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Z920A - Ever heard of this happening before and some other amateur questions

Discussion in 'Lawn Mowing Equipment' started by sbj333, Feb 22, 2013.

  1. sbj333

    sbj333 LawnSite Member
    Messages: 1

    Hi folks,

    Just bought a 2010 Deere Z920A (54 inch deck). Monster’s only got 130 hours on it – ready for the grass to start growing and to fire her up! Anyhow funny story about the mower – dealer took her back from the first owner do to a blown head gasket. Strangest story though – seems mower was used by a church/cemetery - during the winter layup a mouse set up house keeping in the engine and when they fired it up in the spring mouse condo caused the engine to overheat and thus blow the head gasket. I trust the dealer and don’t doubt them – and I’m an amateur on the mowing thing – but has anyone ever heard of something like this happening before? I thought it was a pretty off the wall.

    Additional question(s) – I’m going to be using the mower in Tennessee to mow the yard part of a little hobby farm I have – will be mowing about 3 acres – level ground with a house and a couple of other small obstacles. I’m currently mowing with an x300 (which is a great little garden tractor - keeping it!) and it’s taking me about 3 to 4 hours – how much quicker do you think I’ll be able to do it with the Z920? Lastly, I have to travel down there to mow so I mow on about 10 to 12 day intervals – folks who know Tennessee mowing – what blades should I run on the zero turn?

    Thanks in advance for your responses - Mark
  2. rreyn1812

    rreyn1812 LawnSite Senior Member
    Messages: 444

    My experience in going from a tractor style mower to a zero turn mower will cut your mowing time roughly in half. I would either use the standard JD blades or go with the Oregon G6 blades (preferred) if they make them for the Deere.
  3. pugs

    pugs LawnSite Gold Member
    Messages: 3,025

    Yah mice can build nests. Not sure I have seen one cause overheating but its possible I guess. I would think its more likely the church never opened it up to clean the cooling fins out and thats where the "mouse nest" came from. I dont see many blown headgaskets here. Usually the head gets too hot and one of the valve guides moves in the head causing the valve to stay open or not open or other issues in the valvetrain due to the valve not being able to move its full range.

    As for mowing, before we started selling commercial ZTRs we had a JD 420 with a 60" deck. It took us about 1:45 to cut our grass. With a 60" ZTR we can do it in about 45-50 minutes. I have also done it in the 45-50 minutes with a 52" Wright Stander. It really depends on how many obstacles you have and how fast you can go due to growth(we have alot of obstacles). We had some spots that the 420 would bog down(force to slow down) on because they grew thicker/faster while a commercial ZTR just chews through it and keeps going at whatever speed you want.
  4. Ridin' Green

    Ridin' Green LawnSite Fanatic
    Male, from Michigan
    Messages: 17,630

    You better believe a mouse can and will build a nest in the engine under the shroud/cowling. My neighbor has a GT he keeps in his shed over the winter and every spring we check it and end up blowing a ton of crap out of it. Easily enough to overheat an engine in no time.

    If the 920 has a standard deck, use the G6's. IME, a ZTR doesn't cut down on time as much as most guys here try to claim, but this is a lawn care forum, so you have to expect it since that's what most of us mow on to make our living.
  5. 44DCNF

    44DCNF LawnSite Bronze Member
    Messages: 1,563

    The flywheel has fins which move the air across engine areas close to vital internal components to cool them. The shrouding directs the air in, through, and out, as needed. When a nest is built under the shrouding or between cooling fins on heads it blocks airflow, and the effect is hot spots in the engine, which in turn does the damage to internal moving parts. It is much like a bug filled radiator on you car will reduce it's through airflow and it's cooling capacity, leading to overheating.

    It's a good idea to remove shrouds annually or more frequently to make sure it is all clean underneath. Regular maintenance should include blowing compressed air up under shrouds to clear them of built up debris. If you see materials like string, tarp material, fabric, and other debris that would not typically be sucked in during lawn maintenance, disassemble the shrouding and check for nests. As well as nests, oil leaks can become covered in dust and grass clippings and reduce cooling capacity. In dusty conditions they may be covered with so much oil absorbing dirt that you do not notice you have a leak. Another reason it is good to regularly blow engines clean and/or remove shrouding to clean under them.
  6. weeze

    weeze LawnSite Fanatic
    Messages: 12,569

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