743b won't start. need advice.

[idwoodhauler]

I just finished a 6 week job where we put over 100 hrs on my 743b. It was a demo job and it worked great the entire time running bucket, forks and grapple. It seemed to be starting slower and require more preheating as the job went on. I thought it was the batt. at one point but it tested ok then discovered a loose ground which seemed to fix the problem. Hauled it back 700 miles and now it won't start to get off the trailer. It kept cranking, seemed slow and labored and wouldn't start with a jump. I went and got a new batt- same thing. Now it is cranking even slower and almost sounds painful. I'm thinking it could be the starter? I tried heating the motor and jumping but the last couple cranks sounded pretty bad so I gave up and here I am. I'm pretty bad with mechanical stuff. I tried starting fluid and cleaning air filter too. Any advice is much appreciated.

 

[Tazza]

Start by grabbing the right steering lever, pull it all the way to the left and let it spring back to centre. This controls your aux hydraulics, its the most common cause of slow cranking as it loads down the hydraulic system.
How is the air filter?
Does it blow any smoke? usually white when its trying to start, with a sweet smell to it (unburnt fuel)

 

[doger5]

Check the ground voltage to see if the ground cable has internal corrision. If that ok ,check the wiring when the cab is open to the up position at the flex point of the wiring harenst mine cracked do to age and mine wouldnt start just one broken wire.

 

[idwoodhauler]

Check the ground voltage to see if the ground cable has internal corrision. If that ok ,check the wiring when the cab is open to the up position at the flex point of the wiring harenst mine cracked do to age and mine wouldnt start just one broken wire.

Tried again yesterday and it barely cranked, sounded like the motor was filled with mud. Then just clicked. I'll try testing the ground. Probably have to take it to a mechanic.

 

[Chipperhead]

Tried again yesterday and it barely cranked, sounded like the motor was filled with mud. Then just clicked. I'll try testing the ground. Probably have to take it to a mechanic.

My impression is bad connection between battery and starter. Maybe terminal crimps at either end. Did you clean the terminals when you replaced the battery?

 

[jerry]

My impression is bad connection between battery and starter. Maybe terminal crimps at either end. Did you clean the terminals when you replaced the battery?

have you checked the new battery with a load tester? I have had new batteries that were bad, its not common but it does happen.

 

[idwoodhauler]

have you checked the new battery with a load tester? I have had new batteries that were bad, its not common but it does happen.

Cleaned the terminals a bunch. Checked grounds today and they were good. Will check cables tomorrow. I have a feeling it's the starter. Thanks for the input guys.

 

[idwoodhauler]

Cleaned the terminals a bunch. Checked grounds today and they were good. Will check cables tomorrow. I have a feeling it's the starter. Thanks for the input guys.

turns out it is the starter as suspected. Tapped it while turning the key and it barely chugged. Ordered the part today.

 

[idwoodhauler]

turns out it is the starter as suspected. Tapped it while turning the key and it barely chugged. Ordered the part today.

Just an update in case this may help someone in the future. They sent the wrong starter so I had to send it back and lost a couple weeks in the process. Got the old one rebuilt for a fraction of the cost. It cranks better than it ever did before- since I got it. It still seems to take longer to fire up than it should- like 3 tries around 10 sec. each. It puts out white smoke until it gets going. Not sure what it needs but I think a tune up and fluid change might be in order.

 

[Tazza]

Just an update in case this may help someone in the future. They sent the wrong starter so I had to send it back and lost a couple weeks in the process. Got the old one rebuilt for a fraction of the cost. It cranks better than it ever did before- since I got it. It still seems to take longer to fire up than it should- like 3 tries around 10 sec. each. It puts out white smoke until it gets going. Not sure what it needs but I think a tune up and fluid change might be in order.

Glow plugs.
White smoke at startup, or attempted startup is unburnt fuel. Its not getting hot enough for the fuel to detonate. Ensure you are getting power to the glow plugs and make sure they are good. Remove them and make sure they glow red right to the tip.

 

[idwoodhauler]

Glow plugs.
White smoke at startup, or attempted startup is unburnt fuel. Its not getting hot enough for the fuel to detonate. Ensure you are getting power to the glow plugs and make sure they are good. Remove them and make sure they glow red right to the tip.

Thanks Tazza- that sounds right. How do I check the glow plugs? I'm not even sure where they are. Would I have to get replacements from bobcat?

 

[skidsteer.ca]

Thanks Tazza- that sounds right. How do I check the glow plugs? I'm not even sure where they are. Would I have to get replacements from bobcat?

Get the number off them and order new ones from you favourite sparkplug dealer.
Under $10 each. think I used sparkplugs.com Napa etcs should be able to get them.
You test by conecting to a battery and seeing how quick they get hot and how red they get.
Ken

 

[Tazza]

Get the number off them and order new ones from you favourite sparkplug dealer.
Under $10 each. think I used sparkplugs.com Napa etcs should be able to get them.
You test by conecting to a battery and seeing how quick they get hot and how red they get.
Ken

They are on the left hand side of the motor, just under the inlet manifold. They can be a pain to remove as access is tight, you may need to remove the manifold bolts to lift it up. The easiest one is the rear one. Pull it first and have a look to see if its good by connecting it to a battery and it should glow to the tip.

