Hey guys. Ideas on what to check for low power situation. I'm pretty sure it's fuel related. Machine lost power, changed fuel filter. Seemed to be ok for awhile, then same thing. Another filter change, still didn't run properly. Changed primer bulb, blew back to tank. Ideas??
When you say loss of power, you're saying the engine stalls out kind of power loss?
Hey Willie. I would have "tagged" you if you could do that here. Yeah, no power, no smoke. The guy managed to get it up by the shop, let it idle for a bit, ended up dying out.
Well, it could be a faulty lift pump, but we gotta fix something else first. Most likely cause is pick up tube in the tank, common Bobcat problem. But if you blew compressed air back in tank line, most likely the pick up tube is no longer there. Bobcat uses a screen with a check ball on the end of the tank pick up tube, don't blow compressed air into that line. You need to pull the pick up out of the tank and replace components as needed. When you do this you may find your problem is fixed. Here's a thread with some information that you need. >
Hey Willie. I misunderstood the guy. He said he blew back, but upon further questioning, he did not. So, I had him connect a length of clean line to the line back to tank (after he removed the primer bulb) and try and blow with his mouth. He says he can't blow any air back. What next? Are there any screens in the transfer pump fittings?
Ok, does it stall out fairly quickly, like right now in it's current state? Like, start the engine, full throttle, leave the parking brake on and ease into the brake, once you're locked in push the drive levers forward and put load on the engine. If you can make it stall out like this, preferably until the engine dies out, right then check to see if primer bulb is sucked flat. If it is, screen on end of pick up tube is clogged. If it's not sucked flat, likely fuel line sucking air or faulty lift pump. Disconnect fuel line from inlet of lift pump, connect a piece of fuel hose to it and drop it in a can of clean fuel. Repeat engine loading procedure and see what happens. BTW, someone hasn't opened that bleed valve on the injection pump have they? That will make one run goofy.
Ok. Can check more in morning. I'm diagnosing on the phone currently. I know the primer doesn't suck.flat. I asked that ? already. Not sure about the bleed valve. When he changed the filter the first time, he had a hell of a time getting it going. I suppose I could use a little more in depth info on the bleed screw. Next question, any way to diagnose lift pump? I'm sure they are pretty cheap, might just tell him to change it. Machine only has 1900 hrs.
Well, when your talking about a 753, is it a C, F, or G series? If it's a older model, does it have a spin on fuel filter, or does it have that Stanadyne filter with a drain bowl fitted to the bottom of it?
Spin-on filter. Sorry about taking long to reply. I'm planting right now. I'll pay attention now.
24 row 30 inch. 135 acres since 6 pm.
No problem. The bleeder valve is a knurled knob on the return line fitting on the injection pump. The process, change fuel filter, open bleeder valve on fuel filter base, squeeze primer bulb to fill filter until fuel comes out of the bleeder valve on fuel filter base, close bleeder valve. Open bleeder valve on injection pump, squeeze primer bulb several times to purge air from injection pump, close bleeder valve on injection pump. That's the procedure when changing fuel filter. If one leaves that bleeder valve open on the injection pump it will make one run goofy. There's no definitive way to test the lift pump. About the only thing you can do is connect a fuel hose from a fuel can to the lift pump and see how it works, that is if you can make the engine stall out just sitting in the garage. Kind of hard to do with machine in operation.
Thanks Willie. I'm going to stop out there in the morning and spend about 20 min. I'll let you know what I find. Thanks.
I would be willing to bet the money and hours saved by people by using the information shared on this Forum could number in the tens of millions. Thank you, Willie. After dropping a line in a can of fuel, the pickup tube definitely was assumed to be at fault. After pulling out of the tank, and no line attached at all, it was a known certainty. My buddy says, "Shall I go get my rubber magnet to try and fish that broken line out?" I almost choked. Too bad though that no Bobcat dealer within 150 miles has a tube on hand. Once again, Thanks, Willie.
Rubber magnet...damn that's funny. That's crazy that your Bobcat dealer doesn't have that stuff, heck I even keep some of the tubing, the clamps, screen with check ball, grommet, and elbow fitting on my truck, and I ain't even a Bobcat dealer, it's just a common problem with Bobcat machines. :beatsme In a pinch you could use clear vinyl tubing, but it won't last long in the diesel tank and will break again. The tubing that Bobcat uses is Superthane ester tubing, more resistant to oil and fuel. Good to hear you sorted it out anyway. :drinkup
Hey Willie! Need your help again! Interlock won't release. Dealer told my buddy to change the solenoid. Did that, still nothing. I haven't asked him if he has hydraulics. Will do that right now.
Now I definitely need to know if it's a C, F, or G series 753.
Sorry. I'm back. No idea about the series. Any dead giveaways? It does have hydraulics, so it's not the drive belt.
C series: rectangle shaped headlights. Two piece rear door, mostly orange color with a black colored piece mounted at the top of the door F series: rectangle shaped headlights. One piece stamped steel rear door, all orange G series: triangle shaped headlights
I'll ask.
Sorry. C-series. I thought it had triangle headlights.
Bump.
Sorry, I've been busy as a one legged man in a butt kicking contest, both at work and at home, getting things sorted out to go on vacation. When you say "interlock", I assume you're talking about the traction lock since you mentioned it does have hydraulic functions. On a C series, they have, at best, a very basic diagnostic system for the BICS controller, think of OBDI on vehicles back in the 80's, very elementary and basic info. When you start the engine, let the seat bar down, and press the push to operate button, are all of the LED lights on the BICS controller lit up? If not, which one is not? Are any of them flashing?
K. Where is this controller?
On a C series, the BICS controller is on the back wall of the cab on the right side of the seat (right side as you sit in the seat), has LED lights on it. With engine running, seat bar down, and press push to operate button, are all lit up?
I'll have to wait until tomorrow morning to check. If a light is not lit or blinking that indicates an electrical problem?
Called my buddy. When he has it running, bar down, pushes button, the second light from the bottom stays dark. Convenienly enough, he says that's the traction light?
Then you don't have a problem with the traction lock solenoid as the dealer suggested, you have a problem with either the seat bar sensor or the (arse planted in the) seat switch. The seat switch was problematic on those machines, but first make sure there isn't something under the seat preventing it from moving to activate the seat switch. If still no joy, start engine and leave seat bar up, then press the "traction lock override" button, see if machine will now drive. If it does, fault with seat switch or seat switch circuit.