Early k161 slow crank issue. Possibly ACR

[OKcub]

Got my 1962 cub running recently but it takes a jump starter to get it cranking fast enough to start. Starts immediately with 60 extra amps runs great after starting. Does it hot or cold. Has new tested battery. Have checked positive battery cable where it goes to the back of the starter/generator and it has 12 volts when ground to the battery. Have checked battery ground cable where it goes into the back of the starter switch and it is grounding there.

Engine is difficult to turn by hand when it’s on the compression stroke. A compression test cold gave me 150 psi turning the engine by hand. So really good compression at low engine speed.


Is the ACR not supposed to be bleeding off cylinder pressure to assist starting?

I’m getting mixed signals on whether all k161’s use a compression release or a spake retarder to assist in starting. I read somewhere before 1963 Kohler used an ignition retarding mechanism to make it easier to start.

My engine does not have a removable cam gear cover to examine the cam gear.

A kohler manual I’ve found details how to adjust the older style compression release and the newer style. It says ALL Kohler series’s engines have ACR’s but I think the book is post 1963. It details that with the valve cover removed on the compression stroke turning the engine by hand you should be able to see the exhaust valve lift a little when the pistons 2/3 the up the cylinder. Mine does not do that. The next steps to diagnose your ACR are to remove the cylinder head and the oil pan which is fine but I don’t want to crack a good running engine apart to diagnose something I don’t even know is the issue.

My engine and my whole tractor are in 3-4 shades of yellow. Would not be surprised at all if the engine isn’t original or if it’s been rebuilt. If I’m NOT supposed to have a compression release type mechanism I would say I have an electrical issue. If I AM supposed to have a compression release mechanism would say it’s not working.


Does anyone have any advice from here? I’d like to figure out if my engine is SUPPOSED to have a compression release or not.

 

[mgonitzke]

As best I can tell looking at parts diagrams, the Original only had the spark advance cam.

 

[lpalma]

Got my 1962 cub running recently but it takes a jump starter to get it cranking fast enough to start. Starts immediately with 60 extra amps runs great after starting. Does it hot or cold. Has new tested battery. Have checked positive battery cable where it goes to the back of the starter/generator and it has 12 volts when ground to the battery. Have checked battery ground cable where it goes into the back of the starter switch and it is grounding there.

Positive battery cable goes to the push button switch, then to the starter generator, the ground goes from the - on the battery to the s/g mounting tab bolt, The way you write it is seems you are hooking up the battery incorrect.

 

[OKcub]

I’m typing things backward. The colors of my battery cables are switched for some reason. The battery is not hooked up backwards and apparently I need to proof read better.

I am getting good ground from the battery to the head of the lower mounting bolt for the starter generator. I am also getting 12v to the starter switch. I found an Original wiring diagram and all my other wiring matches it even to the color.

I removed the carb and it still cranks slow. So if I have no ACR and it’s still doing the slow crank without fuel it’s not the spark retard mechanism causing it to crank slow. Is there a way to test the starter/generators?

 

[kharvey]

Measure the battery voltage while cranking, I bet it's less than 12.

 

[tkhoffman]

I’m typing things backward. The colors of my battery cables are switched for some reason. The battery is not hooked up backwards and apparently I need to proof read better.

I am getting good ground from the battery to the head of the lower mounting bolt for the starter generator. I am also getting 12v to the starter switch. I found an Original wiring diagram and all my other wiring matches it even to the color.

I removed the carb and it still cranks slow. So if I have no ACR and it’s still doing the slow crank without fuel it’s not the spark retard mechanism causing it to crank slow. Is there a way to test the starter/generators?

Battery wire terminals may have been replaced. Dont worry about colors, worry about where they terminate from the battery. CUBS never had positive Ground systems, i dont think.

 

[Robert Payne]

Just replace the Starter/generator, Start from there,,, I had the same problem with my 1972 Cub 108 with the original starter,seemed to work fine with the belt off, but when the starter/generator belt was on it barely would crank the engine,,,also make shure the belt is not too tight...

 

[mgonitzke]

Is there a way to test the starter/generators?

A machine called a 'growler' is needed to check for open or shorted windings in the armature. Something a starter repair shop would have, if such a thing still exists.

I'd start by cleaning up the commutator and replacing the brushes before getting a whole new starter/generator.