Mower will not start

[bigge31566]

I have a Bunton 72" mower with 31 hp Briggs, and mower will not crank when hot, I think it is in the starter, it just clicks, someone said it was the starter relay, I have already replaced starter and solenoid, I did not know it had a relay too, do anyone know where to look for it at, or if it really do have one?

 

[Mac in PA]

I'll give you my 2 cents worth.

You said it just clicks when trying to start it. This is a good indication that the battery has low voltage.

The first thing to do when troubleshooting a starting problem is to verify that the battery connections are clean and tight. Then check the voltage at the battery while trying to start the engine. If it drops below 10 volts then the battery is bad or not getting charged by the charging system. If voltage is good at the battery then you need to check the voltage at the starter while trying to start the engine.

All voltage checks need to be done when the engine won't crank.


Mac

 

[DaveTN]

I have a Bunton 72" mower with 31 hp Briggs, and mower will not crank when hot, I think it is in the starter, it just clicks, someone said it was the starter relay, I have already replaced starter and solenoid, I did not know it had a relay too, do anyone know where to look for it at, or if it really do have one?

I assume it cranks over and starts easy when cold? Does it bog down when it gets progressively hotter? Or do you shut it off after mowing, then it won't crank over? How long has it been like this? My cousin had a 14 HP single cylinder B&S that would start and run cold, but let it mow a few minutes and it would lug and bog down and finally seize up. What it wound up being was the top crankshaft bushing starving for oil. In his case I had to take the engine apart and remove the rod cap and crankshaft just to replace the bushing! Hope this is not your case.

 

[Rivets]

I agree with Mac, the battery is the most common cause given your symptoms. Here is a sequence that may help in your search. There is no other relay in your system as far as I know.



Electrical* problems can be very easy or very difficult, depending on four things.
1. * How well you understand basic electricity.
2. *What tools you have and know how to use.
3. *How well you follow directions.
4. *You don't overlook or assume anything and verify everything.

Remember we cannot see what you are doing. *You are our eyes, ears and fingers in solving this problem. *You must be as accurate as you can when you report back. *The two basic tools we will ask you to use are a test light and a multi-meter. *If you have an assistant when going through these tests it would be very helpful. *These steps work the best when done in order, so please don't jump around. *Now let's solve this problem.

First, check the fuse(s), check battery connections for corrosion (clean if necessary) and *voltage - above 12.5 volts should be good.*

Second, check for power from the battery to one of the large terminals on the solenoid. *One of the wires is connected directly to the battery and has power all the time so one of the large terminals should light a test light or show 12 volts on a meter at all times.*

Third, *check for power at the small terminal of the solenoid while depressing the clutch/brake pedal and holding the key in the start position (you may need an assistant to sit in the seat to override the safety switch). If your solenoid is a four wire solenoid, check both small wire terminals as one is ground and the other is power from the ignition switch. *If your solenoid is a three wire solenoid, make sure the solenoid body is not corroded where it bolts to the chassis of the mower as this is your ground path back to the battery. *If in doubt, remove the solenoid and clean the mounting area down to bare metal. *If there is no power to the small terminal then your problem is most likely a safety switch, ignition switch or in the wiring.*

Fourth, check for power on the other large terminal of the solenoid while holding the key in the start position (you may need an assistant to sit in the seat to override the safety switch).*

Fifth, check for power at the starter while holding the key in the start position (assistant again).*

Sixth, check your ground circuit back to the battery.

After you have gone through each of the above steps, let us know what happened when you did each step. *At that point we will have great info to tell you how to proceed. *Remember you are our eyes, ears, and fingers, so please be as accurate as possible.

Be as specific as possible with voltage readings as this will help diagnose your problem quicker. *If you do not know how to perform the above checks, just ask and I will try to guide you through it. *Youtube also has some videos and as you know a picture is worth a thousand words.