542B bobcat...won't start

[kyle1!]

Hello, Dad has a 542B Bobcat that wouldn't start one day. It would crank but not start. He had the dealer come and get. They had it for 4 weeks, said it was bad gas (could be dad doesn't use it that much), added an additive and charged $800 . He has used it 2 times since repair and both times (I was there) it was running extremely rich. Now the 3rd time to use it since repair it won't start again..it cranks but won't start. Any ideas as to what the problem is? This is all the info my dad would tell me.

Brian

 

[groundsmgr]

If it is gas carb could be out of adjustment, or need to be rebult. If deisel could be a bad injector.

 

[sawinredneck]

It's gas. Sounds like there is either still crude in the fuel tank, or the way it's being stored lets crud get into the fuel tank! Remember, this new gas is only good for three months or so without stabilizer in it!
It sounds like either junk or, most likely water, is in the fuel system again and it all needs cleaned again! Drain the tank, blow out the lines, clean the carb, start with good fresh gas, add stabilizer and park it so nothing gets on the engine or in the tank!

 

[kyle1!]

More Info

I was able to read the repair receipt. On Nov 11, they rebuilt the carb, adjusted linkages, changed oil/filters and fixed parking brake. That must of not solved the problem because on Dec 12 (yep had the machine a long time) they replaced the ignition module and stated the machine was running low and high but not in the middle. :msp_confused: Next they added some Octane Booster and said the machine was running great.

Like I said earlier dad used the machine a couple of times after getting it back and it was running rich. Now it won't start. Tonight I unhooked the fuel line before the fuel filter and not even a 1/4 quart of gas came from the tank. I'm thinking dad ran it out of gas We added 4 gallons and tried to start it. We tried 5-6 times with choke/ no choke and could not smell gas so I'm thinking it is not getting fuel. It was 1am and didn't have time to mess with it further. Next time I will pull the line at fuel filter again to see about flow from tank and then if it is getting good flow from the tank pull the line at the carb to see if the fuel pump is pumping fuel. Saw...am I on the right track? What is the fuel capacity of this machine? This machine only has 110 hrs on it and is stored in the garage.

Brian

 

[sawinredneck]

Yep, your heading the right way! Try taking the line from the pump to the tank and blow air through it after you check the fuel filter. This will temporarily clear any restrictions in the tank.
It holds 13 gal of fuel and it's a Ford industrial engine so about any auto parts house should be able to get a fuel pump if you need one.
The pump is rated at 3.5-5.5psi so it will be cam driven, fuel will come out in spurts not a steady stream.
But right now it sounds like crap in the fuel tank restricting the fuel line, a bad filter or a bad pump. You just have to eliminate the good parts to find the bad one and they may all be bad?

 

[kyle1!]

Thanks Saw

The fuel filter is new and I bet there is some kind of obstruction from the pump back to the tank or the tank itself. Surely dad had more fuel in it then the 1/4 quart that I drained. The flow was just a trickle when pulling the line off at the fuel filter then it stopped all of a sudden. Almost like a plugged tank vent or cap not allowing air in. The fuel line was pretty soft as well and would not surprise me if it is the original goodyear hose. I will keep you posted to what I find and once again thanks for your help.

Brian

 

[sawinredneck]

Yes, if the fuel line is cracked it could be sucking air not fuel! I also forgot another early Bobcat problem and I am sorry! Depending on how it's set up, the fuel pickup line inside the tank may have fallen off or rotted out! A VERY common problem with older machines with fuel tanks behind the seat!

 

[kr5258]

Yes, if the fuel line is cracked it could be sucking air not fuel! I also forgot another early Bobcat problem and I am sorry! Depending on how it's set up, the fuel pickup line inside the tank may have fallen off or rotted out! A VERY common problem with older machines with fuel tanks behind the seat!

My line inside the tank was cracked where it connects to the fitting. Drove me crazy, would run but would not power up. Replaced the line and in-tank filter, running great again. Mine is not a 542B but it may be a similar issue.

 

[sawinredneck]

Any luck with this yet?

 

[kyle1!]

New machine...taking it slow

With anything new mechanically I order up a service manual and I'm waiting on that. I'll take a peak at it tonight when I'm there dad lives 20miles north of me. With the soft fuel lines I just plan on replacing all of them, plus fuel filter, and any pieces in the tank. It may take a week or 2 to get to it. I will let you know the progress. What size fuel line is it?

Brian

 

[lone wolf]

Did you try pumping the tank out and fresh gas?Maybe water.

 

[kyle1!]

