bobcat 632 shutdown

dacott · Apr 8, 2009

Starts and runs fine for 10-15 min. then stumbles and shuts down. Cycle the key and usually starts back up, runs a short time and stops again. Acts like no fuel but is full and the gas filter is less than 2hrs old. Any help? Also, what is the carb solonoid for that is shown on the diagram. thanks

Tazza · Apr 8, 2009

Check the routing of your fuel lines too, if its too close it could be vapour lock in the lines.
I don't know how the solenoid works thats on te carb, but i'm sure someone will pop their nose in and tell you.

Skiddy · Apr 8, 2009

Tazza said:
Check the routing of your fuel lines too, if its too close it could be vapour lock in the lines.
I don't know how the solenoid works thats on te carb, but i'm sure someone will pop their nose in and tell you.

There is a solinoid inline that shuts the fuel flow off when the key is off. Those are easy to check. Sounds like I would check your intank filter and hose first.

mrfixitpaul · Apr 9, 2009

Skiddy said:
There is a solinoid inline that shuts the fuel flow off when the key is off. Those are easy to check. Sounds like I would check your intank filter and hose first.

The solenoid on the carb is to prevent run-on when you turn off the engine. It blocks the main jet when key is turned off. If it goes bad usually you won't even start.

jerry · Apr 9, 2009

mrfixitpaul said:
The solenoid on the carb is to prevent run-on when you turn off the engine. It blocks the main jet when key is turned off. If it goes bad usually you won't even start.

My 632 was doing the exact same thing about a week ago. checked the fuel flow to the pump and it was fine pump pressure was about 2 lb. I removed the carb solenoid and it made no difference. tried a different coil but it was a old coil and did not work so I connected the bobcat coil up again and the thing ran perfect. I thought with the low fuel pressure I should replace the pump so $82 later I did. Then with the proper fuel pressure and no solenoid when I shut it off the remaining pressure bleeds by the needle in the bowl and floods the engine so today I put the solenoid back in and it seems o.k. now. I think the thing would run good with no fuel pump and no solenoid as the tank is above the engine. My trouble is in the coil wiring somewhere there must be a partially broken wire or maybe a bad condenser. I can't find it now so I will wait till it happens again. I think your problem is electrical also. If you have two people when it is doing the starting and dying thing set it up so someone can watch to see if the spark quits as it dies. If you figure it out please post it here.

dacott · Apr 9, 2009

jerry said:
My 632 was doing the exact same thing about a week ago. checked the fuel flow to the pump and it was fine pump pressure was about 2 lb. I removed the carb solenoid and it made no difference. tried a different coil but it was a old coil and did not work so I connected the bobcat coil up again and the thing ran perfect. I thought with the low fuel pressure I should replace the pump so $82 later I did. Then with the proper fuel pressure and no solenoid when I shut it off the remaining pressure bleeds by the needle in the bowl and floods the engine so today I put the solenoid back in and it seems o.k. now. I think the thing would run good with no fuel pump and no solenoid as the tank is above the engine. My trouble is in the coil wiring somewhere there must be a partially broken wire or maybe a bad condenser. I can't find it now so I will wait till it happens again. I think your problem is electrical also. If you have two people when it is doing the starting and dying thing set it up so someone can watch to see if the spark quits as it dies. If you figure it out please post it here.

Thanks to all for your help. This gives me some things to look into. Any other ideas are sure to be a great help also

Skiddy · Apr 9, 2009

dacott said:
Thanks to all for your help. This gives me some things to look into. Any other ideas are sure to be a great help also

when you do finally solve your problem please post up your resolution.

jerry · Apr 10, 2009

Skiddy said:
when you do finally solve your problem please post up your resolution.

I ran ran the 632 a couple of hours today, starting and stopping several times and it works fine. It does seem to start quicker now with the new fuel pump and if you are still having problems take a look at your fuel pump pressure. with the check valves in the pump it may be that it won't let gas go through unless it is pumped through.

dacott · Apr 11, 2009

jerry said:
I ran ran the 632 a couple of hours today, starting and stopping several times and it works fine. It does seem to start quicker now with the new fuel pump and if you are still having problems take a look at your fuel pump pressure. with the check valves in the pump it may be that it won't let gas go through unless it is pumped through.

