HELP with my cub 127

dieselman1 · #1 12-23-2012, 11:46 AM

I just bought a cub 127 to restore and the engine will not crank over fast enough to start. I put a new battery in it and i had the starter generator checked out and its work great. So can anyone help me out please and ideas would be greatly appreciated.

OverKnight · #2 12-23-2012, 12:09 PM

I think the first thing to check are all electric connections, especially grounds. If this tractor is unrestored, you're talking about 40 year-old connections. Are the battery cables in good condition? There's often corrosion between the terminals and the wires that's not readily visible. Adding some additional ground wires between the battery and engine is a good idea, just to get it going.
Good luck!

Methos · #3 12-23-2012, 12:49 PM

I would start with grounds as well.

steve59 · #4 12-23-2012, 03:58 PM

If the connections are all OK, the next place I'd check is the Automatic Compression Release. Pop the cam gear cover off and check to make sure the spring is on the weights correctly. Take the spark plug out and turn it over by hand to and watch to see if the exhaust valve is opening slightly.

cubfixer · #5 12-23-2012, 04:56 PM

An easy way to check the compression release is to take the plug out and crank it over several turns, then put the plug back in and crank it over several turns. If they crank the same, then the compression release is working. If it is much slower with the plug in, then the compression release is probably not working.

I am thinking that a bad connection or a tired starter may be the problem.

Good luck with your cub!

darkminion_17 · #6 12-23-2012, 06:53 PM

You can also remove the breather plate and watch the exhaust valve move ever so slightly when the acr moves it,while your in there you can adjust the valves to specs.
Just my 2¢

David a Calkins · #7 12-24-2012, 04:34 PM

Diesel man 1 . i have the same problem ,with my 125 ,would not start ,i also rebuilt the hydro as well ,thought the problem was in the hydro ,so i removed the drive shaft ,and it fired right up ,so pulled the hydro down again ,every thing was fine ,reinstalled the drive shaft ,would not fire ,pulled the drive shaft again ,and pulled the spark out ,and rolled the engine over ,no problem ,but i did hear a clicking noise ,removed the cam cover ,and seen the c/r was clicking ,so tied a thread on the spring ,and removed it ,installed a new spring .with the thread on it ,sure didnt want it too fall in the pan ,removed the thread ,set the engine back down ,with every thing back together ,fired right up ,sptong was less then $2 bucks .hope this helps .David

steve59 · #8 12-24-2012, 06:24 PM

Wiring can be eliminated by measuring the DC voltage drop (power lost) from the battery (+) terminal to the starter terminal. Place a multimeter probe on the battery (+) and the other probe on the starter terminal. Crank the engine and watch the multimeter. If the meter registers more than 0.5 volts - wiring could be a contributor to your problem. Or get your jumper cables out and go directly from the starter to the battery.

dieselman1 · #9 12-27-2012, 07:25 PM

Thanks everyone i will try all of y'all suggestions and i will let you know how i make out.

Tim.E · #10 02-18-2013, 08:23 PM

Great! I am glad you got it running. I guess by now you have learned that these starter/generators just don't turn the engine as fast as one may think it should. But,when everything (carb,points,coil,plug,condensor,valves,etc.) is "right",it doesn't take much to get the engine started. It should start within a couple of revolutions.One revolution when it is warm.
Now the AQS series engine with the "starter" is a different story.