So I purchased a Cat 12 Grader last year. It was made in the 40's I believe. It has a pony motor that starts the diesel. It was started for me when I purchased it and I ran it all day cutting new roads. Worked great. Then I tried to start it on my own and messed it up. It has a 6volt system. The battery was dead so I used a 12 volt to "jump" it. I had it hooked up only for 30 seconds or so while I was pushing the start button. It sounded like it was going to fire up, kept turning and turning but just didn't quite fire up. Then all the sudden nothing. I think I had the 12 volt connected too long and fried it. Is there a simple solution to replacing the starter? Can I change it over to a 12 volt starting system? Take a look at my prior thread to see my pics if you need to get a better idea of my machine. Thanks!
Cat used to offer kits for conversions to electric start. I don't know if they still do. But you can call Rust or Wagner or whatever they call themselves these days and ask. If parts doesn't offer much help, call service and they should be able to offer you the specs on the starter and maybe some other help too. Good Luck!
What kind of pony motor is it? you may have just popped a fuse in the starter switch circuit. I have used 12 volt to jump six plenty of times without any problem. Could just be the solenoid on the pony motor is not engaging.
There's a pull rope pulley but I won't go there and don't ask me how I know To change to 12V you need a good electric shop, they can change the coils in the generator and starter, you will also need a voltage regulator. Man, I'm glad those days are behind me!!
The starter doesn't care what voltage you use. What it does care about is how long you crank on it. Thirty seconds at a time is plenty. If the pony don't start you are doing something wrong or there is a problem. No gas, grounded switch or condensation in the distributor cap are some of the issues I've fought with. I'm sure many will tell you of other problems. You need a couple of minutes of cool down time between cranking each time. I've jumped started many old six volt ponys with twelve over the years.
Back in the day the company I worked for actually replaced the original generator on a few of these old machines with a cheap GM alternator, new bulbs, lights, etc.. Like John says, the starter doesn't care as long as you crank judiciously. Plan "B" in starting the old girls was another grader and a chain!
I used to run an old D6 that had a custom battery in it with four cells which used to spin it over quite well I heard.Every time I had to start it the battery was dead and I did not think it proper to jump it with 12 volts so I always had to use the pull rope. It had a brush rake on it and we seldom used it.12 volts on a 6 volt battery can create problems,both on the jumper and the jumpee. I imagine that any custom battery shop could build the battery for you and it would likely charge to 9 or 10 volts without any modifications.Again,I never saw it in action but it was there.Ron G
I dont think you done any damage to the unit. Are you jumping it from the battery or direct to the starter? If battery try the on the starter bypassing the wiring , if starter doesnt spin when hooked direct than the starter needs servicing.
Thanks for the responses! Grandpa- I believe I bypassed the battery and connected it to the starter, at least the possitive, the negative I just grounded to the metal on the grader. It wasn't turning over at all with the 6volt but when I hooked the 12 volt to the starter it starting turning over just never fired up, then it just stopped turning over. It may have made a buzzing sound after that when I hit the starter button, hard to remember as I did this back in july or so. I am trying to gather some info and better educate myself on it as I would like to have it up and running by spring as the snow melt makes the dirt easy to cut into. any websites that offer parts for these old graders? thanks again! I will try to post some pics tonight of the road I was able to cut the one day i had her working as I was quite impressed with my work having never opperated one of these ol girls before
Most any auto parts store can check the starter. There are auto rebuild business around that fix starters, generators and alternators. Good Luck!
Take the starter off and inspect the brushes, i would be one of em is stuck or hung up.Those old cat starters were tuff as nails. You can get parts for the starter at most decent auto parts dealers, if not your local cat dealer can still get your parts. Make sure the little switch for the mag is turned on when your trying to start it. Its outside by the decompression lever.:usa
first Check the electrical connections between the selonoid and the starter motor its self. Mine has a metal lug connecting the two and it will occasionally get corosion in the conection. Just loosen the nuts a bit and retighten then,,maybe a couple times just to insure good contact. If that dont fix it, try banging on the back end of the starter motor with something...if its stuck brush that will often free them enough to get it going again. I would also suggest you btpass the selonoid and hook the jumper cable direct to the starters terminal to verify its the motor and not the selonoid thats the problem. My ole 8T has been switched to 12v since i have owned it..several years, but the starter motor is still 6v and has been fine. Just as said already, dont sitr and crank and crank without cool off time. If the motor cranks but wont start, insure you still have spark to the plugs...magneto points can easily get dirt in them if its been sitting unused very much. If its got spark, then its probably got crud in the fuel tank that has shook loose on your hills and rocks and now has the outlet of the tank where the sediment bowl threads in plugged up. Clean the sediment bowl good after you remove it from the tank and poke a wire up in the tank hole to open it up and let the crud flush out. If its very bad, remove the tank and clean it well. Your 112 has the same motor and pony as my ole D4 cats do so im pretty familiar with them and their ills. Also, always kill the pomy motor by shutting off the fuel at the sed bowl. I never turn it off by the switch as they will flood over when not running and fill the crankcase with raw gas and you wont know it till its to late.
