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Thin wrench size for fuel shutoff solenoid

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lotsagrass

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Discussion starter · #1 ·
Are those screw in fuel shutoff solenoids almost all using the same wrench size? 1/2" ? I keep hearing people in youtube videos mention they grind down a 1/2" wrench to remove these but I plan on buying a set of thin wrenches so I don't have to ruin any of my good tools. Is it truly a 1/2" wrench size (no metric)?

Also, the reason for my question is because I think this solenoid is what's causing a sporadic shutdown of my engine as I'm mowing now and then. If I fiddle with the fuel shutoff solenoid like move the wires/connection or twist the solenoid slightly, the engine usually starts right up. When it dies, it sound like someone just shut off the fuel. It dies very quickly. This is on a John Deere mower that has a Kawasaki FX921V-AS10 engine, but since Deere apparently doesn't let most third party sellers online sell parts for Deere products (even though this is really a Kawasaki item), I believe the part number Kawasaki 21188-7003 will work. When I research that part for the FX921V engine, it fits a wide range of FX921V engines but the FX921V-AS10 version is conspicuously missing in the list (the version Deere uses on their mower). I thnk it's the exact same thing but just checking wiht you all. The part is around $165 if you buy the Deere part number but it's only $65 if you buy the Kawasaki 21188-7003 part number.

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#2 ·
lotsagrass said:
Are those screw in fuel shutoff solenoids almost all using the same wrench size? 1/2" ? I keep hearing people in youtube videos mention they grind down a 1/2" wrench to remove these but I plan on buying a set of thin wrenches so I don't have to ruin any of my good tools. Is it truly a 1/2" wrench size (no metric)?

Also, the reason for my question is because I think this solenoid is what's causing a sporadic shutdown of my engine as I'm mowing now and then. If I fiddle with the fuel shutoff solenoid like move the wires/connection or twist the solenoid slightly, the engine usually starts right up. When it dies, it sound like someone just shut off the fuel. It dies very quickly. This is on a John Deere mower that has a Kawasaki FX921V-AS10 engine, but since Deere apparently doesn't let most third party sellers online sell parts for Deere products (even though this is really a Kawasaki item), I believe the part number Kawasaki 21188-7003 will work. When I research that part for the FX921V engine, it fits a wide range of FX921V engines but the FX921V-AS10 version is conspicuously missing in the list (the version Deere uses on their mower). I thnk it's the exact same thing but just checking wiht you all. The part is around $165 if you buy the Deere part number but it's only $65 if you buy the Kawasaki 21188-7003 part number.

View attachment 383407

View attachment 383408
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In my opinion, I would remove the old solenoid. Cut the pintle off and reinstall it. As long as your ign grounding system is intact, your engine will shut down when required.
 
Discussion starter · #3 ·
Walker56 said:
In my opinion, I would remove the old solenoid. Cut the pintle off and reinstall it. As long as your ign grounding system is intact, your engine will shut down when required.
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I was thinking about doing that also. The ONLY reason I was thinking about buying a replacement (if it's bad) was to keep gas from continuing to flow after I turn off the key which might cause some extra fuel in the cylinder and a little hard start or puff of smoke on the next startup (or even a backfire at shutdown). For whatever reason, this engine has always been a little finicky to start immediately even since brand new compared to my last mower (which had a Kawasaki FH770D)...and it has also been known to blow a little white smoke at startup now and then, but not nearly as often since I started shutting it down at high throttle (expels any leftover fuel from the cylinders after I turn off the key...but not as well if I snip the tip off the solenoid).

I suppose safety is also a good reason (I assume that solenoid will be triggered if the seat sensor is not closed (nobody on the seat) and that could happen for example if you flipped the mower (God forbid).
 
#4 ·
lotsagrass said:
I was thinking about doing that also. The ONLY reason I was thinking about buying a replacement (if it's bad) was to keep gas from continuing to flow after I turn off the key which might cause some extra fuel in the cylinder and a little hard start or puff of smoke on the next startup (or even a backfire at shutdown). For whatever reason, this engine has always been a little finicky to start immediately even since brand new compared to my last mower (which had a Kawasaki FH770D)...and it has also been known to blow a little white smoke at startup now and then, but not nearly as often since I started shutting it down at high throttle (expels any leftover fuel from the cylinders after I turn off the key...but not as well if I snip the tip off the solenoid).

