glow plugs for 721D ???

I DID turn the key to the left to the pre-heat cycle, counted to 10, then turn the other way to start. Motor just cranked & cranked but would not start. Good fuel, full charge on new battery, but nothing. A few days later when the temp was above freezing I followed the exact same steps and it started just fine. That's why I wondered if there was a chance the glow plugs were bad. It hard to tell about such things during the summer season when the temp is 70 and above. I asked about plugging the engine in since my '84 F-250HD diesel pickup had a block heater with a 120v pigtail hanging out the front grill to plug in - there is no such thing on this mower.

Not crazy about trying to force it to start with fluid or other bypass/cheater "tricks" - the mower should start & function properly without coercing it.

reynoldston,
I prefaced my original post by stating it might sound like a dumb question. Even so, I really don't appreciate being basically told I don't know my 'A' from a hole in the ground.

reynoldston,
I prefaced my original post by stating it might sound like a dumb question. Even so, I really don't appreciate being basically told I don't know my 'A' from a hole in the ground.[/QUOTE]

Lets be very clear here. We don't know each other and I am sorry if I offended you because I didn't mean to. I don't know your skills and you don't know mine. All I was tiring to say if you don't know the system it can be cheaper to have help with the repairs. I was working on diesels in the 70s and 80s as I recall there was a lot to the glow plug system. I guess everyone on this forum on top of what they did for a living they are also a master mechanic with a complete shop full of tools and knows every wire and color of every electrical system on every tractor ever made. ( I don't) I also know as a fact if your tractor was sitting in my shop I could repair it. You might want to start with a wiring diagram because that will be your road map for the repairs and that would also be my start for the repairs even if I had to buy one. Best of luck even if you do hate me.

reynoldston said:

You are thinking back in years pass. Yes that was a problem in the earlier years but since then they have added a additive in the starter fluid to prevent that problem. Another thing all it takes is a small pass by the air cleaner to work. In all the years of working in the repair trade I have never came across damage caused by starter fluid. I really don't know if the PO has glow plugs on his diesel or not, but if he dose I do agree he should get them working. I also recall when I was working on diesels the glow plugs and the relay that operated them were big money to replace.

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173abn said:

I stand corrected on the starter fluid issue but I did say use the one w/the lubricant.I think he should turn his key to the left,opposite the way to start to see if that activates the glow plugs...russ

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You don't need a gallon of eather. Just a spritz. About a second is usually more than enough

Well first off, going back to the original post, the 120V cord you were plugging in on your truck was for the block heater, and had NOTHING to do with the glow plugs. Glow plugs are a 12 volt system. It is most likely possible to put a block heater on your GH engine, but I don't believe many (if any) came with them from the factory. The first thing to establish is whether you are getting voltage to the glow plugs themselves, an easy job with a test light. I just had an issue with my Kubota tractor where the power wire to the glow plug bus bar busted off, rendering the plugs inoperative. If you have good voltage at the glow plugs, it is indeed possible they are bad, but you would want to do further testing before going crazy buying new ones. If you do NOT have voltage at the glow plug, then you need to backtrack and find out where power stops. Fuses and broken wires are the starting point. After that, the ignition switch and the glow plug timer. You will likely need a wiring schematic to do that. Also a folow up on some earlier posts. NEVER use starting fluid on an engine that has working or possibly working glow plugs or an inlet air heating element. At the very least you could damage the glow plugs or the heating element. At worst you can cause an explosion which in some cases can blow the intake manifold right off the engine. Most all of us have used starting fluid at some point, but it is really just a crutch for some other problem you have. Much better to fix the problem than crutch around it. For one thing, diesels are designed for a fuel source that is quite difficult to ignite, and introducing a fuel that ignites VERY quickly can in the long term do damage similar to spark knock in a gasoline engine. It also has a nasty habit of running past the piston rings and deluting the oil, or in extreme cases, igniting off in the oil pan. If you are left with no choice but to use starting fluid in a glow plug or air heater equipped engine, do yourself a favor and disable those items by unplugging them or removing the fuse.