John Deere LT166 starting

[70 plus]

Hi folks

I have had a John Deere LT166 for about 20 years with no major issues but recently when I turned the key to the start position nothing happened even though it started a few minutes earlier.
So I checked the battery and have a full charge, I removed and cleaned the contacts on the starter switch. Still no action.
Then I turned the starter switch to the off position and shorted the solenoid which turned over the starter motor.
Then I turned the starter switch to the start position then shorted the solenoid and the engine started and ran.

Has anyone run into this issue and if yes what did you do to resolve the problem?

 

[3Lfarms]

When you turn the key to the crank position, does the starter solenoid click at all? If not, then you have an issue between the ignition switch and starter. Put a multimeter on the small wire on the starter coming from the ignition switch and see if you are getting 12 volts when the key is turned to the crank position.
If you get power, but it’s less than 12 volts, I’d start checking all connections in the wire back to the switch looking for a loose or corroded connection.

If the starter clicks when the key is turned, but the motor doesn’t spin, then you still need to ensure you have close to 12 volts. 9 volts is usually enough to make it click, but not enough to get the main contacts in the starter solenoid to close and send power to the starter motor.

 

[70 plus]

When you turn the key to the crank position, does the starter solenoid click at all? If not, then you have an issue between the ignition switch and starter. Put a multimeter on the small wire on the starter coming from the ignition switch and see if you are getting 12 volts when the key is turned to the crank position.
If you get power, but it痴 less than 12 volts, I壇 start checking all connections in the wire back to the switch looking for a loose or corroded connection.

If the starter clicks when the key is turned, but the motor doesn稚 spin, then you still need to ensure you have close to 12 volts. 9 volts is usually enough to make it click, but not enough to get the main contacts in the starter solenoid to close and send power to the starter motor.

There were no sounds at all so I started pulling all the safety switches and found the blade engaged switch was busted because when I shorted it out the mower started. Now just have to wait for some warm weather to change it.

Thanks or the input.

 

[70 plus]

Getting back to this now.

Still no joy with the starting via the key.

When I short out the solenoid it will start and run but as soon as I stop shorting out the solenoid the motor stops.

Any suggestions?

 

[tomplum]

Has this machine been run in the last 5 years?

 

[70 plus]

Yes, I used it all last year.

It has not started with the key since the end of last year.

I did put in a new solenoid this year but that is not the problem since it turns over and starts when I short out the solenoid but will only run for a few seconds then stops. I also put new fuel in.

 

[tom3]

Did you ever replace that blade safety switch? When shorting out the starter solenoid you're back feeding the system - but the engine runs on the magneto ignition so it should stay running. Somewhere a relay is dropping out and shorting the ignition. This seems like a really strange problem?

 

[70 plus]

Thanks I will pull the bed and check that out.

 

[70 plus]

While that problem was solved it seems it lasted two years now I have another issue.
When I try to start it, the engine continues to back fire out of the carb while turning over but does not start. I have replaced the fuel put a new fuel filter on and added new gas, removed a cleaned the air filter, removed and cleaned the carb, checked the solenoid which is giving me spark and the plunger depresses, removed the flywheel and verified that the shear pin is intact, replaced both spark plugs and confirmed I'm getting spark, also checked the compression on the two cylinders 120 on one and 150 on the other, starter is strong and fuel pump is functioning, checked the brake safety switch and the blade engage safety switch both work.
I am running out of options any suggestions as to what I should check next?

 

[tomplum]

It sounds like it is time to remove the valve covers and give close look. Look that the rocker hardware is tight, that all four valves close, compare how much they open etc. Be sure that the flywheel is good and tight or you can shear the key.