What should the fuel pump pressure be?

jerry · Apr 11, 2009

dacott said:
What should the fuel pump pressure be?

I think the parts guy at Bobcat said 5 to 7 lbs, my old one would get to 2 lbs after several cranks whereas the new one pops right up to 6 or so. One reason I went to bobcat also was to make sure it had the right pump which it did. sometimes people will try to find a auto pump that will work and maybe they can. also if your pump has a thick shim or gasket [1/4 inch] between the pump and the block be sure to put it on the new one as it positions the arm on the cam in the right spot.

dacott · Apr 13, 2009

jerry said:
I think the parts guy at Bobcat said 5 to 7 lbs, my old one would get to 2 lbs after several cranks whereas the new one pops right up to 6 or so. One reason I went to bobcat also was to make sure it had the right pump which it did. sometimes people will try to find a auto pump that will work and maybe they can. also if your pump has a thick shim or gasket [1/4 inch] between the pump and the block be sure to put it on the new one as it positions the arm on the cam in the right spot.

Well I was sure it was the coil, so I tried another one (not new tho). It started quick and ran strong for about 20 min. then the stumble and shut down again. As before, restarts pretty quickly and runs for a minute or so then does ir again. Sitting still, it will run at a high rpm flawlessley. I am suspicous now of the solinoid on the carb, but I cant see it(is it between the carb and the block) and I see no wire around there that would lead to it. What do you need to do to get to the carb? Do you need to remove the gov. assembly and the distributer? Appreciate any ideas.

jerry · Apr 13, 2009

dacott said:
Well I was sure it was the coil, so I tried another one (not new tho). It started quick and ran strong for about 20 min. then the stumble and shut down again. As before, restarts pretty quickly and runs for a minute or so then does ir again. Sitting still, it will run at a high rpm flawlessley. I am suspicous now of the solinoid on the carb, but I cant see it(is it between the carb and the block) and I see no wire around there that would lead to it. What do you need to do to get to the carb? Do you need to remove the gov. assembly and the distributer? Appreciate any ideas.

the wire may be hidden by crud but it should be there and a clip connector about 6 inches from the carb. I had to take the carb off to work on it which is not a big deal just take the fuel line off at the pump, undo the governor rod at the first joint is easier than at the carb,you will have to take the nut off to undo the rod they do not have a spring release, release the choke wire and take out the two flange bolts that hold it on, one comes down thru from the top of the manifold. when you put it back on do not over tighten them as it is easy to strip the threads out of the carb flange. I had to helicoil one of the bolt holes but I think it was mostly bad to begin with. disconnect the battery also, with all that gas splashed around you don't want any sparks from wrenchs.

dacott · Apr 13, 2009

jerry said:
the wire may be hidden by crud but it should be there and a clip connector about 6 inches from the carb. I had to take the carb off to work on it which is not a big deal just take the fuel line off at the pump, undo the governor rod at the first joint is easier than at the carb,you will have to take the nut off to undo the rod they do not have a spring release, release the choke wire and take out the two flange bolts that hold it on, one comes down thru from the top of the manifold. when you put it back on do not over tighten them as it is easy to strip the threads out of the carb flange. I had to helicoil one of the bolt holes but I think it was mostly bad to begin with. disconnect the battery also, with all that gas splashed around you don't want any sparks from wrenchs.

Thanks Jerry. I guess that will be the next step. Do you know if any of the temp or pressue sensors on the engine or hydaulics will cause a shutdown?

jerry · Apr 14, 2009

dacott said:
Thanks Jerry. I guess that will be the next step. Do you know if any of the temp or pressue sensors on the engine or hydaulics will cause a shutdown?

I don't think the 632 has anything as advance as a sensor related shutdown that I know of. let us know how it turns out.

coreya3212 · Apr 14, 2009

jerry said:
I don't think the 632 has anything as advance as a sensor related shutdown that I know of. let us know how it turns out.

