no spark on 982 Onan

[karamia]

Hello all. I have a CC 982 w/front and rear pto.
CC SER NO xxxxxxxU722459
MOD NO 143984399
ENGINE MOD NO B48G-GA19.9/3707B ONAN

Last year it was running fine except for the float needle sticking and flooding out the crankcase. It sat inside all winter.
I changed oil and filter and cleaned the carb. Would not start.
Checked and had good fuel , no spark. Condenser,points and plugs were new last year.
Steps I have taken so far:
1)checked coil ohms readings = fell within specs.
coil is original w/216 hrs on it

2)installed Kirk's PointSaver as per directions = no spark.

3)checked voltage @ + term on coil w/key in "run" = 12.67v
4)checked voltage @ + term on coil w/Key in "start" = 4.8v to 5.8v

Kirks instructions suggest a faulty coil if voltage less than 12v

5)replaced coil w/new Onan dual coil= no spark.
re checked voltage @ + term on coil w/key in "run" = 12.67v
re checked voltage @ + term on coil w/Key in "start" = 9.0v to 9.8v
note: new coil has standard automotive spark plug cable receptacles; therefore had to get new cables.
The new cables are standard non-metalic conductors. COULD THIS BE AN ISSUE?

6) checked ALL switches for function and possible grounding and cleaned all terminals.
One issue found @ key switch. The terminal holder was broken and some terminals had been arcing enough to burn and melt the holder slightly. Removed holder and insulated each terminal separately w/heatshrink.
NO SPARK.
re checked voltage @ + term on coil w/key in "run" = 12.86v
re checked voltage @ + term on coil w/Key in "start" = 9.5v

7)By passed the front and rear PTO switches and the relay. Disconnected the lights and hour meter.
result: (copy and paste here)
re checked voltage @ + term on coil w/key in "run" = 12.86v
re checked voltage @ + term on coil w/Key in "start" = 9.5v
Did see one (1) small spark in spark tester. Once.

Any thoughts, ideas and pity much appreciated.

Kerry.

[toyman]

You said you checked ALL switches, did you check the brake safety switch located under the driveshaft cover?

[karamia]

Originally Posted by toyman

You said you checked ALL switches, did you check the brake safety switch located under the driveshaft cover?

If you mean the "foot actuated switch" as per the "982 Cub Cadet" wiring schematic, w/ front & rear PTO (http://www.onlycubcadets.net/forum/s...ead.php?t=21); then yes I did.
I am currently running a wire from the "I" terminal of the ignition switch to the wire that went to the foot switch (goes directly to solenoid);
thereby bypassing all switches except the ignition and the seat switch, which tested as OK. I will bypass it as well to be sure.

[save_old_iron]

Kerry,

when you are taking the voltage measurements,

where do you have the ground lead for the voltmeter ?

From what you have written, my guess is there is (significant) additional resistance in the start wiring to the coil that does not exist in the run circuit wiring to the coil. The resistance of the ignition switch contacts can be measured or you can measure the voltage drop across the B to S terminals to see if that's where the extra 3 volts is being dropped while you perform your spark tests.

Another thought. Instead of measuring the coil voltage during the start test, perform your start test but measure the battery voltage directly across the battery terminals. Maybe you have a sulphated battery that drops voltage during the start testing.

Is the engine cranking over when you are measuring the 9 volts at the coil ?

p.s I seriously doubt the "standard non-metalic conductors" are the issue here with voltage drop to the coil. But that said, to check if they have any influence on what you are doing, lift the leads out of the coil and try the voltage measurements again.

[R Bedell]

You have to have a minimum of 12VDC at the Ignition Coil Input. Anything less than that may result in a weak or no spark situation.

The Plug Wires need to be a metal core cable.

[save_old_iron]

I looked further at the Onan manual and it shows a 2nd circuit from the ignition switch to the coil. The schematic shows it as a dotted line. Power leaves the I terminal of the switch - goes thru the 15 amp fuse (look for possible corroded fuse holder contacts) and then heads to the front clutch switch ( possible corroded contacts or resistance in switch) and then to wiring on the relay (corroded terminals and wiring) and then to the ignition coil. Looks like the ignition kill when the clutch is engaged and the operator leaves the seat.

??? Running a wire from the I terminal of the ign switch to the foot switch - wouldn't that just effect the starting circuit ? not the ignition circuit?

Interesting problem.

[R Bedell]

Additional thought......

I had a bad starter on my 1450 once where it dragged down the battery voltage when starting. At static, I had 13.5VDC, but while cranking, it dropped to 8.5V. This maybe an area you want to check.

Lastly, the battery itself maybe weak and has no reserve capacity.

Bottom line, you have to have 12V at the ignition coil when cranking over.

[105_Tom]

Has the tractor run at all after you found the crankcase full of fuel and drained it out? Only other thing I can think of is if the Onan has low-oil shutdown and somehow the fuel would have caused the oil pressure switch to go bad and ground out the ignition circuit. Otherwise, just check grounds, grounds, grounds - the root of soo many electrical issues! My sympathies to you for having to buy that Onan coil only to find out that now you have a non-returnable spare