Having trouble with my Bobcat 763, suspect it might be glow plugs and injectors but was hoping for some guidance. After a starter and fly wheel replacement had the thing up and running fine for a bit than during a load with the bucket it just started to loose power and and turn off. I was able to give it a minute and a few start try's and it started back up and ran until my job was complete. This seemed to happen the last few times I ran it until now it stopped and won't start up again. Outside temp has been in the 50's I suspect alternator and/or battery are going to need to be replaced soon, but don't think that is the problem at this time to not get it started since it cranks fine just doesn't turn over. Thought it was a low battery and after charging to full still would not start. A hit of starter fluid in air intake gets it to turn over briefly but feels like it's not getting fuel to stay running. no codes on the display except b-22 after trying to start for a bit, which I believe is the battery voltage. New fuel and tank is full. Fuel Primer bulb is very stiff and hard to depress (not sure if that's normal) I don't have a service center nearby to get parts from so need to order online, just hoping to narrow it down before hand.
BobCat 763 Won't Start
- Thread starter jsipaila
- Start date
I would start by checking the fuel shut off solenoid. I would tie it in the run position to try it. Next I would verify fuel flow. The primers get hard with age running hot water on them softens them up. Pump and make sure fuel flows and pick up tube is ok otherwise try out of a fuel can. Also check I believe there is a speed sensor on the flywheel that maybe isn't adjusted right after previous repair. 50 degrees shouldn't need glow plugs.
The primer loosened up once it warmed up a bit more and I disconnected the fuel line to the pump. I replaced the pump but still not getting it to start, I still don't think fuel is getting through the pump. Setup is fuel tank to hand pump to fuel pump to fuel filter to another valve (not sure what it is called, but has a knob that can be turn about 180 degrees left of right, assume right is open) from here it looks like it feeds the injectors. I circled it with a red circle if you can get to the photo https://photos.app.goo.gl/Ty5BuciS82gkhL5C9 When I disconnected the fuel line to the pump I was able to get a gravity drain of fuel through the valve. Disconnecting the line from the pump to fuel filter and trying to run nothing comes out (same with the prime (hand) bulb pump) Not sure where I would locate the speed sensor. The way it was acting it feels like it's just not getting fuel.
flyerdan
Well-known member
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- Mar 7, 2009
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- 983
Any time a diesel starts to lose power, the first thing to check is the fuel filter, it could be algaed or waxed up. Bobcats are also notorious for breaking the pickup line in the tank; it can be a crack or full break that allows air into the system with plenty of fuel left on the gauge.
The valve you have circled on the pic is the bleed valve for getting air out of the system when you change filters. It's just before the injector pump so you don't get air in that which would require loosening the fuel lines at the injectors to bleed it out. Since you've replaced the pump, open the valve and squeeze the bulb until you get bubble-free fuel out of it. Hopefully that will sort it, but I suspect that you'll have to bleed the injector lines due to trying to start it without a fuel supply feeding the injector pump.
The lift pump will not let fuel gravity flow. If you take hose off from fuel filter and pump the primer do you get good fuel flow? You can unhook fuel line and put it in a can of fuel you could have a plugged or cracked line
When I disconnected the line to the fuel pump and used the primer it was flowing some fuel out that way. I can hear it squirting in the line when pumping but the fuel never seems to get past the fuel pump or build up pressure after the primer pump (30+ pumps and still can squeeze and no fuel into new fuel filter), I'm thinking that might have gone bad at this point and the check valve isn't doing it's job? I replaced the fuel line from the primer pump to the fuel pump. I haven't had a good look at the tank to primer line, not quite sure how to access that one with "ease".
Honestly, i'd start by eliminating a few things. Get a new hand primer and some fuel line.
Get a fuel can full of diesel, hook up a line to the can, to the primer then into the lift pump that goes to the injector pump. This will emininate the pickup tume and hydraulic fuel filter, so ENSURE the fuel can is clean clean clean.
Prime it, and start it, even wire the can of fuel somewhere that you can work it, see if the issue is still there. If it's good, replace the fuel filter and all lines to the fuel tank, even the pickup tube and pickup screen inside the tank.
Wanted to give a quick update on this, I was able to get it working. Turns out it seemed to be the bulb primer that was giving me issues, once that was replaced was able to prime the fuel intake. On a side note from my picture, the turn valve at the top seems to be a fuel shut off instead of an air purge like I originally thought. Had to keep it all the way left for the bob cat to keep running. So replaced the fuel pump, filter and bulb primer and all is good again. Thanks all for your suggestions.
