Continuing to work out bugs in my newly acquired 1999 bobcat 863. I just recently pulled the motor to replace some items including a new fuel pick up tube,screen and all new fuel lines. I also replaced fuel primeing bulb. I thought I was ready to put it to work but after just a few minutes into it it lost power and died. I notice the fuel priming bulb squished. I relieved the vacuum by disconnecting it from the tank side. I thought maybe debris clogged the screen somehow and tried to blow air back into the tank but the new screen/check valve wouldn't allow that. After reconnecting the fuel line I tried to prime the filter, it did but the bulb was slow to reform. It ran for a short while then died again from lack of fuel. My question is what are my options now? I am not pulling the motor to replace the fuel pick up tube with a different one. Maybe a bad new priming bulb? Not sure how to eliminate the priming bulb. Any help would be appreciated. Thanks in advance.
I wouldn’t assume eliminating the primer bulb will solve your issue. I would use that as a sign that something else is wrong. I have seen plenty of old (hardened rubber) primer bulbs be crushed and not retake shape, however it sounds that you have a new one on your machine. I assume you know this, if you have the skill set to pull the motor, so forgive me if I’m explaining the obvious. When your Engine is running, it’s drawing fuel through what I’d assume is a vacuum pump off crank pressure (unless someone upgraded to an electronic pump). So as your engine runs, you’re pulling (sucking) fuel. You can only suck out of a sealed system so long before the weak points start collapsing (your primer bulb- weaker than your fuel tank). What I’m getting at is; remove your fuel cap and eliminate this from the equation. Tank will not be sealed closed for sure then. If still having an issue- Next you could wrap a cloth around the cap hole and use air pressure to see if this will blast any debris from screen. If still having an issue. Pull fuel line before or after primer bulb. If before, fuel should run out if gravity fed. If after, you should be able to use primer bump to pump fuel into a bucket many times with the bulb retaking shape each time. Should be a minor issue with all your lines being new. Good luck
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Does your pick up tube have a check valve?
Yes the pick up tube has a check valve
Yes, a brand new one. I wish I would of just put the tube in a put a check valve filter near the priming bulb
Okay, so if you’re priming the bulb and pressure is achieved, wouldn’t that mean the bulb would stay compressed until the pump kicked off. I put my check valve after the bulb.
I don't think so. Fuel should flow freely through the bulb. I believe there is a check valve on the output of the bulb so fuel doesn't flow back in bulb. Check valve in filter at the fill tube in tank to keep line full of fuel so no priming needed. So maybe my idea won't work. Either way I think somehow my new fuel pick up tube filter is blocked. The 863 is such a pain to do minor maintenance.
Very good explanation for people who have not thought outside the box. Simon C
I tried removing fuel cap, disconnected fuel line from filter block. Tried to pump fuel out. Since it had been sitting awhile I pumped a little out then it stopped with primer pump flat. I think it all points to clogged fuel pick up tube filter. The thing is I recently drained all the fuel from tank from bottom plug. (By accident). So hard to belive it clogged so fast.
Hook up a pail vacuum set up and vacuum the bottom out of the tank with a hose or skinny pipe. Use a white pail or yellow one so you can see what kind of junk is down there. If any Dirt comes up it would be a good idea to either blow bottom of tank to churn up the dirt then suck out, or tank out and flipped upside down to get it all out. Simon C
I would of thought 15 gallons rushing out of the drain would of flushed it out pretty good. Either way it looks like i am going to have to at least raise the engine to get underneath to remove pick up tube and filter. May remove screen and prefilter before or after primer bulb. Was just hoping for other solutions
Classic Bobcat problem, strainer screen on end of pickup tube inside the tank is clogged with debris, I've seen it seems like a gazillion times. And depending on the model, some are a PITA to access and remove the elbow fitting on top of the tank that has the pickup tube attached to it. And...the fuel return has the same elbow fitting on it, so you have to make sure you're pulling the pickup tube fitting and not the return fitting.
Have you tried blow air back into tank, to clear the pick up screen? It has a check valve, so may not work.
I had a new holland act in a similar way- it did not have a primer bulb. I flushed the tank with an electric pump twice. I would start the machine and after 10-15 min it would die and starve for fuel. Turns out there was a small piece of debris getting caught and clogging pickup, but not small enough to get through and caught in filter. Even with flushing the tank twice I didn’t get it. Third time I got it. I was shocked, but happy it was a simple fix. With bobcat often having the fine strainer screen, signs certainly point to that being clogged. Air may blast it free a few times, but you likely will eventually need to flush tank. Can you flip the cab and completely remove the tank to flush it thouroughly?
If you try compressed air back in the supply line of a Bobcat you'll only blow the pickup tube off of it because of the check ball in the screen strainer at the end. The only way to remedy this problem is to remove the pickup tube. And since you have it out, put a new tube on it as they wear out from fuel exposure. If there's sufficient debris in the tank that keeps this problem coming back, the only thing you can do is run it as low on fuel as you can and remove the plug in the bottom of the tank and hope the debris comes out.
Agree with the above, however I was referring to blowing air in the tank via the fuel cap point. To agitate the fuel. Likely not a solution, but sometimes scatters debris.