1992 743B cold starting PAIN

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RobPg1967

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Hey guys - my 743B needs a shot of starting fluid every morning - once she's warmed up starts just fine. I hold the key counterclockwise ( ignition) for 30 seconds for the glow plugs to kick in but doesnt seem to help. If I need new glow plugs - I really could use a crash course in changing them . There always seems to be a trick or two when it comes to stuff like this and since I never changed these plugs I figure asking you old pro's will definately help me out. Thanks
 

Tazza

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There is no easy way i'm afraid.
You will need a 12mm deep socket on a 1/4” drive ratchet set.
The hardest part is getting the socket between the inlet manifold and the outside of the plug. At the injector pump you will need to remove a tube line or 2 to gain access. Just take your time and you will be fine. Your best bet is to take the plug from number 4 out first as its the easiest and get it matched. From bobcat its far too expensive. I paid less than $10 AUD each for mine.
Before you start pulling plugs, check they are getting power, it could be as simple as a dead relay.
 

Fishfiles

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I will usually check for voltage at the glow plug with a test light on the bar that runs from one to another and feel the head of the glow plug with a wet finger after holding the glow plug on , and you can pretty much tell if they are getting hot or not ----but I am affraid that you hard starting is most probally a compression problem , especially since it has become a starting fluid addict ------ it's a good time to check the compression when the glow plugs are out , if you don't have the adaptor to check the compression thru the glow plug holes and you or some one you know welds you can take the old glow plug and cut the top off with a hack saw or grinder and use a punch to punch the electrode rod out the center , leaves a perfect hole right thru the threaded tube , then weld ( preferabally Tig weld or acctylene braze ) a fitting which will connect to a compression tester to the glow plug and you have a adaptor , don't have the book in front of me but seem to remember the compression should be well over 400psi , something like 475 and no more than 10% difference between any cylinders , under 400 and it will probally be hard starting good luck
 

Tazza

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I will usually check for voltage at the glow plug with a test light on the bar that runs from one to another and feel the head of the glow plug with a wet finger after holding the glow plug on , and you can pretty much tell if they are getting hot or not ----but I am affraid that you hard starting is most probally a compression problem , especially since it has become a starting fluid addict ------ it's a good time to check the compression when the glow plugs are out , if you don't have the adaptor to check the compression thru the glow plug holes and you or some one you know welds you can take the old glow plug and cut the top off with a hack saw or grinder and use a punch to punch the electrode rod out the center , leaves a perfect hole right thru the threaded tube , then weld ( preferabally Tig weld or acctylene braze ) a fitting which will connect to a compression tester to the glow plug and you have a adaptor , don't have the book in front of me but seem to remember the compression should be well over 400psi , something like 475 and no more than 10% difference between any cylinders , under 400 and it will probally be hard starting good luck
They are rated at about 475PSI new but i was told as low as 300 was about as low as it should be before starting is very hard and loss of power is an issue. One way to check for wear is to see how much blow-by you have. If there is a lot its probably a compression issue, if there isn't much its probably plugs or a relay.
After a re-build mine was just over the 400 PSI mark, it still starts pretty easy with a 10-20 second glow. It blows a bit of white smoke at start up though. I think the piston to head height isn't quite rite.
When its warm it runs well you said, no smoke? as it could be an injector issue if it blows excessive smoke.
From what i was told about starting fluid is the modern stuff has lubricants in it unlike the old stuff that would damage engines from lack of lubrication.
Its not a bad idea to check compression if you have the tools.
As for glow plugs, its rare for them to burn out but it does happen. I had a set that when you hook them up to a battery they would only glow at the base of the thread, they had burnt down to a point at the end. You need the plug to glow from the tip to the base or it simply will not do the job. Remove the plugs and use a test cable and a battery and see if they glow correctly (watch your fingers, they get hot FAST). If they glow correctly throw them back in, the new ones won't work any better.
Let us know how you go.
 

RobPg1967

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They are rated at about 475PSI new but i was told as low as 300 was about as low as it should be before starting is very hard and loss of power is an issue. One way to check for wear is to see how much blow-by you have. If there is a lot its probably a compression issue, if there isn't much its probably plugs or a relay.
After a re-build mine was just over the 400 PSI mark, it still starts pretty easy with a 10-20 second glow. It blows a bit of white smoke at start up though. I think the piston to head height isn't quite rite.
When its warm it runs well you said, no smoke? as it could be an injector issue if it blows excessive smoke.
From what i was told about starting fluid is the modern stuff has lubricants in it unlike the old stuff that would damage engines from lack of lubrication.
Its not a bad idea to check compression if you have the tools.
As for glow plugs, its rare for them to burn out but it does happen. I had a set that when you hook them up to a battery they would only glow at the base of the thread, they had burnt down to a point at the end. You need the plug to glow from the tip to the base or it simply will not do the job. Remove the plugs and use a test cable and a battery and see if they glow correctly (watch your fingers, they get hot FAST). If they glow correctly throw them back in, the new ones won't work any better.
Let us know how you go.
Correct - Once it is started in the morning and warms up to operating temp - she starts right up all day long - unless its cold out then another small squirt to get her going. Im also having a hydr. leak underneath between the two tires on the hydraulic tank fill side ( I was gonna say drivers side hahaha ) This leak drips while engines running only - Im gonna lift up the cab and take a look sometime soon - I hope it isnt some sort of gearcase problem - replacing lines I can do . As always - throw your 2 cents in its always helpful. I'll keep ya posted.
 

