Better Starter

[AKincer 6]

Kohler 341S 16HP

spec 71381

 

 

My starter just doesn't have enough torque and it often hangs on the compression stroke.  I've checked wiring and grounding and all is good.  If the battery is 100% charged, and it's not too cold, and I hold my mouth just right, I can usually get it to start, but I want to make this more reliable.

 

 

I understand that it originally came with a 13 tooth pinion, but that there is a 10 tooth version that has more torque.

 

 

Pats's Small Engines has 3 versions that are reasonably priced that look like the correct replacement for my engine.

 

MES5761N

AHSAB0043

PSEP5761N

 

Anyone with experience in converting to the 10 tooth for the big Kohlers?  Am I on the right track to make this easier starting?  Any suggestions on other alternatives or sources for a new starter?

 

Thanks in advance!

 

 

 

[Coadster32 793]

I had a block techumseh starter that was older, and it suffered trying to turn over. I replaced it with a Pat's new starter, and it cranked like no tomorrow.

[gwest_ca-(File Mod) 10,495]

Have you checked the valve clearances? If not within spec the ACR (automatic compression release) won't work. If off far enough you may have to repeat the process as the valves start to run cleaner.

 

Garry

[AKincer 6]

I did check valve clearances, but forgot to mention that.  They were spot on in the middle of the spec.

[bmsgaffer 2,043]

It sounds like the starter just may be tired. I personally don't think that the two tooth difference will make that big of a deal in our climate. It may give a little more umph per battery size for starting in really cold weather.

 

Your starter should be able to turn over that engine pretty quick.

 

This is all assuming you have:

1. Big enough battery
2. Correct size wiring
3. Good positive AND ground connections
4. Solenoid in good condition

 

If all those are good and it still is starting slow I would just replace it with the OEM style one.

Edited May 7, 2015 by bmsgaffer

[AKincer 6]

bmsgaffer,

 

You noted that the solenoid needs to be in good condition.  I know that it works because the starter engages.  I just assumed that it either works or it doesn't.  Is there some other analysis or trouble shooting that I could do on the solenoid to ensure that it is working as it should?

[bmsgaffer 2,043]

The contacts internally can wear out, but its a hard thing to test.

 

If you have a multimeter, you can check the resistance between the two big lugs when trying to start the engine (with the big wires disconnected). It should be VERY low, almost too low to read on the meter. That's not guaranteed either because the high current of the starter can cause some problems not necessarily measured.

 

The most fool-proof way of testing is to swap in a known-good solenoid, but if you dont have a spare around then it can be a more expensive way to test.

 

If i didn't have my testing equipment, I would probably start with the solenoid because if I have to get a new starter I would want a new solenoid for best performance anyways. But that's just me!

[AKincer 6]

That makes sense.  I do have a meter and may be able to come up with a spare solenoid.  Thanks for the suggestions.

[JPWH 5,308]

You may also want to check for worn bushing. I was having the same problem then one day the starter hung up on the flywheel. I replaced the bushings and brushes gave it a good cleaning now it works like New.

[oldredrider 2,547]

Hank01 is on point. Pull the starter off the engine and check for side to side play on the gear side. Any slop indicates a worn bushing and will bind the starter. Bushings are available on Ebay.

A good cleaning will do wonders for the efficiency of the starter.

[Save Old Iron 1,563]

  I just assumed that it either works or it doesn't.  Is there some other analysis or trouble shooting that I could do on the solenoid to ensure that it is working as it should?

 

Issues with a starter solenoid can arise when the internals of the solenoid become pitted and vaporized from repeated high current arcing.

 

This is a very easy condition to check by measuring voltage drop across the solenoid terminals.

 

Set your meter on low volts scale (2 volt or 20 volt scale).

 

Connect one lead of the meter to each of the large terminals on the solenoid. Crank the engine with the spark plug temporarily disconnected. Note the voltage reading on the voltmeter. Whatever voltage you see on the meter is indicative of a power loss in the solenoid - power that should be going to the starter but is being dissipated as heat in the solenoid. Typical voltage drop in a solenoid should be much less the 0.5 volts (half a volt).

If you see one or two volts dropped across the solenoid, a replacement is needed.

Edited May 8, 2015 by Save Old Iron

[AKincer 6]

Very helpful guys - I should have a chance to look at it this weekend!

[Save Old Iron 1,563]

For a better idea why a starter relay can intermittently work and then sometimes cause issues, the following are a few images of a dissected relay. If you are interested in more detail, search for "relay autopsy" and it should take you to my original thread posted a few years back.

 

 

 

 

 

The copper "disk" is forced into the two copper studs when you engage the START switch.

 

 

 

 

After years of use, the disc and the studs become pitted and less conductive.

 

 

 

 

 

 

Sometimes the copper disc can be flipped over for a new surface

 

 

 

 

and the terminal posts spun around 180 degrees to use new copper on the bottom of the terminals where they contact the copper disk.

 

 

Edited May 9, 2015 by Save Old Iron

[AKincer 6]

Well I didn't disect the old solenoid (like Save Old Iron did), but I did replace the solenoid as I noted voltage drop under load that was higher than I liked.  I was seeing about .5-.6 volts across the solenoid posts while spinning the starter.  I replaced with a new solenoid and found the voltage drop to be steady at .05 volts across the posts.  Now it spins over and starts just fine.   My guess is that these big Kohlers need everything working just right.  On the smaller engines, maybe the .5 volt loss wouldn't cause a problem, but on this guy it needs everything it can get.  Seems to be working fine for now.  Will report back if anymore problems.  Thanks to all for you help!

[Save Old Iron 1,563]

Well done. You isolated an issue with logical troubleshooting instead of guessing and waiving your wallet over the problem.

 

You can also use that exact same voltage drop technique to check the quality of the battery cables. You may find additional 0.5 volt drop(s) across both battery cables or the battery ground cable bolted to the chassis.

[Save Old Iron 1,563]

On the smaller engines, maybe the .5 volt loss wouldn't cause a problem, but on this guy it needs everything it can get.

 

The .6 volt drop was more than likely an average drop seen by your voltmeter. I can guarantee the drop during the compression cycle in the engine was 2 or 3 times the average drop.

[oldredrider 2,547]

The big block Kohler, especially the K341, needs all the amps you can provide to get them at a good spin. The cheaper lawnmower solenoids won't (for very long) have the a$$ to carry the load.

I've been using Ford solenoids with no problems. Auto part stores carry them...just ask for a 1980 Ford solenoid.

[Save Old Iron 1,563]

Well I didn't disect the old solenoid (like Save Old Iron did),

 

Take it apart - you know you want to.

 

[RJR49 121]

You might try using a jumper cable to bypass the solenoid. That would give you an  idea if the problem is the motor or the wiring

One more thought. Given that the 13 tooth starter must have the same pitch as the 10 tooth to engage the flywheel. The mount has to be different to be able to swap. Although I suppose you could probably shim the 13 tooth. 

 

Still one more. Given the same motor the 13 tooth will have to work 30% harder. That has to mean the motor will get pretty hot pretty fast. Only having pics to judge by they appear to be the same size motors

 

any thoughts would be appreciated since I'm thinking of replacing the starter in my C-160. Given the price of OEM motors recommendations would be appreciated also

 

Edited January 20, 2017 by RJR49
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