Not to hijack your thread, but I am having similar issue. 825 with perkins diesel, runs for 10 min to an hour then dies due to fuel starvation. I crack the injectors loose, spin the motor with key, get fuel droplets, retighten and it fires up and runs again for an untold amount of time. Through reading the forum, I started at the pick up line, removed and it was in good shape although a clamp seems ot not hold vaccuum , so tighten up and good. Then found that the pickup line was loose at the fitting at the lift pump. Tighten that and figured I had it licked. Same problem. Move to the fuel filter and change it, there are 2 seals on the new one, one for the top and one for the bottom. Only the bottom one came off with the old filter. Havent run it enough to see if I am there yet. One question I have at this point is, when it stalls due to lack of fuel, I can hear a sloshing noise. I am thinking it is fuel from the return line discharging into the fuel tank? Should this be audible? When it stalls and the engine gets quiet, it sounds to me like pressure that is built up bleeding off. Maybe I have it fixed and maybe not, but if anyone wants to huck there 2 cents in, please feel free. Like I said, not trying to steal anyones thunder, just seems like a related problem. Thanks all.

Tazza · Apr 14, 2009

coreya3212 said:
Not to hijack your thread, but I am having similar issue. 825 with perkins diesel, runs for 10 min to an hour then dies due to fuel starvation. I crack the injectors loose, spin the motor with key, get fuel droplets, retighten and it fires up and runs again for an untold amount of time. Through reading the forum, I started at the pick up line, removed and it was in good shape although a clamp seems ot not hold vaccuum , so tighten up and good. Then found that the pickup line was loose at the fitting at the lift pump. Tighten that and figured I had it licked. Same problem. Move to the fuel filter and change it, there are 2 seals on the new one, one for the top and one for the bottom. Only the bottom one came off with the old filter. Havent run it enough to see if I am there yet. One question I have at this point is, when it stalls due to lack of fuel, I can hear a sloshing noise. I am thinking it is fuel from the return line discharging into the fuel tank? Should this be audible? When it stalls and the engine gets quiet, it sounds to me like pressure that is built up bleeding off. Maybe I have it fixed and maybe not, but if anyone wants to huck there 2 cents in, please feel free. Like I said, not trying to steal anyones thunder, just seems like a related problem. Thanks all.

It could be the fuel returning to the tank. I'd think maybe the fuel lift pump is getting lazy or the bleed screw is not fully turned off allowing fuel to return to the tank (depending on its bleeding setup). I assume the primer bulb is not going flat?
If you catch it before it stalls, try pumping the fuel bulb and see if the engine recovers, if so I'd suspect the lift pump.

coreya3212 · Apr 14, 2009

Tazza said:
It could be the fuel returning to the tank. I'd think maybe the fuel lift pump is getting lazy or the bleed screw is not fully turned off allowing fuel to return to the tank (depending on its bleeding setup). I assume the primer bulb is not going flat?
If you catch it before it stalls, try pumping the fuel bulb and see if the engine recovers, if so I'd suspect the lift pump.

I dont think I have a primer bulb? That to me would be a soft plastic bulb that you press repeatedly to charge fuel lines up, right? My lift pump has a manual primer lever on the bottom of it that I can try that. Unless I just dont know where to look for it.

Tazza · Apr 15, 2009

coreya3212 said:
I dont think I have a primer bulb? That to me would be a soft plastic bulb that you press repeatedly to charge fuel lines up, right? My lift pump has a manual primer lever on the bottom of it that I can try that. Unless I just dont know where to look for it.

That won't work, as when the engine is running it will be operating the lift pump. Well that idea is out then

Yes, the primer bulb is a soft rubber bulb you squeeze.

sterlclan · Apr 16, 2009

Tazza said:
That won't work, as when the engine is running it will be operating the lift pump. Well that idea is out then Yes, the primer bulb is a soft rubber bulb you squeeze.

you say itll run sitting still fine? check the float it may be set to high or filling with gas and sinking

bobcat 632 shutdown

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