Old mower rebuild - now what?

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  #1  
Old 06-03-06, 12:30 AM
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Old mower rebuild - now what?

This is a continuation of the saga began here:Old Briggs & Stratton blowing oil
It's an old old craftsman 19 with a B&S 6B-H engine. My son and I replaced the breather, piston rings, points and various parts on the carb. We cleaned the crud off the valves while we were in there.
So now we have it all buttoned up and repainted, shiny new hardware and everything. Gave it a belly full of 30 weight, a tank of gas, a good pull and nothing happened. A few adjustments later and we got a sputtering start with a VERY low idle as long as the choke was wide open. In fact, it was easy to start, but it would never get past putt-putt-putt-PUTT-putt for about 20 seconds and die. Gas leaking everywhere. Figured out the needle valve replacement was not closing properly and so I reinstalled the old one (this is the kind of carb on a 6B-H that has the needle right under the exhaust pipe... nice.) Now it doesn't start at all and every 3rd pull or so it kicks back taking the start rope out of my hand and leaving a pile of smoke in the air pipe (to adjust the idle screw I have to leave off the air cleaner, so now I can see down in there). I think that's bad. Any thoughts?
 
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  #2  
Old 06-03-06, 02:50 AM
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Sounds like a Shered flywheel key (I could be wrong).
My Craftsman 6.75HP mower did this I would pull it to start it And it kick back cost me $113 to have a shop fix it.
Did you remove the flywheel when you changed the points?
If so did you put it back on and tightin it down correctly? If not the flywheel could have came loose and shered the flywheel key causeing it to fire on the up stroke instead of the down stroke. (trust me I took my mower apart before giving in and having a shop fix it I did not have the right tools to remove the flywheel).
 
  #3  
Old 06-03-06, 02:27 PM
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Yes I did remove the flywheel. Darn thing wouldn't let me at the points without it. Sprang the 15 bucks plus shipping for a flywheel puller, sounds like I should have went for the wrench to go with it. Your assessment sounds logical. Like thats the only reason it woud fire on the wrong stroke, right? And subsequent kickbacks probably finished it off. OK I'll check. Also I wonder if I should reinstall all the old carb parts just as a test. Some of those new aluminum parts looked a tad different...
 
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Old 06-04-06, 04:03 AM
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The carb has NOTHING to do with the timing. The carbs job is to give the right mixture of fuel/air to the engine. The flywheel is the only thing that has to with timing as it tell the points and the sparkplug when to fire. If the flywheel is installed wrong or the flywheel key is sheerd it will cause the sparkplug to fire at the wrong time.I got the repair papers for my mower and I will list what they did as proof.
 
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Old 06-04-06, 12:43 PM
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Yes I would suspect the key as well, use a oem key!

You also did set the points to .20 right?
 
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Old 06-05-06, 11:19 PM
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Okay... We tore it apart and the key was not sheared. I don't know why the kickback. I wasn't saying you were wrong, just there were two things going on. At first it ran, but slowly. Then it started doing the kickback thing for no good reason at all. I suspected carb problems for the former and agreed with you about the latter. And yes I set the points to .20. Now that's solved we put it back together and went at the carb. Apparently the gasket they sold me partially covered the intake port and I didn't level the float when I stuck the new valve in there. Good thing I still had the old gasket around, nothing wrong with it, just it wasn't... new. Stuck it all back together and it fired up like a champ. A few adjustments to needle and idle and we have a wonderful little lawnmower. My son is tickled pink to be working in the yard with something his own hands helped to restore. Although I think I hear a bit of knock in there somewhere and we still need to solve the problem of gas leaking out the tank valve and carb drain, any suggestions besides get new packing for the tank valve?
 
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