Briggs engine on Toro recycler mower is possessed

[bwright1818]

I have the above mower. Not sure what model Briggs it is, but it has the automatic choke connected to the muffler, with a control rod. Symptoms vary. Sometimes it starts and runs. Sometimes it doesn't start. When it does run, it will sometimes go until I have to empty the bag, then it won't restart. Other times it runs for varying lengths of time, then begins to misfire, getting worse and worse until it quits....BUT, if it's in this mode, if I stop pushing the mower, it smooths out for awhile. It seemed to me like the coil was failing, so I found a used one on eBay for ten bucks. This SEEMED to work better for awhile, but then it started causing problems again. I had noted that there had been a number change on the coil, so I bought a brand new one for $32 from Partstree. This included a new stop wire, which I installed. It started and stopped as a test, about ten times, flawlessly. Then, when I went to actually mow with it, it wouldn't start at first, then started, ran well for a few minutes, then started misfiring randomly for awhile and quit, with the same condition as originally occurred, where it would run better for a while if I stopped pushing it. I should just throw this thing in the dump; but now, it's personal. Any ideas welcome.

 

[Rivets]

Sounds to me like you have a fuel or ignition problem. Will need to do a little troubleshooting to figure out which. This is what I would do if it came to me. Get yourself an inline spark tester and the next time you can’t get it started attach the tester and check to see if you have spark. If you have spark you probably have a fuel problem. If this is the case I suspect the float needle or seat has swelled and this will result in a lean starting and running condition. If you have no spark you have an ignition problem. When you replaced the coil did you set the air gap at .010”? Let us know what you find and post back with the model and serial numbers for the mower and we’ll tell you how to proceed.

 

[hlw49]

Check the kill wire where it goes into the kill terminal to make sure it is opening enough not cause this problem.

 

[Auto Doc's]

Pull the upper fan shroud, then operate the stop/go lever while watching the bracket at the flywheel brake where the cable attaches to it. The shut off switch is there also.

After years of use, the cable stretches slightly, and the cable retainer tends to give a little bit. All of this will randomly ground the cutoff switch at odd times.

 

[bwright1818]

Thanks guys. I find that much like some of the Yamaha outboard engines I have worked on, the spark is barely visible, even when it's there. On a Yamaha, you hear it more than you see it. I do have a spark checker and sometimes I see it, sometimes I don't...but when it's there, it is hair thin at best. Thus I am not really confident about whether there is spark or not. My wife can't pull it hard enough for me to get my face down near the checker. I DO suspect something with the shut off. I will look into that. Maybe I will run it with the stop wire off of the kill mechanism and see if it runs reliably. I am a big-time Lawnboy two-stroke fan, so yes, I have plastic 0.010" shim stock that I set the coil with.

 

[Rivets]

Please post model and serial numbers for the unit.

 

[Auto Doc's]

Hi Rivets,

If it like the one I have, the chassis model and serial numbers are hidden behind the rear deck flap where the bagger attaches. (Toro hid them)

"B",

The engine should have the stamped numbers in the valve cover, or they will be laser etched on the side of the block (opposite side from the carburetor)

 

[sgkent]

what Autodoc says could explain it, or running lean. Engines die when a load is put on them and they are too lean. The condition can be carb caused, air leak on a manifold especially if it has a plastic manifold that cracked, or a loose head.

 

[Rivets]

Hey Doc, I worked at Toro dealerships since the early 80’s and know where the unit numbers are located. Depending on model, there were at least 12 different engines used, depending on model and how old the model is. The engine numbers are located in one of 3 places. On the flap over the muffler, one the valve cover or laser etched into the side of the block. Without numbers we don’t know which engine he has and are only guessing the cause of the problem. Ball is in his court, we’ll see what he does.

 

[bwright1818]

Well, I feel like a bit of a dummy. I should have thought of this FIRST, but the way it misfired, it just sounded more definite on-off, than fuel. I ran it with the kill mechanism disconnected and it ran the same...bad to none. So, I figured it was fuel. I started taking off the carb. I removed the fuel tank, using a clamp on the hose to save the fuel. While holding it in my hand, I took the pinch clamp off....and not a single drop of gas came out. I mean not a drop. I loosed the cap and fuel came out as you would think it should. I put it all back together and ran it with the cap loose and it seemed to run well. I think this is some kind of fancy EPA cap, because there is no obvious vent hole in it. It doesn't seem like you can take it apart, either. I order a new cap, cheap enough. Has anybody ever tried to take one apart? I think the choke control rod wasn't bent quite right, either.