I have a briggs and Stratton 23 ohv engine on a john deere zero turn 425 mower. It ran perfectly last week. went to start it this week to mow and now it sputters, black smoke and backfires all when trying to give it gas. it will not run fast nor can I engage the blades as the load makes it do the same thing and cut off. I changed the plugs, cleaned the carb, checked the valves, the blades move freely. It starts up and will idle and run on the lowest throttle setting but it will not do anything else. As soon as I try to push the throttle to fast and engage the blades it goes crazy. I don't know what else to try.
John Deere Z425 engine sputtering, shutting off under load or full throttle
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Boudreaux In Eunice La.
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Very common issue............. Run it for 10 minutes at idle then take the oil dip stick out and see if smoke comes out.......
If it does then you have 1 of your head gaskets blown........
There is a post on this same page that's 26 HP. same issue as yours I think......
Check compression on both sides the weaker side will be the one with the bad gasket......
I go thru a bunch of those..............
Let us know Mon Ami ~!~!
If it does then you have 1 of your head gaskets blown........
There is a post on this same page that's 26 HP. same issue as yours I think......
Check compression on both sides the weaker side will be the one with the bad gasket......
I go thru a bunch of those..............
Let us know Mon Ami ~!~!
Boudreaux In Eunice La.
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- Jul 22, 2017
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- 2,154
Do you have a V twin Engine ???? I jumped the gun on my first post..........
Could you please post the model and type of the engine please. Also have you done any reason maintenance without a couple of hours before this started and if so, what did you do.
The reason I ask is some of the Briggs Vanguards are picky with the spark plugs due to heat range, and Briggs has two air filters that look alike but are not, and both will cause the issues you are seeing within about 5 hours of changing those items.
The reason I ask is some of the Briggs Vanguards are picky with the spark plugs due to heat range, and Briggs has two air filters that look alike but are not, and both will cause the issues you are seeing within about 5 hours of changing those items.
it is a v twin the model number is 445577-0122-E1. I did find a crack in the intake manifold o-ring seal so I just bought 2 to replace them both and hope that does the trick. Not much smoke coming out at all just a little bit of black when it backfires no white smoke at all.
the maint was done after the we had the issues. had to clean the carb to start the season but that was it and has run perfect until now. I hope the intake manifold seals do the trick.
This is an old thread, but I had the same problem recently and tried multiple possible solutions mentioned on the web. None of them worked. By chance, I hit upon the solution while fiddling around with things...so posting my solution as a way to pay back all the times I found an answer someone else took the time to post.
My engine is a B&S. The intake manifold is made of plastic, and over time, it starts to warp as I indicated in the attached pic, causing it to leak where it is seated on the carb. This problem always got worse for me on inclines, maybe due to engine torque? Anyway, I got some liquid gasket and re-seated the old manifold to get me through the summer (worked fine as a temp solution), and replaced the manifold during the winter. Haven't had a problem since. Happy mowing!
