Pulling hair out, 742 issues

[redneckchevy]

Hi, I am at my wit's end and figured I would see if any one has any ideas. I have a Bobcat 742 with the 4 Cyl ford gas engine with the Zenith up draft carb. It issues started about a year ago now. It was starting to run rough, starting hard and was low on power, So I took it into a local shop and he did new cap and router, wires, I had just did the plugs not to long before so he left them. then he cleaned out the fuel tank as it was full of stuff and plugged up, cleaned the carb and put a new fuel filter and added a 2nt fuel filter right before the gas went into the carb. Ran good for a little while then started losing power and backfiring when I was using it so it went back in. He went thru the fuel system again, Rebuilt the carb this time and added a electronic fuel pump. He said it was running okay, but the carb that is on it was crap and he was trying to find a different carb we could put on it but was having no luck. I got it back home unloaded it and used it for a while and it started sputtering and backfired and died and then wouldn't restart. He said there is nothing we can do tell we get a new carb and he is having no luck. So it has been sitting all winter. It was nice out today so I put a new set of plugs in it and got it to start. I pushed some snow for about 3-5 mins with it. It was running okay, not the best. Then it started sputtering and backfired and died. Its trying to pop off, It will act like it wants to start but as soon as you stop cranking on it, it sputters out. I pulled the plugs and they were dry, didn't smell like gas and not fouled out. So far I have $600 into it and really need a skidsteer back and I am ready to pull my hair out trying to figure out when to do. Any help would be awesome. Thank you in advance!

 

[reaperman]

What you describe sounds alot the points gap is off. I know you said it recently got a tune up but you never mentioned points. If I remember the correct gap is .020 (maybe .025) do a search to verify. I had the same engine in my old machine and the points are very fussy. I was setting the gap quite a bit and always had a extra set on hand.

 

[redneckchevy]

What you describe sounds alot the points gap is off. I know you said it recently got a tune up but you never mentioned points. If I remember the correct gap is .020 (maybe .025) do a search to verify. I had the same engine in my old machine and the points are very fussy. I was setting the gap quite a bit and always had a extra set on hand.

I will check the gap in the morning and I will message the shop and see if he checked the points.

 

[craigb93]

I will check the gap in the morning and I will message the shop and see if he checked the points.

Probably need a new condenser. You can match it up at Advance Auto Parts. Fits a Volkswagen. Also can find points there but again you need the old part in hand. When you replace the points be sure to set the gap @ 0.020 and put the least bit of wheel bearing grease on the distributor lobe. Otherwise the point gap will close up in not many hours. In another thread recently I described the need to clear the carburetor main jet AND the immulsion tube holes. They are number drill sizes. Ethanol fuel corrodes these small holes and kills engine power due to the leanness of the mixture. Just carburetor cleaner won't clear the crud. -Dick (If you need more help send contact information.)

 

[redneckchevy]

Probably need a new condenser. You can match it up at Advance Auto Parts. Fits a Volkswagen. Also can find points there but again you need the old part in hand. When you replace the points be sure to set the gap @ 0.020 and put the least bit of wheel bearing grease on the distributor lobe. Otherwise the point gap will close up in not many hours. In another thread recently I described the need to clear the carburetor main jet AND the immulsion tube holes. They are number drill sizes. Ethanol fuel corrodes these small holes and kills engine power due to the leanness of the mixture. Just carburetor cleaner won't clear the crud. -Dick (If you need more help send contact information.)

Okay, So all Y'all are leaning more to spark issue then a fuel issue? I have been more focused on it being a fuel issue, If I am replacing the points and condenser should I get a new coil and that white ceramic resistor as well? We just got 7-10 inch of snow last night and 45MPH winds today so I will most likely not be able to get to the parts store today.

 

[walio123]

Okay, So all Y'all are leaning more to spark issue then a fuel issue? I have been more focused on it being a fuel issue, If I am replacing the points and condenser should I get a new coil and that white ceramic resistor as well? We just got 7-10 inch of snow last night and 45MPH winds today so I will most likely not be able to get to the parts store today.

Craigb93 is right. If you've already removed the spark plugs, put them on the wires and set them to have a ground. Let someone turn the starter, you have to have a nice, strong, blue-colored spark. You must even hear sparks. If the condenser is burnt, you will not have a spark or it will be very weak. You can clear pointers with folded in two sandpaper by puting it between contacts and rubbing a little. The other thing is to have spark plug cables exchanged. The engine will only run at 2 cylinders.

 

[redneckchevy]

Craigb93 is right. If you've already removed the spark plugs, put them on the wires and set them to have a ground. Let someone turn the starter, you have to have a nice, strong, blue-colored spark. You must even hear sparks. If the condenser is burnt, you will not have a spark or it will be very weak. You can clear pointers with folded in two sandpaper by puting it between contacts and rubbing a little. The other thing is to have spark plug cables exchanged. The engine will only run at 2 cylinders.

