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743b bobcat wont start

CASE1234

Well-Known Member
Joined
Jul 13, 2016
Messages
100
Location
MISSOURI
went and looked at this 743b bobcat . started fine, everything functioned as it should. no oil leaks. so guy delivers it. starts right up, unloaded it and drove it to the canopy by the barn. I am completely new to bobcat. next morning went to start it. no go. not even a puff of smoke. turns over fine. did notice fuel gage was low so I added 5 gal of diesel. venedt the fuel filter and it was full. primed the bulb up till is was hard, start. I manually opened the shut off valve which I think is air but still no start. so if anyone can steer me in the right direction I would appreciate it. I had the bar all the way down when I tried to start. thanks for reading, norm
 

thepumpguysc

Senior Member
Joined
Mar 18, 2010
Messages
7,445
Location
Sunny South Carolina
Occupation
Master Inj.Pump rebuilder
Why not call the guy that delivered it?? {not trying to be rude} there must be a "special" button your not pushing..
Does it have glow plugs?? are u activating them??
 

CASE1234

Well-Known Member
Joined
Jul 13, 2016
Messages
100
Location
MISSOURI
Kubota 4 cylinder engine?
it is a Kubota 4 cyl diesel. on the left hand side of the motor on back of it there is a canister that operates something when you turn the key on. is that a air shutoff valve to kill the motor. thanks
 

mg2361

Senior Member
Joined
Jul 5, 2016
Messages
5,060
Location
Pennsylvania
Occupation
Equipment Mechanic
Fuel shutoff cable or electric (key) off? Also check the seal under the bleed screw on the filter.

Kubota.png
 

Vetech63

Senior Member
Joined
Aug 10, 2016
Messages
6,362
Location
Oklahoma
I have never seen an air operated shutoff on a bobcat, it’s more than likely an electric shutoff solenoid. If I were you I would start with bleeding the fuel system since it was running with low fuel in the tank.
 

CASE1234

Well-Known Member
Joined
Jul 13, 2016
Messages
100
Location
MISSOURI
looks a though the fuel shutoff isn't working correctly. it doesn't open with the key but if you turn the key on and manually open it it will stay open. don't feel a click on it when the key is turned on. does click and close with the switch off.
 

willie59

Administrator
Joined
Dec 21, 2008
Messages
13,363
Location
Knoxville TN
Occupation
Service Manager
A 743B is has a pre-combustion chamber ignition Kubota engine, those things required glow plugs to start when they were brand new. With age, as would be any 743B now, you most definitely need glow plugs to make it fire off. They won't hit a lick if the glow plugs aren't working or are not being activated.
 

Ronsii

Senior Member
Joined
Jun 26, 2011
Messages
3,464
Location
Western Washington
Occupation
s/e Heavy equipment operator
& on some, the solenoid isnt activated until the key is turned to run the starter..
Yep, so if someone added a button (and overused it) the plugs may not be in working order anymore.... simple to test any part of the GP system, all you need is a DMM.
 
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