[AHTex]

Howdy all,
Id like to take a sledge to this mower, but then i wouldnt be able to mow my lawn. Anyhow Ive had little to no problems with this thing until the other day. I started it up and mowed for about an hour. After a quick break, i hopped on and it would crank but not fire. I was mowing some tall grass and it bogged down the engine to the point where it stalled out, but i was able to restart it until i took that break. Now nothing. I have fuel, spark and seems to have compression. New plugs last year, only clean fuel used. I am pulling my hair out at this point. Any thing else i should look for? I did notice that after cranking it, there was some pressure release at the oil fill cap. Not sure if thats normal or not. It seems like a simple fix, but who knows.. Any info would be greatly appreciated!

 

[be0354]

Don't know your tractor but have had BS twins for many years. Twice have had a valve stick open. Head warped. I would make sure there is compression on both cylinders.


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[Been There Twice]

First of all here, you shouldn't be mowing tall grass with these light weight mowers. They are not designed for such rough mowing. They may have a 23 hp to 27 hp powered engine, but they are not capable to handle the thick tall grasses.

Now, since you mentioned cranking the engine, you probably need to charge the battery to get the full 12 volts to the starter. If that don't work, you may have damage, broken a value push rod when the engine over-ran the value train. Back pressure out of the oil fill tube indicates that symptoms.

Remove one spark plug and take a lead pencil or a small round wooden dowel and stick it in the s.plug hole and turn the PTO/Crankshaft pulley to get some compression(pressure) on that cylinder. If no pressure, values (intake and exhaust) are stuck open. If you have pressure on that cylinder, do the other side. You are trying to find if there is a value guide(pushrod problem)

 

[AHTex]

You mean I cant mow 4ft Texas grass with this guy? Haha, thats what happens when i let it go too long. Anyhow you were correct. I opened up the valve cover and found the exhaust push rod had slipped off at the rocker arm. It didnt appear to be bent. I pulled off the other cover and it had done the same thing. I reset rods and the clearances and all seems to be good. It fired up, smoked a bit, and then ran great. Anything else I should do?

 

[Been There Twice]

You mean I cant mow 4ft Texas grass with this guy? Haha, thats what happens when i let it go too long. Anyhow you were correct. I opened up the valve cover and found the exhaust push rod had slipped off at the rocker arm. It didnt appear to be bent. I pulled off the other cover and it had done the same thing. I reset rods and the clearances and all seems to be good. It fired up, smoked a bit, and then ran great. Anything else I should do?

Not too many mowers will cut 4 foot tall grass. Get you a 6 ft. finishing mowers an to cut the tall stuff. Once it's down to about 5 inches, than you can use the Z425.

The problems with any V-twin is the way they have the overhead-value setup versus the push-rods assembly. The manufacturers never really set out to remedy this problem with the push-rods releasing from the lifter cup