3416S stopped running

[JeffM]

Hi all, (I'm going to go into some detail because maybe you'll see something that I've missed.) I bought a 3416S last year (16hp B&S engine type 0127-01) after it had been sitting for a while. I rebuilt the carburetor, put in new points and condensor, new spark plug, new oil, fuel filter w/ shutoff. . . and it worked great. Started quickly, idled beautifully, responded quickly to throttle. Plenty of power. I took it for its maiden mow, and about midway through it suddenly started running erratically: no power, only ran at low idle. I had been going up a slight hill at the time and thought that maybe that had loosened up some crud in the fuel system: I chalked it up to a fouled carburetor. I limped back to the garage and forgot about it until now. Fast forward to the present. Tractor didn't start, so I cleaned the carb again and re-cleaned the essentially new points and plug, new gas, but that didn't help. Marvel Mystery Oil in the cylinder, a shot of starting fluid, and it turns over about three times and then dies. I think "fuel flow problem". I install a new carburetor and it starts right up. It runs a little rough, but I think that's due to my inexperience at adjusting carbs. I can't get it to run at full throttle, it backfires a few times, and it dies if I try to advance the throttle quickly, but at least it's running well enough to move. In its maiden mow for this year, the same thing happens: no power, only runs at low idle. Again, I have to limp back to the garage at low idle, and now it doesn't start at all. What gives? One thing I haven't checked is the timing. Can someone tell me how to check/adjust the timing on this? Also, I understand the flywheel key might need to be checked. How? Can I do this without removing the engine? I'd appreciate any help you could offer.

[RayS]

First off welcome to the club! Check the screen in the tank. I had the same symptoms last year. Break off the screen on the fitting that goes into the tank and put a inline filter on it. Thats what I did and haven`t had a problem since. If this isn`t your problem at least there will be no fuel restrictions in the tank. It could even be a weak magneto or a sheared flywheel key.

[UCD]

Check the fuel screen in the fuel tank, also the vent in the fuel tank cap. Another thing is gasket between carb and engine block bad creating a vacuum leak. To check this with engine running spray around carb base and other gaskets with carb cleaner, even a fine water mist will do. If engine smooths out/speeds up you have found vacuum leak

[JeffM]

As far as I can tell, there is no screen in the fuel tank; just a hole in the bottom where it becomes the angled fitting for the fuel line (the tank and fitting are a continuous piece of plastic).

[HubbardRA]

Check the torque on the cylinder head bolts. I had a problem with a push mower this last weekend. My son bent the crankshaft on my old mower engine. I picked up another old engine that was stored in my garage and put it on my push mower. Fired it up and started mowing, after a few minutes it started losing power and acting like it was getting hot. Found out that three of the head bolts were not tight. It ran allright till the engine started to warm up, then the head gasket started leaking badly. Fixed that, and it runs fine.

[RayS]

The screen is on the fitting that the fuel line is connected to. if there isn`t one then someone else has already removed it.

[tractor nut]

I would change over to standard 12v coil, I had what I thought were carb problems on a B/S on a B1, after the change it ran better than ever. There is a link on this site that shows you how to convert over to a external coil.:D Big Smile :D

[Ronald Hribar]

Did you have flywheel off? When installing flywheel or new key make sure that flywheel is tight Loose flywheels break keys.

[callwill]

can you post the link to the external coil switch please?!

[UCD]

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