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OK guys a bit baffled. Have had this mower a couple years
Toro ZX4800 Titan. Would always start, sometimes had to move the brake handle a bit (safety).
Just serviced the deck, changed filters/fluids in the hydro's. Started it up, purrged the air etc. Now it won't start. You turn the key, and nothing.
I checked the ignition switch, its good. I checked the solenoid, seemed good, BUT, changed it anyway. Just checked for ground on the high side of solenoid (when key turned on) for the safety, get a positive ground.
the battery was good, (voltage) but swapped it out, and mower started. I was driving it around for 2 ,3 minutes, then it died. Same problem, no juice when turning the key. Disconnected the battery, and reconnected. Started again for a couple seconds. THEN figured it must be the electronic (5 pin starting circuit relay) which maybe was failing and grounding out,,or opening the circuit. So just installed a generic relay, and still nothing.
This is definately something electrical, and it has never been and issue before...... Any help, baffled. Once it cranks, it starts,
REALLY WOULD LIKE TO MOW THE LAWN, AFTER A COMPLETE SERVICE, OIL, BLADES AND FLUIDS

mauigts said:

OK guys a bit baffled. Have had this mower a couple years
Toro ZX4800 Titan. Would always start, sometimes had to move the brake handle a bit (safety).
Just serviced the deck, changed filters/fluids in the hydro's. Started it up, purrged the air etc. Now it won't start. You turn the key, and nothing.
I checked the ignition switch, its good. I checked the solenoid, seemed good, BUT, changed it anyway. Just checked for ground on the high side of solenoid (when key turned on) for the safety, get a positive ground.
the battery was good, (voltage) but swapped it out, and mower started. I was driving it around for 2 ,3 minutes, then it died. Same problem, no juice when turning the key. Disconnected the battery, and reconnected. Started again for a couple seconds. THEN figured it must be the electronic (5 pin starting circuit relay) which maybe was failing and grounding out,,or opening the circuit. So just installed a generic relay, and still nothing.
This is definately something electrical, and it has never been and issue before...... Any help, baffled. Once it cranks, it starts,
REALLY WOULD LIKE TO MOW THE LAWN, AFTER A COMPLETE SERVICE, OIL, BLADES AND FLUIDS

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First thing to do is this. STOP throwing parts at it. Use a test light and multimeter and start testing connections, etc. If you don’t have a test light or multimeter, or know how to use them, take mower to a shop.

Go through this troubleshooting procedure that I use and report back.
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. Check and make sure the chassis ground is clean and tight.
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.

Just shaking my head. The first hint was having to play with the parking brake. It is likely the switch is giving problems. In order for the starter solenoid to activate the ignition kill relay must operate grounding the starter solenoid. In order for this to happen the kill relay must operate. 12v is supplied to it primarily via the seat switch and both lap bars switches and brake switch along with the ignition switch depending on the brake and lap bars positions. The brake switch along with PTO switch override the seat switch when starting. Now with 12v going thru the seat switch they tend to burn the switch internal contacts of the seat switch. The lap bar switches, brake switch, PTO switch, and ignition switch are the common items controlling the kill relay when starting.

Hint is if the fuel solenoid on the carburetor is operating or not as it gets it power at the same time the kill relay gets its power. But you have listen carefully for the clicks.

Updafe: Found the problem. When I serviced everything . I REPACED THE FUSES, and cleaned the fuse block contacts. Evidently, I caused and "intermittent contact issue" when checking voltage present contacts, seems I would get voltage. But not always, and sometimes would crank, for a second. I had to correct the 30 amp fuse continuity with the fuse block. That fixed the intermittent problem. Starts immediately now, and am thinking g this might have been going on for awhile.... even with the previous owner, as there were times I had to turn the key a couple times before it would crank.

Thanks for all the input. Patience is nice to have as you get older