Okay, So I put in a new condenser, coil and resister, The points were replaced when the cap and rotor was done but when I put the bar on the engine and started turning it to check the gap the points didn't even move as it spun. So I set them to .20. It seems to have good blue spark and I can get it to start with a lot of cranking but its runs really rough for 30 sec then die's. Didn't backfire but wont run for more then prob 30 sec's and its a rough running.

 

[bobben]

Okay, So I put in a new condenser, coil and resister, The points were replaced when the cap and rotor was done but when I put the bar on the engine and started turning it to check the gap the points didn't even move as it spun. So I set them to .20. It seems to have good blue spark and I can get it to start with a lot of cranking but its runs really rough for 30 sec then die's. Didn't backfire but wont run for more then prob 30 sec's and its a rough running.

A pertronix electronic ignition system would eliminate the points and condenser they work great for around $125 bucks no setting points with better spark. I am thinking you are getting some crap out of the gas tank maybe try cleaning the carb again and try running it with a temporary tank. Maybe strap a outboard fuel tank to it to see if it runs better

 

[redneckchevy]

A pertronix electronic ignition system would eliminate the points and condenser they work great for around $125 bucks no setting points with better spark. I am thinking you are getting some crap out of the gas tank maybe try cleaning the carb again and try running it with a temporary tank. Maybe strap a outboard fuel tank to it to see if it runs better

I was looking at them, I was thinking if replacing what I just did made it run I would go that route but it still wont run after setting the points and replacing all of that. the fuel filter right before the carb is full of gas, and if I pull the line off the carb, the pump seem to push out gas good.

 

[bobben]

I was looking at them, I was thinking if replacing what I just did made it run I would go that route but it still wont run after setting the points and replacing all of that. the fuel filter right before the carb is full of gas, and if I pull the line off the carb, the pump seem to push out gas good.

the carb has some very small holes drilled in it doesn't take much to plug them up all you need is spark, compression , gas to make it run

 

[bobben]

I was looking at them, I was thinking if replacing what I just did made it run I would go that route but it still wont run after setting the points and replacing all of that. the fuel filter right before the carb is full of gas, and if I pull the line off the carb, the pump seem to push out gas good.

there are some pretty small holes drilled in the carb doesn't take much to plug them up can be a real pain with a tank that has a little contamination just because your fuel bowl is full doesn't mean its getting through the carb all you need is spark, compression, gas to make it run

 

[redneckchevy]

there are some pretty small holes drilled in the carb doesn't take much to plug them up can be a real pain with a tank that has a little contamination just because your fuel bowl is full doesn't mean its getting through the carb all you need is spark, compression, gas to make it run

It was cleaned once then still wasn't running right and had a rebuilt kit put in it and cleaned up again and still not working. also had the gas tank clean the first time and has 3 fuel filters on it now before the gas gets to the carb.

 

[walio123]

It was cleaned once then still wasn't running right and had a rebuilt kit put in it and cleaned up again and still not working. also had the gas tank clean the first time and has 3 fuel filters on it now before the gas gets to the carb.

3 filters are too big fuel barrier. Check your lift pump. Just leave 1 filter.

 

[redneckchevy]

3 filters are too big fuel barrier. Check your lift pump. Just leave 1 filter.

Lift pump has been replaced with a electric fuel pump.

 

[walio123]

Lift pump has been replaced with a electric fuel pump.

There are four reasons why what you describe may happen: 1.Ignition system is damaged or timing is wrong. Once you have a good spark and adjusted points, it only remains timing. It must be 12 degree BTC and centifugal advanse must work correctly. 2. Dirty fuel mixture - There are a lot of things to do to check : Carburetor , throttle, governor and linkage. I will only describe the basic things to look at.Distance between centers of pivot points on linkage must be 123,8 mm o( 4-7/8 inhces).Check that there is free movement on throttle plate in the caburetor when linkage is disconected..Check that choke plate works. Check that carburettor solenoid works. If the carburettor is set correctly / fuel level, correct jets/, when playing with a little throttle, it must run. The electric pump you set up must be low pressure so as not to damage the float in the carburetor and to supply a lot of fuel / I do not know the exact word in English, we say that it drives the engine. 3.Poor compresion - Measured with a tester, but there are other recesses on which you can tell if it is - if it throws out a little oil from the dipstick. 4.Water in fuel.- In your case I guess not that, You said you cleaned it all over and over again. If there are vague things ask. And never hurry to buy anything before you know it's damaged. With these things, they do not get better. You have to act methodically. And do not be angry, the nerves are a bad counselor. Sometimes it is quite difficult, especially for young people. He wants them to solve all the tasks with the computer ....

