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I have a 44u877-0005-g1 which was in tremendous shape 'cept blew connecting rod #1 - - low oil I guess. So the case was good so I bought a new crank, connecting rod, and 2 sets of new rings and installed. The heads/piston tops were a bit carboned up so I brushed off and cleaned around the valves. Seats looked good. Valve lash set - - Flywheel key good - - Started right up but surged. So, I took off the carb (these have the single barreled carbs that split off) and cleaned. . .runs quite a bit better . . but still kinda rough at speed. When I lower down to idle speeds, it surges. I'm still thinking carb but then see the ends of the exhaust pipes where it goes into the muffler are glowing red. . . . so it makes me think timing. I took off flywheel when doing the crank and installed new key. Valves are set. . . What else is there??? Thanks in advance all.

Check manifold for leaks

Sounds like you did a pretty good job on the rebuild - in my experience the timing on these small gas engines is not very tolerant, if they key is not showing any type of sheering it's in time - " unless you missed the cam gear tooth " mis matched with the crank but I seriously doubt it would run at all let alone as good as you describe. As to the exhaust being red - it probably always was but now you're paying it more attention. The surging at idle is not too uncommon I have one that does it all the time but goes away under load.

When it is surging apply some choke. If it smooths out then problem with idle circuit in the carb or air leak.

bertsmobile1 said:

Check manifold for leaks

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Thank you!!! I redid the heads with new gaskets . . but I'll check for leaks

Bertrrr said:

Sounds like you did a pretty good job on the rebuild - in my experience the timing on these small gas engines is not very tolerant, if they key is not showing any type of sheering it's in time - " unless you missed the cam gear tooth " mis matched with the crank but I seriously doubt it would run at all let alone as good as you describe. As to the exhaust being red - it probably always was but now you're paying it more attention. The surging at idle is not too uncommon I have one that does it all the time but goes away under load.

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Thanks for the reply. Yeah, I've rebuilt many mowers and if I was off a gear tooth, that will be my last resort to tear apart the engine again. Question for you . . have you ever changed out these V-Twins that have a single barrel carb for a double? I have one and was thinking of trying. . . The intake manifold looks the same and the linkages I believe would work . . .

Hammermechanicman said:

When it is surging apply some choke. If it smooths out then problem with idle circuit in the carb or air leak.

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That's a good idea - - I saw on a video that the cherry exhaust could be from not getting enough gas - - running too lean. Trying to put together all the symptoms. Carbed heads/pistons, cherry exhaust, runs rough at speed . .

I would imagine the machine is matched with a single Barrell carb for a reason / probably balanced for the exhaust ports etc.
Double carb might throw that off and cause you some heartburn but I'm only guessing.

Bertrrr said:

Sounds like you did a pretty good job on the rebuild - in my experience the timing on these small gas engines is not very tolerant, if they key is not showing any type of sheering it's in time - " unless you missed the cam gear tooth " mis matched with the crank but I seriously doubt it would run at all let alone as good as you describe. As to the exhaust being red - it probably always was but now you're paying it more attention. The surging at idle is not too uncommon I have one that does it all the time but goes away under load.

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My biggest fear. . skipping a cam tooth. . . and tearing the engine down again. Low and behold, after cleaning carb really well and having the same issues, I installed a new carb....and that was the issue. Starving for fuel somehow. my thanks

Yup, it was the carb . .bought a new one and it runs smooth. Thanks all

I had a Briggs V-twin last summer on a zero-turn that showed symptoms of BOTH running too lean AND running too rich. It acted too lean when it was cold and just started, but then behaved like it was choking to death after running for a few minutes. Drove me crazy. (There are some that say that ain't much of a drive.)

After tearing apart that split-manifold carb four times, I finally found the problem. It was a tiny shred of black rubber or plastic that had found a home in the seat of the float valve. It was about the size and shape of an eyelash. It was very insistent to stay where it was; I had to dislodge it with a dentist's pick, then clean the seat with a brass wire brush from a gun cleaning kit.

I have not heard from that customer since, which tells me that all is well.