generator gets hot

Mon May 13, 2013 6:17 pm

have 154, 125psi compression,new wiring harness,volt gauge,ign switch,rebuilt gen then replaced with new one and regulator,same problem.owned 17 yrs use to turn over and crank fine,now cranks when cold then gen gets hot, sometimes coil too.once hot it cuts off, let it cool cranks again.what's causing gen to get hot??? also batt is new,when hot wont even jump,it turns so slow,but let it cool down cranks with it's own batt. then runs fine 20-30 minutes, then starts to spudder and,about to pull the trigger!

Re: generator gets hot

Mon May 13, 2013 8:56 pm

Thoughts: Engine running hot.

Flush engine block and radiator, making sure all crud removed from around and behind cylinders.

Engine recently rebuilt, bearings and or piston rings to tight. Mistake in electrical wiring. Lean carburetor and faulty ignition timing.

Re: generator gets hot

Tue May 14, 2013 5:37 pm

Hey Eugene,
Thanks for the tips,today I reflushed tractor and ran for 45 min.Nothing came out water was clean.reset timing with light to 10 degrees.took reading with heat gun when running-
block 125
head 220
coil 135
gen 98
rad 100,top and bottom.
tried to adjust carb screw doesn't effect much in or out runs fine.let mower sit for 30 min,tried to start,same thing slow turn won't crank until completely cooled off.anybody see anything in these readings that might help indicate where I should start to cure this problem,I'm all ears

Re: generator gets hot

Tue May 14, 2013 7:25 pm

Perplexed and interesting.

Couple thoughts. Get tractor warmed up again and in no start situation. Loosen generator/starter belt and turn S/G by hand. Then turn the fan by hand - looking for easy movement in both the S/G and fan.

Also try the voltage drop test while starting engine with engine cold and with engine fully warmed up.

Re: generator gets hot

Wed May 15, 2013 5:39 am

Did you have this problem before putting on the new stuff? Sounds like something getting hot, breaking down and causing a short somewhere.

Re: generator gets hot

Wed May 15, 2013 6:53 am

Yeah,randall that's whats lead to.all the replacements plus age.ok eugene that sounds like a plan to keep.narrowing down problem, cub.sat for.9.yrs amd.thought was a.gonner pulled.out.jb.blasted cyclinders got it.turnimg.over and cranking has maybe 10.hrs running.since.runs.fine but did.sit for yrs.i'll post.the outcome.later

Re: generator gets hot

Wed May 15, 2013 7:28 am

Oil pressure is?

Re: generator gets hot

Wed May 15, 2013 8:47 am

Check fuel flow to the carb I had the same problem with my 154. It had junk in the tank that would plug the out let in the tank then the engine would over heat in about 15-20 minutes and die would not restart till cool the g/s would not turn the engine over when hot.

Re: generator gets hot

Wed May 15, 2013 6:38 pm

Maybe I'm reading his post differently, but it sounds to me like this is an electrical or generator problem, not a problem mechanically with the engine. He says that the starter/generator gets hot, along with the coil. When the coil gets hot, the tractor dies and will not start or crank. This could be a couple of problems, but I would not be surprised to find that the coil is bad, or is not the correct coil. If the coil is not correct, or failing, and gets hot, then the oil breaks down and it will not produce spark as it should. Also, the starter/generator getting hot is not unusual, but if it's excessively hot, it could be a sign that the voltage regulator is not working right, placing undue stress on the starter/generator, and/or the starter/generator could be due for a rebuild.


Re: generator gets hot

Thu May 16, 2013 6:13 am

Temperature readings appear not to be excessive, actually pretty normal.

Next no start situation, tractor in 3rd gear, ignition off, try to roll tractor forward or backward by hand. Trying to eliminate mechanical problems.

Could be an electrical problem or problems. The ignition system is separate from the engine start system with the exception of when the ignition switch is in the start mode. The connection between the start and run systems is at the ignition switch.

The only item that hasn't been replaced is the solenoid. Usually a solenoid either works or they don't. Next no start situation, jump directly from tractor battery to the starter/generator. This will by pass the entire electrical system.

No start situation. Check for spark from coil to ground. Check for voltage at terminal on side of distributor.

Re: generator gets hot

Thu May 16, 2013 4:37 pm

Happened to me today. Mowed for an hour or so. Shut off tractor to open gate. Tractor no start. Starter/generator very sluggish cranking over engine. Then remembered previous owner said tractor was hard to start when warm. Tractor on slight slope, pushed on rear tire enough to get tractor rolling. 3rd gear, tractor rolling, turned on ignition, tractor runs.

Finished mowing, drove to shop. Shut off engine, tried to start engine, no start. Removed hood.

Battery voltage drop test - excellent battery condition. Voltage check while cranking engine at s/g and coil, voltage appeared good but could not get a constant reading. $1.99 digital multimeter. Will take the expensive multimeter to shop next time.

Guessing 15 to 20 minutes later, S/G turning over like a champ and engine starts.

More tests coming.

Re: generator gets hot

Sun May 19, 2013 3:02 pm

Some electrical tests conducted on a numbered Cub low-boy hard start problem when hot. John Puckett and I made some voltage and amperage tests to my 154's electrical system.

Charging voltage at battery 13.2 volts.

S/G output, about 1/2 volt, voltage drop, consumed by voltage regulator.

Amperage reading taken at battery. 12.? amps charging at medium to high engine rpms -- amp gauge showing charge. Negative 11.? amp (discharge) when engine dropped to low idle - amp gauge shows similar discharge.

Further tests:

Disconnected battery cable from solenoid to S/G at the S/G. Ignition off. Found .04 volts on cable end. After several engine starts and stops, found zero volts on cable end. Indicating that periodically the solenoid is not fully opening/disconnecting battery from S/G.

Battery cable disconnected at S/G, high amperage drain from battery still persisted at low engine idle. One check, slowly closed throttle from high to low idle, amp drain did not appear on amp gauge. Couple more tries at shutting down the throttle fast and slow disclosed the same results. Fast throttle closure, high amp drain from battery. Slow throttle closure and amp gauge indicated either zero amp drain or just enough of a drain to indicate ignition system operation.

Current conclusions:

Solenoid to be replaced this fall/winter.

Voltage regulator cutout not dropping out/disconnecting when it should. Could be wrong voltage regulator.