All that I have done is take the fuel line off at the fuel filter and see if it would flow into a pan. A very small amount 1/4-1/2 quart came out then the flow stopped. Added 4 gallons to the tank thinking dad ran it out of gas but even after adding the gas it still would not start. No gas smell when cranking either.That is as far as I got, it was 1am and needed to head home for some sleep. Tonight it is suppose to be -1F so I don't know how long the fingers will hold out in the cold. If I can get the fuel line size I'll pick some up on the commute home change it out and look into the tank pickup tubes. It just isn't getting enough fuel.

Brian

 

[lone wolf]

All that I have done is take the fuel line off at the fuel filter and see if it would flow into a pan. A very small amount 1/4-1/2 quart came out then the flow stopped. Added 4 gallons to the tank thinking dad ran it out of gas but even after adding the gas it still would not start. No gas smell when cranking either.That is as far as I got, it was 1am and needed to head home for some sleep. Tonight it is suppose to be -1F so I don't know how long the fingers will hold out in the cold. If I can get the fuel line size I'll pick some up on the commute home change it out and look into the tank pickup tubes. It just isn't getting enough fuel.

Brian

Pickup screen clogged or if its cold there like you said its frozen can you push it into a heated area?

 

[kyle1!]

It has been a very mild winter here in Iowa and we are just having a quick artic blast the next couple of days so the machine is not frozen. Since my service manual has not arrived can you tell me how to get to the fuel tank? I assume I have to move the seat and undo a panel of some sort?

Brian

 

[lone wolf]

It has been a very mild winter here in Iowa and we are just having a quick artic blast the next couple of days so the machine is not frozen. Since my service manual has not arrived can you tell me how to get to the fuel tank? I assume I have to move the seat and undo a panel of some sort?

Brian

Not familiar with that machine am basing this on general troubleshooting.Do you know where the fuel pump is?You could try blowing a little air in and see if it loosens up .Make sure the cap is off.

 

[kyle1!]

Update

Here is what we did tonight. I pulled the fuel line off before the fuel filter again and this time I had a good stream. No air was blown through the lines. Next I pulled the line after the fuel pump and had my dad crank the engine. Nice spurts of fuel there. Unscrewed the hex plug at the bottom of the carb and have fuel there.

We cranked the engine 3-4 times then pulled the plug closes to the engine door/cover. I would say the plug was damp but not dripping wet with fuel. It was very black/sooty so that confirms it is running rich like I thought. I didn't have any sandpaper but I used a receipt to clean off the electrode. Put the plug back in the plug wire and ground it to the exhaust manifold. The 1st second dad is cranking the engine I don't see any spark, then a weak white spark appears and if you keep cranking the spark seems to jump from vertical to horizontal along the top of the manifold. The spark plugs are new and the ignition module that the plug wires connect to is new. We will get a new set of plugs, Autolite 103 is what is in there, and see if that helps to at least get it to fire. See ya

Brian

 

[kyle1!]

It is running!!! I think we had 3 problems with the machine. The first is my dad ran it out of fuel, second is my dad probably ran the machine with the choke on creating a bug killing smoke screen, and three fouled plugs see number 2. Replaced the plugs and the machine fires on the second cranking. We will add some more gas to it and put some stabil in it. Thanks to those that helped.

Brian

 

[kyle1!]

Dad has let his machine sit again and it won't start again. Cranks but no fire. Because this has to be fuel related I think I'm going to go thru the whole system. The carb bowl was completely dry after cranking (bowl gasket tore)and there is a small leak right in front of the little fuel solenoid (shut off valve?) behind the fuse box on the left side of engine bay. It is a 542b model with zenith carb. I'll replace fuel filter, carb kit, fuel pump and line. Then after that I will keep using it so I don'[t have to keep working with a poor fuel sysetm

 

[lone wolf]

Dad has let his machine sit again and it won't start again. Cranks but no fire. Because this has to be fuel related I think I'm going to go thru the whole system. The carb bowl was completely dry after cranking (bowl gasket tore)and there is a small leak right in front of the little fuel solenoid (shut off valve?) behind the fuse box on the left side of engine bay. It is a 542b model with zenith carb. I'll replace fuel filter, carb kit, fuel pump and line. Then after that I will keep using it so I don'[t have to keep working with a poor fuel sysetm

Was all the old gas emptied from the tank and new tried?

 

[kyle1!]

We pulled the fuel tank and the line inside the tank had fallen off. There was a split in the tube. Still plan to go through the fuel system maybe add an electric fuel pump since I'm sure all the components of the system are original. They have to be getting tired from all the sitting this machine does.