My Z425 is 10 years old but only has 168 hours on it. It has the B&S 23HP Model 44L777 Type 0015 B1 engine.
After years of flawless operation, year before last it wouldn't start. I don't recall how, but I diagnosed it as a fuel issue. I replaced the hose, filter and fuel pump. Just for grins I also replaced the plugs and air filter. Still wouldn't start. Shop put another fuel pump on it. It ran fine for them and ran for me for about 15-20 minutes (one mowing of my back yard). After that, it wouldn't start. I was having some significant med issues so it sat idle for the next year.
Last fall I put a new carb on it. It ran ok for about two weeks then it wouldn't start again. This spring I put on another new carb. It worked great for two months. Now it won't start again.
I'm using new, clean gas from a national brand gas station. All my fuses are good. I have confirmed with an in-line tester that I have a strong spark. I am getting gas to the carb. I've tried tapping on the carb--no luck. I'm not a fan of starter fluid but I gave it a one-time shot. The engine ran for a few seconds but died as soon as the ether was used up. I think all of that tells me something is going on inside the carb.
I've spent several hours searching this and other forums for clues. I've seen some posts about the carb solenoid going bad but I have a hard time believing two of them went bad on brand new carbs, one after 30 minutes and the second in 2 or 3 hours. I'm clueless how to test it.
I can handle basic repairs but I'm not a mechanic and even less of an electrician. I'm hoping to avoid having to put it in the shop due to massive med bills for me and my wife doing a serious number on my finances. If any one has any ideas for me to try I would be very grateful, and even more so if you could be as explicit as possible.
Replace the solenoid with a bolt I think it is 5/16 UNF but you can measure the thread on the solenoid.
The important thing is not to make it too long.
Some small repair only workshops will carry them, big box shops will have trouble cause it is not on the computer.
Problem goes away then it is either the solenoid or the wiring to it.
And as you have swapped the carb a few times my money will be on the wiring.
Will depend upon the EPA regulations in OHIO.
When you turn the mower off, you stop the sparks but the engine continues to rotate for a few seconds.
While it is doing this fuel is being drawn into the engine and exhausted unburned into the air.
The solenoid stops this happening.
Now because the new mufflers run red hot ( to burn an scrap fuel that did not burn in the engine ) when the unburned fuel in your muffler gets to a combustable air : fuel ratio it will burn inside the muffler and go BANG.
So if running without the solenoid working you have to throttle down & wait a second or two before you shut down.
Let us know who you go.
For every person who plucks up the courage to post, there is another 5 who jut look at the solutions then go out & work on their mowers.
So solutions are always important
Will do. Between work and rain I haven't been able to work on it yet but will do so first chance I get.
One more question. Where do the wire leads from the fuel solenoid go? I've looked at wiring diagrams but they're like a foreign language and the actual wires disappear in an area that is not visually accessible. If I end up needing to replace them it would be nice to know what I'm doing before I start the process. Based on your earlier reply I'm still undecided on whether to do that as I always pull the throttle all the way down for 5-10 seconds before shutting down.
On new lean burn engines they should be started & stopped at full throttle.
If the solenoid has 2 wires, the ground wire goes to one of the screws that hold the meal cover around the cylinders on and the power wire goes up over the head then comes in at the main engine plug near the starter motor
I pulled the fuel shut off solenoid and replaced it with a short bolt. Voila! Engine started right up! Thanks BertsMobile1 for your expert advice!
Now I have a new problem that didn't exist before. When I release the parking brake the engine dies. I tried connecting the leads to the disconnected solenoid but that didn't solve it. Is there some other thing I need to do when the solenoid is removed...or is the parking brake issue just a coincidence?
Coincidence.
One of the safety switches or the wires to them is bad.
If you can not engage the blades then the seat switch or the seat switch relay will be the culprit
Thanks. After a bit of online research I had come to that conclusion...but it's good to hear from an expert that I'm on the right track.
I cannot release the brake or engage the PTO so I was guessing the seat switch. I did try jumping the seat switch connection but it didn't solve the problem so maybe it's the relay. I'll order both just to be on the safe side. Hope they get here before I need a baling machine!
I'm signing off now. Thanks again for your very helpful advice.
#12
dfbroxy
Bypassing the seat safety on a older JD cannot be done with a jumper wire. For testing purposes only, remove safety switch. Use a business card and cut to fit so that it will insert into the connector on the seat wiring harness connector. it must go exactly in the two places where the prongs connected. in between the two prongs will be a spring loaded piece of metal that grounds the two prongs out without a safety switch. The card must keep it from doing so.
Thanks for the tip. However, I had already purchased and installed a new seat switch. Unfortunately, that did not solve the problem. I also pulled the brake switch and tested the relay using a multi-tester. It tested good (continuity on one side without the button pushed; continuity on the other side only when the button is pushed). I'm now thinking it is a wiring problem.
Bad as I hate to, I think I'm going to have to put it in the shop. I just don't have the time (my lawn is turning into a hay field) or the expertise to sort this out.
