1987 310-8 key switch to plug match problem

[Armadillo👍 6]

With the 301991 switch installed the engine turns over but won’t start. The spark plug has a good strong spark. No start using starting fluid either. 
Since the push to start button by passes all the wiring I’m going to remove the 301991 start switch and hook the push to start button back like it was and see if the engine starts.

There seems to be good compression but I’m going to get a compression tester and test compression just in case.

[953 nut 67,900]

Compression tests on a Kohler with compression release can be a bit hard to go by. The cam shaft has a feature that releases some of the compression until the engine is turning over a couple hundred rpms to make it easier to start.

If it ran good before it shouldn't be a compression problem unless it was opened up or the valves adjusted. Even though the engine has good spark I would start with a new spark plug.        

[Armadillo👍 6]

I had forgot about compression release. It did run before. It has a new spark plug. Thank you.

Edited August 11 by Armadillo👍

[pfrederi 20,964]

I would put back the old plug that was in her when she last ran...Wouldn't be the first time a new electrical thing didn't work....especially if it is a Champion they fail to fire under compression

[sqrlgtr 3,510]

[Armadillo👍 6]

Finally got back to work on the Wheelhorse. Pulled the key start. Turned engine over with wire connection from battery to solenoid. Engine started. Yay!

Rechecked all the wiring and realized the ground wire attached to the 103991 switch wasn’t grounded.

Reading the diagram for 1987 301 models the ground wire from the key switch goes to the seat switch. The seat switch, when the seat is sat in, seems to not be grounded but the diagram shows another ground between the key switch and the seat switch. If that is true, is the ground for the seat switch controlled by the key switch??

Second question. It would be useful if the battery was charged when the engine is running. The diagram shows a ground and 1 hot wire for the battery. Does the battery charging circuit (if there is one) go through the key switch?

Thank you diagram reading gurus for your answers.

 

[gwest_ca-(File Mod) 12,404]

One side of the seat switch is grounded. With operator in the seat and the pto ON the switch is open so the magneto wire is not grounded and the engine runs. Operator leaves the seat the switch grounds the magneto and engine stops.

If the pto is OFF the magneto ground can not get to the seat switch so engine will run operator or no operator in seat.

[953 nut 67,900]

Your wiring on the 310-8 was designed for a battery powered ignition system and you have installed a Magnum in place of the old engine, is this correct?

The safety switch wiring for a battery powered system is different than that of a magneto system. With the battery powered system the safety switches remove voltage to the coil if you leave the seat with the PTO on. With a magneto system the ignition becomes grounded if the driver gets off the seat with the PTO on.

If you want to have your safety switches to work as they should the ignition switch socket needs to be changed back to the way it came from the factory, a 103990 switch and a kill relay installed or completely rewire the safety switches. Going back to the 103990 and kill relay would be much easier.

 

[Armadillo👍 6]

It’s clear that diagram logic is more difficult than identifying wires, tracing them out and testing for continuity.

If I understand correctly the diagram just shows the seat and key switch just have a common ground.

The diagram answered my second question because with the key switch in the run position has the battery terminal and rectifier terminal connected. I may be slow but I get there.

Thank ya’ll again for all the help!