skidsteer.ca

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Correct - Once it is started in the morning and warms up to operating temp - she starts right up all day long - unless its cold out then another small squirt to get her going. Im also having a hydr. leak underneath between the two tires on the hydraulic tank fill side ( I was gonna say drivers side hahaha ) This leak drips while engines running only - Im gonna lift up the cab and take a look sometime soon - I hope it isnt some sort of gearcase problem - replacing lines I can do . As always - throw your 2 cents in its always helpful. I'll keep ya posted.
This is going to sound dumb but are you sure turning the key left is to power the glow plugs.
On the slightly newer 93 94 machines that function is to relieve the hyd pressure at the quick couplers. Glow plugs were on a separate rocker switch.
However I could certainly be wrong about yours. Take your test lite to the bar between the glow plugs and see if it powers up.
Regards
Ken
 

Tazza

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Correct - Once it is started in the morning and warms up to operating temp - she starts right up all day long - unless its cold out then another small squirt to get her going. Im also having a hydr. leak underneath between the two tires on the hydraulic tank fill side ( I was gonna say drivers side hahaha ) This leak drips while engines running only - Im gonna lift up the cab and take a look sometime soon - I hope it isnt some sort of gearcase problem - replacing lines I can do . As always - throw your 2 cents in its always helpful. I'll keep ya posted.
The leak could be anything. It could be the shaft seal on the hydrostatic pump, a tube line behind the engine could have rubbed through (not un-common). I would seriously doubt it would be leaking from your gearbox. Once sealed thses really should never leak as there is no movement that could break the seal.
You may want to check chain case oil level by parking on level ground and remove the plug at the front, the oil should just trickle out or you should be able to feel it with a finger.
From what you describe about starting i really do believe you have a glow plug problem. As Ken said, check the glow plug rail for power when you hit glow. If its got power, i'd pull the plugs and change them, or at least check them with a battery and heavy cable, they should glow red the full length of the tip.
 

RobPg1967

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The leak could be anything. It could be the shaft seal on the hydrostatic pump, a tube line behind the engine could have rubbed through (not un-common). I would seriously doubt it would be leaking from your gearbox. Once sealed thses really should never leak as there is no movement that could break the seal.
You may want to check chain case oil level by parking on level ground and remove the plug at the front, the oil should just trickle out or you should be able to feel it with a finger.
From what you describe about starting i really do believe you have a glow plug problem. As Ken said, check the glow plug rail for power when you hit glow. If its got power, i'd pull the plugs and change them, or at least check them with a battery and heavy cable, they should glow red the full length of the tip.
ok ... while we're at it --- heres another Q . When the hydraulic tank is full - how far is the oil level below the cap ? I didnt see any fluid in my clear , clean hydr.indicator window , So I added some fluid and stopped about 6 inches down from top ....still no fluid in indicator window. Oh yeah - and Id really like to learn the " flipping over plates " thing to reduce the forward crawl I got .
 

Tazza

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ok ... while we're at it --- heres another Q . When the hydraulic tank is full - how far is the oil level below the cap ? I didnt see any fluid in my clear , clean hydr.indicator window , So I added some fluid and stopped about 6 inches down from top ....still no fluid in indicator window. Oh yeah - and Id really like to learn the " flipping over plates " thing to reduce the forward crawl I got .
If i remember, i will take some pictures of the steering lever stops and the procedure to set them. I'm not too sure how far from the top the oil should be from the sight window, but oil should be seen at mid level of the glass. Just use a ruler or tape measure and you can work out how much more oil you need to add.
 

RobPg1967

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If i remember, i will take some pictures of the steering lever stops and the procedure to set them. I'm not too sure how far from the top the oil should be from the sight window, but oil should be seen at mid level of the glass. Just use a ruler or tape measure and you can work out how much more oil you need to add.
Thanks
 

Tazza

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Simply put, block the machine so the wheels can turn freely and lift the cab
Remove the steering linkages at the levers and the pintle arms on the hydrostatic pump. Remove the 4 bolts holding the stops to the big plate on the side of the pump, you will see a spring that puts pressure on this. Rotate the stops 180 degrees and put them back on, don't tighten them up. Start the machine and working from the back hold the stop against the pintle arm when the wheels do not move tighten the bolts up. Move it back and forth a few times and let it return to centre. If the wheels don't move its correct, if they move re-do the setup. With the back done, do the same to the front.
Its easy to explain, but it does take a bit of time to do.
To do the job rite, you should replace the pucks on the pintle arm, but the bolts are a pain to get to.
Make sure the back of the stops are not worn, they may hev been flipped already. You don't REALLY have to turn them over to get centre, you can still do it with worn bits, just do the steps i mentioned earlier. Make sure you start at the back! it will not work if you start at the front.
If anything isn't clear just let me know and i'll try to explain it better.
 

