Kubota Zero Turn won't start.

[Wiz222]

Kubota z122EBR (residential gas) mower. 154 hours. Purchased used with a little over 100 hours a couple of years ago. It has a 22 HP Briggs & Stratton Professional Series engine.

Won't start:

• Cranks fine, just doesn't seem to fire
• Spark testers show spark on both cylinders (one may be weaker than the other. Hard to tell in daylight)
• Spark Plugs changed last season.
• Lift your butt off the seat, won't crank
• If the parking brake is not engaged, it won't crank
• Engage/disengage the mower deck I hear a click, and won't crank while engaged.
• Move either steering bar in, won't crank.
• I see gas in the fuel filter.
• The tank was about 1/4 full when it died. Added more gas.
• The engine has oil. The last time it was used, which was the first time this season, it was running poorly and I parked it. Later when I checked on it, it had an oil puddle under it and discovered the oil filter had come loose over the winter and it was low on oil. I changed the oil and filter. It ran fine for 45 minutes or more before dying.

Looking for where do I start to diagnose? TIA!

 

[ILENGINE]

Try adding a small amount of gas into the intake and see if it starts and continues to run, starts and then dies, or doesn't start at all.

 

[sivicman]

A friend of mine had this problem where it would crank, but not start. Come to find out the valves were out of adjustment.

 

[Rivets]

Slomo, WHY???

 

[mcspeed]

Kubota z122EBR (residential gas) mower. 154 hours. Purchased used with a little over 100 hours a couple of years ago. It has a 22 HP Briggs & Stratton Professional Series engine.

Won't start:

• Cranks fine, just doesn't seem to fire
• Spark testers show spark on both cylinders (one may be weaker than the other. Hard to tell in daylight)
• Spark Plugs changed last season.
• Lift your butt off the seat, won't crank
• If the parking brake is not engaged, it won't crank
• Engage/disengage the mower deck I hear a click, and won't crank while engaged.
• Move either steering bar in, won't crank.
• I see gas in the fuel filter.
• The tank was about 1/4 full when it died. Added more gas.
• The engine has oil. The last time it was used, which was the first time this season, it was running poorly and I parked it. Later when I checked on it, it had an oil puddle under it and discovered the oil filter had come loose over the winter and it was low on oil. I changed the oil and filter. It ran fine for 45 minutes or more before dying.

Looking for where do I start to diagnose? TIA!

Most likely carburetor issue. Sitting with fuel in it tends to cause issues. Remove carb, clean it thoroughly, or I’d just rebuild it using OEM kit. DO NOT buy Chicom rebuild kit or carb……you will regret it.

 

[lugbolt]

I ain't never had much luck cleaning those briggs and scrapiron carburetors (nikki I think they are?). Junk. Seriously. I have replaced a few of them, though.

 

[Wiz222]

Update: I finally got back to working on this. I replaced the carb which didn't change anything. I decided to run a compression test and got 0 lbs on the right cylinder and 50 lbs on the left. I think my camshaft is broke/bent/not working.

 

[bertsmobile1]

Way back there was a suggestion to pull the rocker covers and check the vale lash
Now is a good time to do just that
Pushrods jump off all the time
An inlet with no pushrod = 0 PSI
50 psi is a bit on the low side but it still should fire
Low oil often leads to gauled / stuck valves but rarely a stuffed cam
You will usually seize in the bore before you wreck a cam .