I have a john deere 185 hydro around 10 yrs old.the battry was hooked up backwards at one point ,I have checked fuses.mower won't start with key switch,only by crossing the starter solenoid.it runs for 5 seconds then quits.I have checked all lines to carb and all are getting gas.can you help?

Hi,
You have a 17 HP Kawasaki engine on that machine and it has a solenoid on the carb to shut off the fuel supply. If you cannot hear or feel it open, then you have no fuel supply.
The battery in backwards will not generally harm that model. You have something else going on. That model generally has problems with ignition swich, harness under dash and PTO switch. The battery is right there with all those components and can cause nasty corrosion problems.
To give you what I can on the info supplied; the battery voltage enters the wiring harness at the starter solenoid(on the starter) and goes through the PTO switch and ignition switch to reach the starter solenoid trigger. The first wire (in) should be red (solenoid and ignition switch) and blue (PTO switch.) It may or may not go to a brake switch (behind the right hand side panel at the base of the pedestal - dash mounted to top of pedestal.) At any rate the trigger wire should be a light purple in color; if it gets no voltage in the start position, that is the symptom you actually describe. The wire to the anti-backfire solenoid will be yellow or blue. Several carbs and two transmissions were used on that model
Peace,
crigby