I suppose safety is also a good reason (I assume that solenoid will be triggered if the seat sensor is not closed (nobody on the seat) and that could happen for example if you flipped the mower (God forbid).
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As long as your key is in the run position, the solenoid will have power and the pintle will be retracted. So, if you were to vacate the operators seat for any reason, the coils would ground and kill the engine but the solenoid would still have power and be retracted as long as the key was on.
 
Discussion starter · #6 ·
Walker56 said:
As long as your key is in the run position, the solenoid will have power and the pintle will be retracted. So, if you were to vacate the operators seat for any reason, the coils would ground and kill the engine...
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Ah, good point. So the only meaningful reason (for me) for the fuel shutoff solenoid would be to keep unwanted fuel from sneaking into the cylinders after the key is switched off. Taryl Dactal on YouTube (Taryl Fixes All channel) refers to the shutoff solenoid as an 'anti-backfire solenoid'...so knowing the engine will be killed anyway if you're off the seat because of the coils getting grounded, that makes sense why he refers to it as that.
 
Discussion starter · #7 ·
crankincraig said:
1/2 inch (.500) wrench is very close to 13mm (.512) and works in most applications.
9/16 and 14 mm also very close.

A standard wrench would work on those two anyway.
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Ok, thanks. There's a set of thin specialty wrenches on Amazon for around $25. Sizes: 3/8" x 7/16", 1/2" x 9/16", 5/8" x 11/16", 3/4" x 13/16",
7/8" x 15/16", 1" x 1 1/16", 1 1/8" x 1 1/4".
 
#8 ·
lotsagrass said:
thnk it's the exact same thing but just checking wiht you all.
Click to expand...
It is.
Most all are 1/2" wrench size. I use a thin tappet wrench, but also have a couple ground down wrenches.
If you clip it, just idle down a bit before u kill it. Can also stop it with PTO engaged.
 
#12 ·
Anti after-fire solenoid , what fun is that. I used to love it when they would shut off and someone was there that did not expect the delayed backfire.
Just like an older car with a carburetor and not fuel injected; leave it in drive , shut off the key and coast for a little and then turn the key back on. In my teen and early twenties I was putting on a new muffler every week. Not to mention a couple sets of rear tires to go with it.
 
#15 ·
I have several sets of thin wrenches and none of them were thin enough to fit the solenoid. Just plan on buying a cheap 'sacrificial' wrench and grind it down.

Also, its better let most all Kawasaki engines 'idle' (cool down) a bit before turning them off. They are bad about 'heat soaking' your coils...which shortens their life appreciably. Not always possible to let them cool down...I understand, but if you can..your coils will last longer.
 
Discussion starter · #17 ·
Well the deed is done. My thin wrenches arrived today (the correct size is indeed 1/2" - best fit). I sawed off the rod and put the solenoid back in the carb. If it doesn't die unexpectedly the rest of the season I'll assume that was the problem and just to keep it 100% stock and proper, I'll buy a replacement solenoid this winter and replace the one I cut off.

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#18 ·
lotsagrass said:
Well the deed is done. My thin wrenches arrived today (the correct size is indeed 1/2" - best fit). I sawed off the rod and put the solenoid back in the carb. If it doesn't die unexpectedly the rest of the season I'll assume that was the problem and just to keep it 100% stock and proper, I'll buy a replacement solenoid this winter and replace the one I cut off.

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You wont have any issues. It is done all the time. Happy Mowing
 
#19 ·
on my crapsman with the kohler I cut it off and as long as you let it idle down and cool for a minute before shutting off it don't backfire ,as it cools the metal in the muffler and gets rid of the excessive fumes, key it off without a cool down , you get a loud ask Bang , the Onan ( n52m) does it also , its states in my owners manual to idle it down for a minute or two before shut off . I use it for my one neighbor ho complained I didn't start early enough on the lawn , full throttle a little choke and key off and on . sounds like s 12 ga .
 
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