no start

[lilrobo]

i have a exmark zero turn , it cranks but no start ,i have checked compression and have 80 lb on each cyc, i have check most things ,, i was told my a guy it could be seat mod relay , i would though that would stop cranking ?
any help here ???
it is a fuel injection mower also a little over a year out of warranty my luck

thanks

 

[bertsmobile1]

Usually the safeties are organised like this.
Anything that will put a high load on the mower starer will stop the engine cranking.
So that is PTO, Gears & Brake. Not the seat switch, I have to be able to start the mower t service it.
To do that safely it can not move and the blades can not be turning so the Brake & PTO switches but be on & off respectively.

Once the engine is running the rest just kill the engine
PTO + seat switch
Brake + Seat switch
Brake + gears/ motion control

The odd one out is the carb solenoid, that is an EPA regulation.
Check tha by pouring a little gas down the carb, or some starter fluid.
Engine fires then the solenoid is duff.

Engine does not fire then find the magneto kill wire & disconnect it ,
Engine fires then you have a safety switch problem.
All of the ones that kill the engine are ground circuits so they are hard to diagnose.
Be very carefull as if you accidently send 12V down the kill wires to the coils, you kill the coild @ $ 80 each.

 

[lilrobo]

well i do have fire to plugs ,, dont make sense why it dont start ,, unless 70lb isnt enough compression ..

 

[bertsmobile1]

Sorry. I did read the bit about being fuel injeted then promptly sent you replies for a carb model :mur:
Crack one of the injectors and crank the motor a few times.
You should get fuel spirting out under considerable pressure.
That verifies the high pressure pump.
pull an injector out . hold it in a jumper of some sort to get an unbroken strong earth and crank again it should shoot fuel out.
If not you have a problem with either the computer or one of the safety shut off switches or the injector.

With your multimeter check each and every switch in , on & under the mower.
As far as I know every safety switch has to be connected or the module will shut down the mower

down side is that is about as far as a consummer can go.

 

[lilrobo]

i also have one that is surging,, when the mower is in low idle its seems fine when you switch it up to high or kick on the PTO ( high also ) it surges , what do you think that is ??