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Kawasaki 25hp FH721V - "Texas Flood"

Discussion in 'Hustler Turf Equip (Archived)' started by MJfromMD, May 5, 2013.

  1. MJfromMD

    MJfromMD LawnSite Member
    Messages: 29

    I know my Hustler Z is now considered old and has even been discontinued. But I bought it new in 2008 and it has been fantastic as a lawn munching machine. It only has 160 hours on it. Admittedly, I originally wanted the Kohler power but was talked into the Kawi by the dealer who sold it to me. AND Honestly - it had proven to be a nice reliable, powerful, and efficient engine, (although it had some tiny quirks which I won't mention in this post).

    However, yesterday it really hurt me while mowing. It "cut out" for no apparent reason. History had taught me that the fuel filters on these rigs were a tad too small, (and I had run this one since last season) so being near my garage I installed a new one. I had done my pre-season maintenance on schedule but left out that filter change because I was out of them. But I had bought one since and so I threw it in. Thinking that it would fire right back up after a 30 minute rest, I was surprised when it wouldn't - and evidence of fuel flooding caught my attention.

    I took off the air snorkel tube to have a look and the entire carb base was full of gas. I mopped it out, dried it, re-assembled it and fired it up - only to have it run 5 seconds, then "die" with the same results. I did this 2 more times to get it under cover (in my mower garage) then went home, got my back-up mower, and finished the other 3 acres of mowing.

    When I decided to look into it I was horrified to see the crankcase was now full of gas too. I drained it all out and disassembled enough to remove/inspect the carb. What I suspect is that the float valve is stuck open and the fuel cut-off switch is the only way I stopped the entire tank from siphoning into the engine. I don't want to hear about the fear of Ethanol since the Kawi manual for the engine claims 87 octane @10% Ethanol is expected.

    I was lucky it didn't run on - and destroy the engine by locking up - or some other catastrophic mess. I plan to rebuild the carb, but I also bought another used one off of eBay to hedge my bet. Besides that - The two screws holding on the bowl of the original carb are so damn tight, I was unable to remove them as yet. So it will be a special project to take on - probably at a later date. For the present, I plan to clean up and use the eBay carb when it comes in.

    All I can say for now is, this shouldn't happen. Reading some forums I saw where this is not any rarity in occurrence. That's scary for a relatively newly designed engine. Especially since I have an old Husqvarna with a 22 hp Kohler that is pushing 500 hours now, all without any engine-related issues. As a matter of fact, no engine I have owned has pulled such shenanigans.

    I know most of you are commercial folks with much more equipment and experience with such. But personally - I think it's a bad design allowing such to threaten a $2200 engine. I just posted this here because this forum has helped me with a lot of great information - and proven an excellent source for genuine technical assistance not offered by equipment dealers. So perhaps this may somehow help someone else with similar symptoms. For what it's worth.
  2. Sharpcut 1

    Sharpcut 1 LawnSite Senior Member
    Messages: 452

    Make sure you replace all O-rings, as the ethanol makes them swell, and will contribute to the condition you speak of. More times than I care to admit, I have had to take a small vice grip to those screws to get them out. Also, if you take the jets out (You should) there are O-rings around them also, but the left and right sides are different to acount for differences in the intake runner lengths. Make a note as to which one comes out of which side for reassembly. You'll find one really funky looking O-ring around the jets, real thin a kinda shaped like a bowtie. Watch that little sucker!!
  3. MJfromMD

    MJfromMD LawnSite Member
    Messages: 29

    Thanks to your reply. I found that the float sticking was evidently the only problem in the carb thus far. After dis-assembly/re-assembly and a few insurance replacements of related items that weren't actually defective - I have the engine resumed in its routine operation.

    I performed compression/leak-down tests as well, just to get a base line and make certain that other subtle issues weren't lurking. The machine is actually again running fantastic and continues to amaze everyone around here with its abilities and fine cutting.

    One thing worth noting to all is the issue constantly raised concerning ethanol in the fuel. Yes - it has performance degrading properties and it attracts water molecules among other things that we all hate.

    But the Kawasaki manual for this engine states that fuel of 87 octane and 10% ethanol is both compatible and acceptable. That says to me that the materials used in manufacturing this engine were selected with this in mind. So if it causes early failures, the manufacturer is to blame, since they are saying that this fuel we all have to burn now days is fine with their engine.

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