B&S 22 HP V Twin in JD Z425 - Bad Miss / Stumble under load

tr0y

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  • / B&S 22 HP V Twin in JD Z425 - Bad Miss / Stumble under load
Hi All !

New here as I just moved to the upper midwest from the desert and I now have lawn that needs to be cut ...

I have a couple year old John Deere Z425 with the Briggs and Stratton 22HP Vtwin motor, it was running great when we pulled it out of winter storage and cut the grass for the first time this year then it decided to start acting up. It was stored with ethanol free fuel with stabilizer over the winter.

Te strange part here is this was / is all of a sudden, it was running fine and then awful with no power

Here are the symptoms / issues / how it runs

1. Cold mower starts right up and idles on choke and idles off choke. Runs fine no misses.
2. Warm mower starts and idles without choke and will idle at full throttle.
3. You can engage the controls and the mower will drive forward and backward make turns.

Now it gets ugly

4. While moving forward when you engage the blades / mowing deck the mover almost dies.
5. Post engagement of the cutting blades the motor does not recover, idles poorly, zero power, black smoke.
6. If you return the throttle to the full slow position the mower does not recover.
7. Sometimes if you stop and restart the mower it will idle again without missing.
8. Sometimes it won't..
9. If you let the mower fully cool down it will restart and idle.

What I have done to attempt to resolve this.

1. New Fuel
2. New Fuel Filter
3. Confirmed that the fuel pump is functional
4. Cleaned Air filter
5. Removed Carb, disassembled and cleaned in ultrasonic cleaner / bath at 115 degrees for 3 hours
5. Ran jet cleaning tool through all jest and passages I could get to
6. Blew carb out with compressed air
7. Repeated line 5 ( 5. Removed Carb, disassembled and cleaned in ultrasonic cleaner / bath at 115 degrees for 3 hours)
8. Replaced Spark Plugs

Ok all if anyone can help me it is greatly appreciated.

Thanks and I look forward to being a part of your community.
 

BlazNT

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  • / B&S 22 HP V Twin in JD Z425 - Bad Miss / Stumble under load
My thought would be coil going bad when hot. You need an inline spark tester to see if you are losing spark when this happens.

Don't forget we really need the model number off the Engine.
 

tr0y

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  • / B&S 22 HP V Twin in JD Z425 - Bad Miss / Stumble under load
Thanks, it is dark here now and the machine is out in a shed. I will get the motor model in the AM .

Thanks !
 
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