Tazza

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Simply put, block the machine so the wheels can turn freely and lift the cab
Remove the steering linkages at the levers and the pintle arms on the hydrostatic pump. Remove the 4 bolts holding the stops to the big plate on the side of the pump, you will see a spring that puts pressure on this. Rotate the stops 180 degrees and put them back on, don't tighten them up. Start the machine and working from the back hold the stop against the pintle arm when the wheels do not move tighten the bolts up. Move it back and forth a few times and let it return to centre. If the wheels don't move its correct, if they move re-do the setup. With the back done, do the same to the front.
Its easy to explain, but it does take a bit of time to do.
To do the job rite, you should replace the pucks on the pintle arm, but the bolts are a pain to get to.
Make sure the back of the stops are not worn, they may hev been flipped already. You don't REALLY have to turn them over to get centre, you can still do it with worn bits, just do the steps i mentioned earlier. Make sure you start at the back! it will not work if you start at the front.
If anything isn't clear just let me know and i'll try to explain it better.
Check out: http://users.tpg.com.au/tazza_/bobcat/Steering Adjustment.jpg
Thats out of the manual for adjustment.
 

RobPg1967

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THANKS TAZZA - Cant wait to fix this !! I'll post when Im done.
HEY - Tazz , Thanks for the instructions - I was able to decrease the creep quite a bit . very difficult to tighten the plate bolts without moving it out of adjustment. The side that used to creep ( back plate ) doesnt anymore. The side that didnt creep ( front plate ) - does now Its very minimal and just a tap on the lever and it stops ... for a little while. ------------------------------------------------------------------ NEXT - GLOW PLUG REPLACEMENT. Feel free to send along another detailed step by step FACT SHEET on this .
 

Tazza

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HEY - Tazz , Thanks for the instructions - I was able to decrease the creep quite a bit . very difficult to tighten the plate bolts without moving it out of adjustment. The side that used to creep ( back plate ) doesnt anymore. The side that didnt creep ( front plate ) - does now Its very minimal and just a tap on the lever and it stops ... for a little while. ------------------------------------------------------------------ NEXT - GLOW PLUG REPLACEMENT. Feel free to send along another detailed step by step FACT SHEET on this .
Excellent, some time you need to repeat the process to get it rite.
As for glow plugs, just a deep 12 mm 1/4“socket will do the job. You may need to remove the inlet manifold to gain access. They aren't easy to get access to but you only need to do it once.
I'd start by removing the easy one, on number 4, at the rear of the engine.
Hook it up to a battery and see if it glows correctly, if so i'd suspect they are ok.
You have checked for 12V at the glow plugs?
 

George

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As several people have mentioned in this thread you have to check the voltage getting to the glow plug.I have replaced several solinoids for the glow plugs, they just go bad and dont let the full voltage through,the test light will still light but not enough juice.Just replace the solinoid any way, it's cheep and may cure your problem.How many hours are on your machine, I had over 15000hrs on mine and I never had to use starting fluid[what we call diesel cocaine].
 

RobPg1967

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As several people have mentioned in this thread you have to check the voltage getting to the glow plug.I have replaced several solinoids for the glow plugs, they just go bad and dont let the full voltage through,the test light will still light but not enough juice.Just replace the solinoid any way, it's cheep and may cure your problem.How many hours are on your machine, I had over 15000hrs on mine and I never had to use starting fluid[what we call diesel cocaine].
Hey guys - Bobcat ran like a champ for me all summer - started ok in the mornings also because it wasnt cold out. Ive got 2000 hrs on this 743. Turning the ignition key to the left for 30 seconds actually helps start on a cold morning ... but not as good as it should. Where is this solenoid that I need to test ? Can I get it somewhere other than the dealer ?
 

Tazza

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Hey guys - Bobcat ran like a champ for me all summer - started ok in the mornings also because it wasnt cold out. Ive got 2000 hrs on this 743. Turning the ignition key to the left for 30 seconds actually helps start on a cold morning ... but not as good as it should. Where is this solenoid that I need to test ? Can I get it somewhere other than the dealer ?
Get someone else to sit in the cab and turn the key to the left. Use a test light between ground and the power rail that connects all 4 glow plugs together. If you have power, it may be worth replacing the plugs or at the very least test them. They should glow from the tip back to the body.
If there is no power, follow the cable to the glow plugs back to the solenoids just under the air cleaner. One is for the starter motor the other is the glow plugs.
 

trg753

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RobPG1967, I have a 753 Bobcat with over 4200 hrs. on it. Mine was starting a little hard and I checked the glow plugs and they seemed Ok. The next step I took was to remove the injectors and had them rebuilt. They were extremely worn and it seemed to make a big difference in starting and the way the engine runs. It might be work a look at the injectors. They are not that hard to remove and get rebuilt. Good luck, Tom
 
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