John Deere z425

Bigredcaseman

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I have a Z425 lawnmower it had a starting issue replace the carb on it and now it will only start with starting fluid but will stay running for the mower. Wouldn’t run at all with the old carb. Is something with this new carb I got the fuel ratio not right on starting? or am I missing something. Also it will start just fine when the engine is warmed up but you have to use starter fluid when the engine is cold to get it start with temps being 90° outside. Is it possible the car I got is not the right fuel ratio on starting. Any ideas or help would be great thank you
 

StarTech

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First make sure the choke is fully closing.

Second did you buy OEM carburetor or an after market one?
 

Bigredcaseman

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I bought an after market one and I think that’s where my problem is. And it does seem like my choke is fully closing.
 

slomo

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Couple tid bits to start on.

1.KEEP and remove OEM carb from engine. Break it down removing all small parts. Boil clean the carb on your stove top with water and those automatic dishwasher balls. Use a candy thermometer to keep water/soap temp at 200F. Boil for 30 minutes. Rinse well in clean water to neutralize after. Blow out with compressed air. Reassemble carb. Flip carb over and blow test carb needle/seat (fuel inlet pipe). Should hold 7psi for 30 minutes.
2.Remove fuel tank. Clean out 100% with compressed air. Install new fuel line, filter and shut off valve if you have room.
3.Clean block and cooling fins YEARLY per your engine manual. Remove top metal engine shroud exposing cooling fins. Neglect this and you will get engine damage.
4.Adjust valves per your engine manual yearly.
5.Decarbon cylinder and valves every 5 years or suggested interval in your engine manual. Neglect this and you will get engine damage.
6.Test ignition coil with old spark plug gaped to 0.250" or 1/4". Check for good blue spark. Check for spark if and when engine dies with inline spark tester.
 
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