My old girl gets vapor locked in the fuel lines between the pony and the shut off valve in the cab just lossen them up a bit till you get fuel there on the carb side and presto starto. Also as said before 12 volts makes them ponys start a lot better than that 6 volt crap just don't let the starter get warmer than you can confertebly hold your hand on. Also the start button on mine is right on the bottem of the starter and some times you have to hit it with the palm of your hand pretty hard a couple of times to maker work.
There was a kit on ebay a couple days ago to convert an old Cat grader to electric start. I don't remember which model it fit, but it may still be there.
Check the mag for spark and try to keep dry i used a old mud flap.and dont forget to turn gas, there should be a fuse up under the dash
8 volt battery and such. Hello. A 4 cell lead acid battery is an 8 volt unit, sometimes referred to as high voltage 6. http://www.ehow.com/how_2240428_charge-8volt-battery.html Running the starter on 8 volts is no biggie. 12 volts is pushing it but can be done if careful. If you do convert the pony motor to 12 or 24 volts connect an alternator to the main engine. I like the GM delcotron , would prefer a self-biased unit, only one wire to connect. If you want to fix what you have you may need to replace the regulator. http://store.alternatorparts.com/delco-3.aspx Cat used the Motorola alternator and later the GM units on the alternator conversion. Let me know what you want to do as I understand Cat electrical and electronics inside out. To convert to pure electric start is expensive, as you will need to add the starter as well as large batteries. Bottom line is this, if you can get the pony engine to work, go for it.
I always start mine by pulling it with my 920 wheel loader,after i threw away the pony motor.
nmmountainman,..... All of the previous posters have given you great information about these cantackerous old girls. At least the unit is as basic as you can get. Get a test light & check for juice at the switch. With the switch in the on position check both terminals. If you have juice there, follow the wire to the fuse & check it, then check where the wire connects to the magneto. If this switch wire is dead there will be no juice to the magneto or spark to the spark plugs. When you get the starter to turning the motor check the spark plug wire for spark. Pull one of the plugs out of the motor and ground it to the motor with spark plug wire connected. You will be able to see the spark plug spark while turning the motor over. If there is no spark the mag probably has moisture or dirt in it. You can use electric parts cleaner to dry or clean it. Blow it dry with air. Be sure it's dry before you reinstall the mag cap. This is a real common problem of the old pony motor. Once you have spark to the sparkplug and the starter is cranking the next thing to check for is the gas supply. Check the tank first (I'm sorry I'm being so basic, but I'm going back to my Dad"s directions to me in 1958, amazing how the recall is so clear. He was a great teacher), Then remove the gas line at the carburator & see if you are getting gas to it. If not trace back to the blockage. the old sediment bowls were famous for plugging as they had a little metal filter that was easily plugged. Once you get gas to the carb & you can check this by removing the needle valve with the little wire through the needle. Gas will run out of the hole where you remove the needle valve. When you gas to this point, reinstall the needle valve & do a rough adjustment on the carb to get it started, then fine adjust once it's running. The main needle valve should be turned open about 1 1/2 or 2 turns open (don't tighten the needle valve too tight when closing it or you will damage it), The idle adjustment is the little screw that is through the middle of a spring. It should be turned open about 2 1/2 turns then fine tune once the pony is warm & running. Another thing to check is the air breather. These were an oil bath air cleaner. If this machine has set for a long time it might be plugged. The service on one of these filters was to seperate the bottom bowl from the filter that sets down in it, & then clean the bottom bowl with gas & rag & soak the upper filter with gas & blow dry with an air compressor. Then fill the bottom bowl with oil to the fill line or arrows. Re insert the filter element back into the bottom bowl.Be careful not to tip it on its side when reinstalling or you might dump oil into the carb throat. Like all the other advisers above stated, 12v to the 6v is not a problem as long as you don't crank too long. I would change the spark plugs before I would even start on the project. This project should be done outdoors due to the danger of the loose gas. Try not to allow the gas to leak onto the motor. If it has, wait until it's dry so you don't catch the unit on fire. Good Luck & Keep us posted as to your progress on this. C Ya, Patrol Man (Dan) Goodearth13
I have never had much luck with the 6V system on our #12. I have jumped it with 12V many a times with no ill effects. Everyone else has given good advise on what to try. I don't think you caused any irreversible damage. As for using an 8V battery, you might want to check what the alternator/generator is putting out as it may not sufficiently charge an 8V battery. And I can attest to the fact that the ponies on these can be rope started!
