JD- ZtrackZ425

[macdoesit]

Bought new in 2010. one cylinder is dead. I took the ignition coil and sparkplug and switched them around, the good cylinder fired but the dead cylinder is still dead.
Can anyone tell me what the problem is??
Thank you

 

[ILENGINE]

Remove the spark plug and turn the engine over slowly by hand and see if that piston is going up and down. Remove the valve covers and see if the push rods are still in place and not fallen out.

 

[macdoesit]

Remove the spark plug and turn the engine over slowly by hand and see if that piston is going up and down. Remove the valve covers and see if the push rods are still in place and not fallen out.

If that was the case, wouldn't it make a loud knocking noise while running. It does run but only on one cylinder.
I did take the spark plug out and started it and air came out of the cylinder.

 

[ILENGINE]

It may not knock even if one rod is broke. And a missing push rod will prevent it from running on that cylinder. Intake push rod won't normally cause a popping noise. Sometimes the exhaust valve push rod missing can cause a popping back through the intake, but not always.

 

[macdoesit]

It may not knock even if one rod is broke. And a missing push rod will prevent it from running on that cylinder. Intake push rod won't normally cause a popping noise. Sometimes the exhaust valve push rod missing can cause a popping back through the intake, but not always.

Compression is at 88 and no bleed off

 

[StarTech]

These Briggs engines uses a two piece intake manifold that is fused together. They do split sometimes causing problems.

 

[Tiger Small Engine]

Compression is at 88 and no bleed off

Remove valve cover, as previously stated, and look at intake and exhaust valves. Are push rods in place and not bent? Are the springs moving freely and equally? 88 psi compression is on the low end. Is that reading from the cylinder that is not firing?

 

[Auto Doc's]

Disconnect the coil kill wire on each coil and see if the engine now runs on both cylinders. The engine can be shut down by the after-fire solenoid on the carburetor, when the key is turned off.

If it does run fine disconnected, the kill wire harness has a bad inline diode for one of the coils.

Use the numbers stamped into the top of one of the valve covers to look for parts. Parts Tree, Ereplacement.com or Jack's small engine should show the kill wire harness but be careful of which one you have, because they had a couple of different ones.

 

[macdoesit]

Took valve cover off. one exhaust and intake pushrods, one was laying under rocker arm broke, the other I assume is in the bottom of the engine. I ordered both rods, both valve tappets. Is there anything else I need to order?
Can rods be replaced without breaking down the engine?

 

[macdoesit]

Bought a new 54inch cut JD yesterday. These new ones ride like Cadillacs, and cost about the same. LOL