What did we fry?
- Thread starter gerry100
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slowrev
Elite Member
You will have to remove the engine cover from over the flywheel.
The flywheel key locks the flywheel in place on the crankshaft. The flywheel will have to be removed, but usually not just to check. Just remove the nut and washer that holds it on, then look closely you should see a square groove in the flywheel where it slips on over the crankshaft, if you are lucky you can see the matching groove in the crankshaft. They should be perfectly aligned, if not remove the flywhell with an appropriate puller and replace the key that fits in the 2 slots and keeps the flywheel in time with the crankshaft.
The flywheel key locks the flywheel in place on the crankshaft. The flywheel will have to be removed, but usually not just to check. Just remove the nut and washer that holds it on, then look closely you should see a square groove in the flywheel where it slips on over the crankshaft, if you are lucky you can see the matching groove in the crankshaft. They should be perfectly aligned, if not remove the flywhell with an appropriate puller and replace the key that fits in the 2 slots and keeps the flywheel in time with the crankshaft.
jinman
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Since you didn't even turn the engine over with the battery reversed, I don't think you did anything with the flywheel key. That happens more on push mowers than riding mowers anyhow. The flywheel key is a shear key that breaks to protect the crankshaft when you hit an immovable object with the blade.
I think your problem is the ignition "kill" wire. The ignition or some other safety switch will ground that wire just the same as if you turned the key off. You can normally just unplug the wire and the engine will start. If it does start, then you have to troubleshoot the safety switches to find out which one is causing the problem. Two that are most suspect are the reverse kill switch and the operator present switch under the seat. The reverse kill switch will kill the engine if you have the blades engaged and put the mower in reverse. I normally defeat that switch on all my riding mowers. The operator present switch will not allow the mower to start if you are not sitting on the seat.
I think your problem is the ignition "kill" wire. The ignition or some other safety switch will ground that wire just the same as if you turned the key off. You can normally just unplug the wire and the engine will start. If it does start, then you have to troubleshoot the safety switches to find out which one is causing the problem. Two that are most suspect are the reverse kill switch and the operator present switch under the seat. The reverse kill switch will kill the engine if you have the blades engaged and put the mower in reverse. I normally defeat that switch on all my riding mowers. The operator present switch will not allow the mower to start if you are not sitting on the seat.
While tinkering I noticed that the plug that I cleaned was still dry after a long try at starting and that the fuel filter was also dry.
The fuel pump is on the side of the engine and I assume is mechanical. Since the engine never ran in reverse, I don't think that is damaged.
But there is something called a fuel solenoid there somewhere.
Could this solenoid be messed up or stuck due to the reverse charge and subsequent start attempt?
Inputs appreciated as always.
The fuel pump is on the side of the engine and I assume is mechanical. Since the engine never ran in reverse, I don't think that is damaged.
But there is something called a fuel solenoid there somewhere.
Could this solenoid be messed up or stuck due to the reverse charge and subsequent start attempt?
Inputs appreciated as always.
Is there an actual spark at the plug gap when its pulled out of the engine and checked while cranking?
I don't know what make/model engine you have, but many small engines, even ones 10-12 years old have electronic capacitor discharge ignition modules that can be destroyed by polarity reversal. In that case there will be no spark at all, and the module has to be replaced. The voltage regulator/rectifier and/or alternator stator can also be damaged, which you might discover after getting the engine running that it will not charge the battery at all. The fuel shutoff solenoid is also a DC component, but I tried polarity reversal on an old one I had in the shop and it was not damaged. Not trying to scare you, just throwing out some ideas.
The easiest way to distinguish between fuel or ignition no-start problems is to spray a little gumout or starting fluid down the air intake and try to start it. If the ignition is OK, the engine will usually start and run for a few seconds and stop, this indicating a fuel delivery problem. If it does not start at all, it's often ignition system at fault.
-Fordlords-
I don't know what make/model engine you have, but many small engines, even ones 10-12 years old have electronic capacitor discharge ignition modules that can be destroyed by polarity reversal. In that case there will be no spark at all, and the module has to be replaced. The voltage regulator/rectifier and/or alternator stator can also be damaged, which you might discover after getting the engine running that it will not charge the battery at all. The fuel shutoff solenoid is also a DC component, but I tried polarity reversal on an old one I had in the shop and it was not damaged. Not trying to scare you, just throwing out some ideas.
The easiest way to distinguish between fuel or ignition no-start problems is to spray a little gumout or starting fluid down the air intake and try to start it. If the ignition is OK, the engine will usually start and run for a few seconds and stop, this indicating a fuel delivery problem. If it does not start at all, it's often ignition system at fault.
-Fordlords-
Good stuff.
I'll look at the wiring chart, but the only solid state looking module is a box with wires going into it filled with potting compound - I asume all the components would be in there.
I'll also try the gumout test and let you know.
I'll look at the wiring chart, but the only solid state looking module is a box with wires going into it filled with potting compound - I asume all the components would be in there.
I'll also try the gumout test and let you know.
Engine will run for a few seconds on starter fluid. I pulled the fuel solenoid and it's working.
Problem seems to be no fuel getting form the tank thru the fuel pump to the carb bowl.
Guess I'll check the fuel lines an dth epump.
Is it possible/necessary to prime the fuel pump?.
Problem seems to be no fuel getting form the tank thru the fuel pump to the carb bowl.
Guess I'll check the fuel lines an dth epump.
Is it possible/necessary to prime the fuel pump?.
After checking the fuel lines and the filter, I primed it by pouring gas into the line before the pump.
Started right up and ran until the tank ran dry, A few minutes.
I think the fuel tank was too low to prime the fuel sysyte,m and draw gas.
I know there wa sgas in thew tank when I checked testerday.
Murphy likes you to spend hours on something beofre you stumble on something that is ,in retrospect, obvious.
Tanks for trying to help.
Started right up and ran until the tank ran dry, A few minutes.
I think the fuel tank was too low to prime the fuel sysyte,m and draw gas.
I know there wa sgas in thew tank when I checked testerday.
Murphy likes you to spend hours on something beofre you stumble on something that is ,in retrospect, obvious.
Tanks for trying to help.
No problem 
I ran into this same stumper a few months back when my 682 was running rough and backfiring, yet it looked like there was still gas in the tank. Finally after fussing with everything I could fuss with I topped the tank up with gas and it was fine. I almost always panic before I stop to think about the easy stuff, someone told me that is a trait of the mechanical type of mind
-Fordlords-
I ran into this same stumper a few months back when my 682 was running rough and backfiring, yet it looked like there was still gas in the tank. Finally after fussing with everything I could fuss with I topped the tank up with gas and it was fine. I almost always panic before I stop to think about the easy stuff, someone told me that is a trait of the mechanical type of mind -Fordlords-
