ignition module

[powerstroke6ltr]

Hello again. I finally got the old tractor to work and worked with it for about 3 hrs. or so. Then after driving it around for a while, it jsut died on me. I though....hmmm that's odd. Tried jumping it and it cranks but doesn't turn over. Very weird. I took out the spark plug with the boot still attached and cranked the motor with the threads touching painted metal. Every so often the brand new plug would arc, but very rarely. Even with starting fluid and a warm plug from another machine, the tractor won't turn over. Then plug just gets really wet. The tractor ran perfect before it just died. Any ideas? Could it be the magneto? The tractor is an 11hp briggs from 1981-ish. I painted over the flywheel magnet, could that be why? Only problem is, the tractor ran perfect with the paint on the magneto. Help! Thanks! /forums/images/graemlins/confused.gif

 

[powerstroke6ltr]

Any help?? /forums/images/graemlins/confused.gif /forums/images/graemlins/confused.gif

 

[GaryE]

I don't know if an 81 ish Briggs still had points and condenser. That would be the first thing I would check. It sounds like it is only giving you spark intermittently. A badly pitted set of points could cause that.

Next check the primary and secondary side of the coil / mag for continuity. This is at least a place to start.


Gary

 

[aardvark]

Paint on the magnet won't affect the magneto. I'd try swapping out the magneto if you think that's the problem. Another area to look is the carburetor. Maybe the float is stuck and it's flooding the engine.

 

[powerstroke6ltr]

thanks for the help! I am going to check the float...don't know how it would get frozen up, but that sounds right, because if i look in the carb while cranking, it gets so wet, the fuel will build a small puddle. Then it will go through the screw hole ont eh ground. How do I check the continuity? I can get access to both legs...thanks again

 

[aardvark]

Another thing to try to eliminate the possibility of the magneto being bad. Remove the carburetor completely, make sure the ignition is fully installed, spray some starter fluid into the open intake manifold, and try cranking the engine over. It should start and run for a second on just the starter fluid.

 

[powerstroke6ltr]

Won't that make the motor overspeed? Abundant supply of oxygen and a fuel? Tried that once /forums/images/graemlins/grin.gif...bad idea. Fun while it lasted though. I could always turn it off by turning the key though...I'll try that. thanks again. Also, how small are the pathways on a 5hp generator engine carb? have another engine needing assistance.lol The engine runs with fuel dumped directly in the intake way, but won't run off new fuel in the tank. The pedestal isn't clogged either...I don't believe. How can I clear the carb pathways on this engine? So many engines, so little time...May have to take off work tomorrow... /forums/images/graemlins/frown.gif /forums/images/graemlins/grin.gif

 

[aardvark]

Overspeed? No. It's going to run for about two seconds and then shut off. There won't be enough starter fluid for it to run for any significant amount of time. Just spray a single shot into the intake, don't spray the starter fluid continuously.

The ports are pretty small. Buy a gallon continer of Gunk brand carb cleaner, dissassemble the carb, and let the main housing soak in the carb cleaner for a few days.

 

[powerstroke6ltr]

that'll probably get rid of the dirt or gunk or whatever is in it? So do those sound like symptoms to a clogged carb?? Thanks again

 

[Catmando]

I would try everything else before I tried starter fluid. It doesn't take much starter fluid to make the engine sound like it is coming apart.

Took an hard to start engine apart that had been started using starter fluid. It needed a new piston to replace the one that was broken.

If it has points that is the most likely suspect. I have a 1976 16 hp Briggs. When it doesn't fire I know that it is time to take the point cover off and burnish the points.

 

[hhw]

It seems that you need to take a long look at your spark generation. If your plug is intermittently sparking that is a sign of spark generation/timing problems. As stated earlier: If it has points, probably the problem. If it doesn't have points and your spark is weak, intermittent or just plain absent problem should exist between plug and mag, i.e. bad plug, bad plug wire or mag problems. I have had mags go in such a way that they would work until the motor developed heat then they would fail. This made me scratch my head because I was always told, "when mags go they go comlpetely." Good luck

 

[PineRidge]

<font color="blue"> I took out the spark plug with the boot still attached and cranked the motor with the threads touching painted metal. </font>

The spark plug threads should be against unpainted metal when cranking the engine to test for spark. If it's still intermittent messing with the carb isn't going to help your problem. You will first need to address why the spark is weak. Points, plugs, condenser, wires, and so on.

 

[boustany]

occasional spark could be caused by a bunch of things: the usual suspects, namely points, rotor, capacitor, coil, wires, caps, and plug. New plug so it ain't likely that.

I once diagnosed my father's 1968 Monaco (a big deal for me because I was only 14 or so) because it was getting dark and I spotted arcing. I can't remember if it was because of crud or cracks or a combination of both, but if you have a hard to diagnose ignition problem, consider checking it out at dusk.

 

[HankC]

Lots of good advice here. Does sound as an ignition problem.
Just one other area you may look at that is easily overlooked.
Make sure your key on the magneto is good (as well as the key ways) just the slightest indent on the key may be sufficient to throw off your ignition.

 

[Darellk]

Well here's another overlooked thing about point type ignition. The condenser must have a good ground. If the little screw becomes loose or gets a little rusty under the condenser you will loose the path to ground and loose spark. Acts just like a bad coil. Make sure you have voltage to the points from the ignition switch. Might have a loose wire at the switch. Just a few more things to consider. Hope you get'er going.

 

[powerstroke6ltr]

thanks for all of the help. Has sent me out to the garage many times! I tried starting on fluid...huh. No start. With the carb off. Sounds to me like the ignition magneto needs replacing. I don't think it is points and condensor, because It is almost identical to the magneto on my 10 year old generator... Still confused...may just buy a new magneto...

 

[powerstroke6ltr]

IT WORKS!! /forums/images/graemlins/smile.gif Turned out to be the flywheel key somehow got sheared in half. VERY weird, because the engine didn't have ayn sudden load changes. odd. Problem now is, the key doesn't work at all. I replaced the switch, and nothing happens. I turn the key and the solenoid doesn't even cycle. Tried starting the motor by touching the two large posts together...no go. There are no safety switches either. I jumped the tractor by just going straight to the starter and...the engine started. Starter is good, key switch is good (unless I had two bad ones ina row). Now it seems my solenoid has ONCE AGAIN gone bad. What a waste of $16. any ideas? Oh, the wires are about 12 gauge all the way around. I do remember them getting warm when I cranked the motor over. The negative cable insulation has found a way to burn somehow. What gauge should I be using then? thanks