Running the 6 volt starter on 12v won't hurt it at all providing you give it a chance to cool between cranks. I wouldn't be surprised if the starter motor has worn to the point where the armature is dragging. Many of those old starter motors did not have bushings in the rear plate and running on the pot metal didn't work all that well.
So........ I finally got around to taking out that starter. I took my father-in-law out there to my land and he helped me pull the starter. Sure enough it was fried, melted and all. He took a look at everything and is convinced I had the wrong weight oil in the pony motor. I had diesel oil in it, 15-40 I believe? He wasn't sure but thought that it was likely too thick of oil and it gave the starter a hard time. I believe he suggested I put in 10-30wt but he felt I should call cat to make sure. Anyone know for sure what wt oil should go in that pony motor? I am planning on buying a new starter and flushing all the fluids given how long it has sat. I am pretty excited because I think with a new starter I can get the ol' girl running again! Thanks!
I wouldn't worry at all about the 15-40, especially in your climate. A modern 15-40 diesel oil is way better oil than that old pony ever expected to get. Unless it's very cold you would never detect a difference in cranking speed.
Original spec was 30wt oil same as main engine but I wouldn't worry about matching that so long as it has adequate oil level. They only hold 1-1/2 quarts so they need all of that.
If I go to a 10-30 will it hurt anything?
After you start the diesel shut the gas off the the pony and let it run out of gas and dies.This will make starting later easyer.My dad all ways done this on a D6B and it started right up.
10-30 is a little light for hot country.....good to 104 deg. F. The 15-40 is good to 122 deg. F. I use the 30wt in the Ca. climate.
So my grader is on my property, 8,000 ft in elevation in the mountains of northern NM. Temps are from 90s in the summer to -teens at the coldest. Right now its 50's-60's while Albuquerque is in the 80's. Does that change anything?
I think you're concerned about running the diesel oil in a gas unit. The 15-40 we use has the gas engine spec covered and I would think most do. As far as weight we have run 15-40 in gas trucks for many years with no problems and it does get pretty cold here at times.
So....... I finally got my starter rebuilt and reinstalled. That fixed the issue with the pony motor not turning over. Unfortunately I couldn't get the pony motor to pop or fire up. I was thinking it could be the spark plug. Any other thoughts or suggestions?
If it's turning over now with the new starter, then it has to be ignition, fuel supply, or air supply. Pull the plug and check for spark, drain fuel bowl to ensure fuel to carb, check air filter if it has one...;.
I did check the glass fuel bowl and emptied it and saw it refill so I think it is getting fuel. It has a oil bath filter, but I have never checked it. I was thinking it could be the spark plug but was too fed up to pull it. If I were to pull it what would I check for to tell it is bad?
If you have spark just put a new plug in. If it's been there a while even with no time on it it's rusted up anyway.
And there's always compression but I don't like to go there even though we were always taught to check that first when doing a tune up. Too ugly to think about.
I'm not sure if you're still fighting the pony motor or not but if you are I may be able to help. Your blade appears to be an 8T series No.12 Cat. Looks identical to the one I have and is one hell of a good machine! Lets see..... You can use 15w40 in either the diesel or pony with no ill effects. The air cleaners should be 10 weight oil which you can use hydraulic fluid as most is 10 weight oil. I jumped mine for years with the truck (12 volts) and still cranks like new. The magneto now could be causing some problems. As previously indicated check for spark. if none is found check the cap. If you see what appear to be little black cracks or lines on the back side the spark is jumping to the wrong place and causing problems. If not there check the points for gap and or wear. Both points, cap and rotor are still available but hard to find. The mag was produced by American Bosch exclusively for cat and replacement parts are rare. I just repaired mine recently so if you have any more questions just ask.