Large One-piece Flo-jet Carb

I found that the float is nowhere close to parallel, so I suspect fixing that will make a big difference.

The other problem I found is what I would call a large amount of slop around the throttle shaft. After removing the throttle stop, I'd estimate maybe .015-.020" play? I guess there never was any replaceable seal here? Presumably this is a significant intake leak?


K-TRON 05-24-2013 09:23 AM

Those carburetors usually do not give the user that much trouble. When the engine is running do you hear an intake leak? Sometimes if the engine is muffled enough and you can get your ear or a mechanics stethoscope close enough to the questionable area you can find out where exactly the leak is coming from. Those carbs did not have anything other than a round rubber seal, which for the most part works well. If you really have 0.020" of slop in the throttle shaft, it may be time to drill the hole a little larger, and place a brass sleeve in its place. Before doing ANY of that, I would suggest putting some 90 or 140 weight gear oil in a squirt can and with the engine running, I would douse the exposed end of the throttle shaft. The thick oil will seal if a leak is present, and the engine will run fine. If the presence of the oil changes nothing, I would say that the problem you are having is coming from an improperly set and bent float, a possibly bad float seat, and or what you may have overlooked, an intake valve which is out of adjustment?

Good luck, and let us know what happens,


tab a 05-25-2013 09:53 AM

Before taking the carb off, and apart, I hadn't really suspected an intake leak--though I probably should have, given the way the throttle stop was 'jittering'. I was more concerned that I might have crud in the carb, either from breakdown of the original (?) fuel hose, or from gas left in it over the winter.

After getting it off, I found the poorly adjusted float, and noticed the large amount of play in the throttle shaft. Thought now might be the time to fix the play, if possible. Is there a part # for a brass or bronze bushing/sleeve for this, or a similar application, that will be the approx. size I'd need?

Thanks again.

K-TRON 05-26-2013 12:24 AM

I will have to check in my Briggs books, but I do not believe an oversized brass bushing was made for the throttle shaft. Usually the shaft or carburetor body was replaced. Parts are getting a bit harder to find for those old flo-jets, so sometimes you need to get a little crafty and machine some of your own parts. Drilling/reaming/pressing and installing a bushing is a good afternoons project if you have the skillset, and machinery. I will get back to you on whether a factory bushing or oversized seal was made or not,


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