 

[redneckchevy]

There are four reasons why what you describe may happen: 1.Ignition system is damaged or timing is wrong. Once you have a good spark and adjusted points, it only remains timing. It must be 12 degree BTC and centifugal advanse must work correctly. 2. Dirty fuel mixture - There are a lot of things to do to check : Carburetor , throttle, governor and linkage. I will only describe the basic things to look at.Distance between centers of pivot points on linkage must be 123,8 mm o( 4-7/8 inhces).Check that there is free movement on throttle plate in the caburetor when linkage is disconected..Check that choke plate works. Check that carburettor solenoid works. If the carburettor is set correctly / fuel level, correct jets/, when playing with a little throttle, it must run. The electric pump you set up must be low pressure so as not to damage the float in the carburetor and to supply a lot of fuel / I do not know the exact word in English, we say that it drives the engine. 3.Poor compresion - Measured with a tester, but there are other recesses on which you can tell if it is - if it throws out a little oil from the dipstick. 4.Water in fuel.- In your case I guess not that, You said you cleaned it all over and over again. If there are vague things ask. And never hurry to buy anything before you know it's damaged. With these things, they do not get better. You have to act methodically. And do not be angry, the nerves are a bad counselor. Sometimes it is quite difficult, especially for young people. He wants them to solve all the tasks with the computer ....

Just about all of the ignition system has been replaced now (Every thing but the distributor its self) seem to have a nice blue spark. As far as timing, How do you check timing on this engine? I am more a chevy V8 guy and this engine is so jammed in there I'm not sure were to check it on this motor. I will be getting a compression tester here soon to check that. When you say carburetor solenoid, are you talking about the fuel shut off on the bottom of the carb? If so I was wondering how you go about testing that.

 

[walio123]

Just about all of the ignition system has been replaced now (Every thing but the distributor its self) seem to have a nice blue spark. As far as timing, How do you check timing on this engine? I am more a chevy V8 guy and this engine is so jammed in there I'm not sure were to check it on this motor. I will be getting a compression tester here soon to check that. When you say carburetor solenoid, are you talking about the fuel shut off on the bottom of the carb? If so I was wondering how you go about testing that.

To check timing you need to remove the belt shield.There are two marks on the crankshaft pulley. On the front cover of the engine there are notches with numbers above them 0, 4, 8, 12. You have to match them that one mark is on 12 and the other is close to 8. Remove the spark plug on cylinder number 1 / the one to the distributor /, put it on the wire and put it on a nice ground.Put the ignition switch ON. Loosen the distributor and start rotating it slowly. When you see / hear the spark, stop rotating the distributor. Tighten it. This is the procedure for the right timing. Also check that no ignition spark plug wires are exchanged. If you look at the distributor top, counterclockwise after the wire on cylinder 1, it must be wire to cylinder 2, followed bywire to cylinder 4, followed by wire to cylinder 3. The firing order of these engines is 1-2-4-3, a lot of people confuse it with the usual 1-3-4-2. As for the carburetor solenoid - yes it is. To check it, remove the wire from it , you need to remove the top part of carburetor with float. Attach a long wire to the solenoid, put the ignition key in the ON position. There should be no gasoline run. Touch the wire attached to the solenoid to the battery plus the gasoline should run. Be very cautious because gasoline has very volatile vapors and can cause a fire.

 

[walio123]

To check timing you need to remove the belt shield.There are two marks on the crankshaft pulley. On the front cover of the engine there are notches with numbers above them 0, 4, 8, 12. You have to match them that one mark is on 12 and the other is close to 8. Remove the spark plug on cylinder number 1 / the one to the distributor /, put it on the wire and put it on a nice ground.Put the ignition switch ON. Loosen the distributor and start rotating it slowly. When you see / hear the spark, stop rotating the distributor. Tighten it. This is the procedure for the right timing. Also check that no ignition spark plug wires are exchanged. If you look at the distributor top, counterclockwise after the wire on cylinder 1, it must be wire to cylinder 2, followed bywire to cylinder 4, followed by wire to cylinder 3. The firing order of these engines is 1-2-4-3, a lot of people confuse it with the usual 1-3-4-2. As for the carburetor solenoid - yes it is. To check it, remove the wire from it , you need to remove the top part of carburetor with float. Attach a long wire to the solenoid, put the ignition key in the ON position. There should be no gasoline run. Touch the wire attached to the solenoid to the battery plus the gasoline should run. Be very cautious because gasoline has very volatile vapors and can cause a fire.

I forgot to say. When you remowe the top partof the carburetor, check the fuel level on carburetor bowl. It should be 1.15".

 

[redneckchevy]

I forgot to say. When you remowe the top partof the carburetor, check the fuel level on carburetor bowl. It should be 1.15".

I haven't had time to do much to it. I did do a compressing check on it and it was reading around 120 across all 4.