 

[idwoodhauler]

They are on the left hand side of the motor, just under the inlet manifold. They can be a pain to remove as access is tight, you may need to remove the manifold bolts to lift it up. The easiest one is the rear one. Pull it first and have a look to see if its good by connecting it to a battery and it should glow to the tip.

I had the glow plugs replaced about a month ago. I haven't been running it much. When I have it's still hard starting,almost like it's gelled. It sounds strained and kicks out smoke- sometimes black, sometimes white. Then it will kick over really fast and start right up. Runs like a top. I did a real dirty/dusty job with it last winter so I'm going to have it checked out and serviced. Your advice has been very helpful so far. Thank you.

 

[Jimbob]

I had the glow plugs replaced about a month ago. I haven't been running it much. When I have it's still hard starting,almost like it's gelled. It sounds strained and kicks out smoke- sometimes black, sometimes white. Then it will kick over really fast and start right up. Runs like a top. I did a real dirty/dusty job with it last winter so I'm going to have it checked out and serviced. Your advice has been very helpful so far. Thank you.

Be sure to clean/replace the aircleaner.They can clog up really quickly in dirty and dusty working conditions.The aircleaner will choke up with dust in a very short time in the conditions you described.

 

[idwoodhauler]

Be sure to clean/replace the aircleaner.They can clog up really quickly in dirty and dusty working conditions.The aircleaner will choke up with dust in a very short time in the conditions you described.

Looks like I'm back to square one on this. I brought it back to my mechanic, for a service (oil change,lube etc)-he tested it and found loose/bad connection to glow plugs and put in a little toggle switch to preheat before starting. It just wont crank hard anymore. Very hard to start, even with jumping. So I'm afraid all the cranking caused me to wear out the starter again and now need it rebuilt again. I'm thinking of having him pay or split costs since he should have taken care of the plugs connection when he did them, not to mention the first time the starter was rebuilt. Not sure if it means anything but the pos battery cable gets very hot when cranking. Gonna put a charger on it today and see if I can get it running to get to the shop (across the street). Sure runs like a top once started. Would be really nice to be able to start/use 'Bob' when I need it....the joys of a used machine..

 

[Tazza]

Looks like I'm back to square one on this. I brought it back to my mechanic, for a service (oil change,lube etc)-he tested it and found loose/bad connection to glow plugs and put in a little toggle switch to preheat before starting. It just wont crank hard anymore. Very hard to start, even with jumping. So I'm afraid all the cranking caused me to wear out the starter again and now need it rebuilt again. I'm thinking of having him pay or split costs since he should have taken care of the plugs connection when he did them, not to mention the first time the starter was rebuilt. Not sure if it means anything but the pos battery cable gets very hot when cranking. Gonna put a charger on it today and see if I can get it running to get to the shop (across the street). Sure runs like a top once started. Would be really nice to be able to start/use 'Bob' when I need it....the joys of a used machine..

If the cables get hot, i believe your problem is there. They shouldn't get hot, its possible you have a bad connection or crimp on the +ve cable.
Does the conections at the starter get hot fast too? i wonder if the main problem is the connections in the solenoid on the starter are dirty. When the starter was rebuilt, did they put a new solenoid on it? if not, its possible that's your problem of a lack of power.
Any point that is generating heat is a point where power from the battery is being lost. Hot starter cables means you have higher resistance and you will not be getting full power to the starter.

 

[money]

everytime a skid steer wont start for me all i do is check all of the saftey features and make sure they are not buggy because they will not start if it is not SAFE!!! haha

 

[idwoodhauler]

everytime a skid steer wont start for me all i do is check all of the saftey features and make sure they are not buggy because they will not start if it is not SAFE!!! haha

The machine refused to start in the middle of a project over week ago. I think the starter burned up because it was so hot and doing what it did before the first rebuild. The mech. said he'd get it rebuilt for me again. So he did that and put it in and cranked real fast like it should but just wouldn't start...so close but just wouldn't fire up. Then it did with a squirt of ether. It idled about 30 min. then I shut it off and restarted it twice instantly, without preheat-even though it was warm out. Before, even when warm from running it still required some preheat... I'm horrible with motors so I told him to do/check whatever could be possible problems. The batt was fine & he said he'd replace the fuel filter monday. I found him out there cussing the design of the filter changing it out...which kind of gets me worried since he's very soft-spoken. When I got back and looked at it there was fuel leaking out all over and that glass piece had broken. He hadn't realized it but had tried to start it and not realized whether pressure broke it or what-and didn't bother to look I guess. So 3 days to get that part..after market metal...he's paying for it of course. He felt really bad about all this and is getting frustrated too on why its acting like this. So this is causing me a lot of aggravation because it'll be down over 2 weeks and is costing me $!! I just felt like venting so thanks for listening. It's been such a good machine but I really hope this solves why it's so hard starting.