Manda 0 #1 Posted June 6, 2013 We have a 1975 B-100 that is in overall really good condition. This winter we used it for plowing and it was running great. Then the alternator quit working which apparently is a rectifier issue? So we quit using it so we could wait til warmer weather for my husband to fiddle with it. Come Spring he went to fiddle and found it had a hard time turning on at all. Many hours later, it turns on and all but its running REALLY rough. Lots of sputtering and rough running. My husband has cleaned the carb and its fine, fuel pump appears to be working fine. He actually took the rectifier off and its running off the battery and that worked fine for awhile and still ran smooth so he doesn't think that is the problem. He has looked it all over and cannot for the life of him figure it out.. Its new gas.. He just replaced head gaskets on the Kohler engine.. He replaced the spark plug. He is out of ideas, can someone help him? Again, it runs on an idle and freaks out higher and runs badly.. I can make the mower turn but its doing a poor job of cutting. I cannot tell if it is a fuel thing or a power thing... and my lawn is becoming a jungle! help! Share this post Link to post Share on other sites
Manda 0 #2 Posted June 6, 2013 OKay now when its cold its running okay and idle is okay.. turn it up specially as it gets warm, it sputters and sputters... and a bit of trouble trying to go uphill. It acts most like a fuel problem as the spark plug keeps fouling up and when you first turn it on, black smoke comes out the side (unburned fuel) i made Hubby turn it on for me so I would at least halfway sound like I knew what i was talking about! LOL Share this post Link to post Share on other sites
WH nut 553 #3 Posted June 7, 2013 Has he adjusted the Carb.? Share this post Link to post Share on other sites
Manda 0 #4 Posted June 7, 2013 He is 99% certain its not the carb... He spent a lot of hours cleaning it, adjusting and tweaking to no avail Share this post Link to post Share on other sites
Irv 115 #5 Posted June 7, 2013 fuel filter? gas cap vent? Share this post Link to post Share on other sites
Manda 0 #6 Posted June 7, 2013 I checked the vent after reading about it on here.. that didn't solve it. He has a fuel filter on it that he only put on there last year so if its bad, its not visibly bad butcould be a cheap check to see if replacing it fixes it Share this post Link to post Share on other sites
tunahead72 2,553 #7 Posted June 7, 2013 New fuel lines? Any dirt in the gas tank? Air filter OK? Points and condenser OK, points gap set properly? I'll let someone more knowledgeable than me comment on whether the alternator/rectifier issue might be part of your problem. Good luck! Share this post Link to post Share on other sites
Ken B 3,189 #8 Posted June 7, 2013 Black smoke tells me its running rich, I'd say you need to make sure your float adjustment is correct or he needs to lean it up on the high speed adjustment. (which I like to do when the tractor is under a load) Make sure the choke is fully opening as well. Share this post Link to post Share on other sites
tunahead72 2,553 #9 Posted June 7, 2013 ... He actually took the rectifier off and its running off the battery and that worked fine for awhile and still ran smooth so he doesn't think that is the problem... Is this what you meant to say? If he removed the rectifier and the engine ran better, maybe the rectifier is part of the problem? I'm no electrical expert, maybe someone else can help out here. Another thought, when he cleaned the carb, did he remove the fuel needle(s) and clean them thoroughly? They may have tiny holes which should be run through with a tiny wire, or at least sprayed with a little carb cleaner. 1 Share this post Link to post Share on other sites
Manda 0 #10 Posted June 7, 2013 The rectifier is shot yes... but its still not on there but now its not running right anyways.. Today I am heading in for new fuel lines and a fuel filter... Share this post Link to post Share on other sites
Manda 0 #11 Posted June 7, 2013 fuel filter and new fuel line didn't change a thing. Fuel comes out when we tried testing the pump Share this post Link to post Share on other sites
Fordiesel69 271 #12 Posted June 8, 2013 Ok so the fuel is coming out good from the fuel pump. So you need to make a video of how it is running so we can all offer good suggestions. This will be faster and more conclusive than decribing in words. The charging system will not cuase a poor running engine unless the battery voltage drops below I beleive 11 volts. Once a certain low point is reached, the coil will not provide adequate spark. Without seeing / hearing a video, I am placing my bet on a carburetor malfunction or a problem with the points / condensor. Share this post Link to post Share on other sites
Save Old Iron 1,571 #13 Posted June 8, 2013 Make certain the battery voltage from the ignition switch is going to the (+) terminal of the ignition coil and the condenser and the points are hooked up to the (-) lead of the ignition coil. If the condenser is hooked up to the (+) coil lead or the condenser needs replacement, the engine may not run at all or very rough if it does finally fire up. The symptoms appear to be very much like a fuel issue. Share this post Link to post Share on other sites
WH nut 553 #14 Posted June 9, 2013 Make certain the battery voltage from the ignition switch is going to the (+) terminal of the ignition coil and the condenser and the points are hooked up to the (-) lead of the ignition coil. If the condenser is hooked up to the (+) coil lead or the condenser needs replacement, the engine may not run at all or very rough if it does finally fire up. The symptoms appear to be very much like a fuel issue. That is true, a bad condensor will make it act like its running rich because you may not get fire on every stroke which will load the cyling with fuel so when it does fire it will be rich. Cheap and easy check by replacing the condensor. Share this post Link to post Share on other sites
Manda 0 #15 Posted June 10, 2013 it was the Condenser and points! He replaced them and VIOLA! the problem is gone!! Share this post Link to post Share on other sites
rmaynard 16,354 #16 Posted June 10, 2013 Always glad when a problem is fixed with a simple solution. Share this post Link to post Share on other sites
Fordiesel69 271 #17 Posted June 12, 2013 Its amazing how many times points & condensor problems give you an impression of it being a fuel issue. As in when the condensor is failing, adding a bit of choke will help the engine to run smoother. Has stumped me many times in the past, now I have a known good spare coil, condensor, and points I can swap out at any time. Share this post Link to post Share on other sites
