Huge current draw from Kohler engine

[Charles in Aus.]

My old John Deere STX38 is powered by a Kohler Command 14 single cylinder engine . Over the last few months it has become slower and slower to turn over at start up . This trip to the farm saw it refuse and the current draw made the spring on the jumper lead glow red hot before I realised it was happening .
My first thought was poor earth connections so I undid and cleaned them all . Marginally better but still a poor rotation on start . Direct current to the starter helped a little but not significantly.
Could the starter be causing this huge current draw ? Is it worthwhile removing it and if so what should I look for ?

 

[guido]

Charles in Aus,

It probably needs the valve lash adjusted.
Kohller website will let you download the
proper manual,

Guido.

 

[Bret4207]

Yup, the starter could surely do it. The bushings/bearings going bad can cause that easily.

 

[cwtech]

I agree with Bret.

Dismantle the starter and correct a mechanical problem before it cooks the armature!

 

[wore out]

(quoted from post at 04:55:53 05/21/21) Charles in Aus,

It probably needs the valve lash adjusted.


Guido.

That was my first thought, as well, then I remembered that particular engine has hydraulic valve lifters and a non-adjustable valve train.

 

[wore out]

(quoted from post at 23:52:00 05/20/21) My old John Deere STX38 is powered by a Kohler Command 14 single cylinder engine . Over the last few months it has become slower and slower to turn over at start up . This trip to the farm saw it refuse and the current draw made the spring on the jumper lead glow red hot before I realised it was happening .
My first thought was poor earth connections so I undid and cleaned them all . Marginally better but still a poor rotation on start . Direct current to the starter helped a little but not significantly.
Could the starter be causing this huge current draw ? Is it worthwhile removing it and if so what should I look for ?

"the current draw made the spring on the jumper lead glow red hot"

That part is explained by one "jaw" being connected to the cable lead and the other jaw making contact with the battery terminal causing the current to flow through the spring, quality jumper cables have a wire braid connecting the jaws to prevent this.

As to the rest of it, test the battery, it could have a shorted cell or two, if not, the permanent magnets inside the starter's "belly" MAY have come unglued and are binding the armature.

 

[guido]

Charles in Aus,

If the mower is more then 10 years old, it may be the starter. The brushes get worn down and that makes the
starter draw lots of amps. The magnet type starter will do the same with loose magnets,

Guido.

 

[Geo-TH,In]

X2

 

[Charles in Aus.]

Thanks all . The venerable machine is 26 years old now and up until now has given very little trouble.
Next trip to the farm i will remove the starter . If parts weren't so expensive for John Deere equipment here I'd just buy a new one and swap it over. Well over $200 here and yet $70 in the US .
The cost of not actually making anything in Australia anymore .
Still I have a chance to keep the old mate going , really useful for pulling a little trailer full with chainsaw , fuel , oil and felling gear .

 

[guido]

Geo,

Not all Kohler engine have hydraulic lifters as you know.

But a think it more likely that the starter needs attention.

He is one of the few that will let us know what he finds,

Guido.

 

[Charles in Aus.]

Thanks for that explanation Wore Out . It makes perfect sense and it did puzzle me as to why that happened .
Ruined the spring completely , the clamp now flops about like a shag on a rock .

 

[Geo-TH,In]

Very easy to check valves.
My 20 hp command has hydraulic lifters.
Not sure if my 14 hp has hyd lifters.

 

[Charles in Aus.]

Despite our recent lock down I managed to get to the farm and take the starter off the Kohler Command engine . I dismantled it and found the brushes and bushes to be in good enough order .

But , when I withdrew the armature the permanent magnets came with it . Full marks to Woreout for suggesting that as a possible fault .

There is a little rubbing on one side of the armature but no damage to wiring that I can see .
Big question ; what do I use to stick them back on ? It looks as if there is very little clearance so it would need to be a thin adhesive .

 

[Bob Bancroft]

In a similar situation, I cleaned the housing with a cylinder hone. Degreased and primed everything. Made wood shims to hold
magnets in place. Used a 'Loctite' material. It was a waste of time.

 

[Charles in Aus.]

That's disheartening Bob . I was thinking of using some type of two part epoxy adhesive .

 

[Bob Bancroft]

There's got to be some material for the job. I don't know what it is. It's got to be strong, but very thin, I would say.

 

[Mule Meat]

Good magnet adhesive.
Clean them with Loctite755
Loctite 638 (adhesive) and you will need Loctite SF 7649 to activate it.

This post was edited by Mule Meat on 07/20/2021 at 06:31 am.

 

[Geo-TH,In]

Check valve clearance on all overhead
engines. One value acts as a
decomposition valve when starting

 

[Charles in Aus.]

Thanks Mule Meat

I'm not allowed out other than to buy food and essentials at the moment due to our latest lock down regulations but I will do that as soon as I can .
My earlier estimate of the cost of a replacement starter motor was way off . A genuine Kohler starter from John Deere here in Australia is well over $400, plus taxes and freight . After market replacements about $275 .
Well worth mucking about with some glue to try and repair it .

 

[Charles in Aus.]

Bob , what type of Loctite did you use ?

 

[Determined]

(quoted from post at 02:09:23 07/19/21) There's got to be some material for the job. I don't know what it is. It's got to be strong, but very thin, I would say.

With great success (repair was done 10+years ago) I used JB Weld to secure a set of magnets that had come off like yours did.

Cut up a few pieces of wood to properly space and locate the magnets.
A couple of strips of wood for protection of the magnets along with some c-clamps will hold everything tight until it dries.

Once you mix up the JB Weld you can thin it with some methyl hydrate so you can apply a thin uniform coat on the magnets.

Of course make sure everything is cleaned well first.

 

[Charles in Aus.]

Thanks for that Determined

 

[Ozlander]

$37.00 on E-Bay, don't know what shipping would cost.

https://www.ebay.com/itm/2903438516...MIiOCC8tf58QIVjLfICh2G9AS7EAQYBCABEgIyJPD_BwE

 

[Charles in Aus.]

Six months on and I was finally able to return to the farm after travel restrictions were lifted .
The repaired starter motor works very well . I used Gorilla glue , as loctite and other alternatives were out of stock during lock down .
The grass was a metre high and took three days to cut . At east five starts if not more a day without a problem .
Thanks to all that contributed .

 

[Determined]

(quoted from post at 02:54:06 11/29/21)
Six months on and I was finally able to return to the farm after travel restrictions were lifted .
The repaired starter motor works very well . I used Gorilla glue , as loctite and other alternatives were out of stock during lock down .
The grass was a metre high and took three days to cut . At east five starts if not more a day without a problem .
Thanks to all that contributed .

Good to hear it is working well for you.

It's always a good feeling when one can spend a bit of time versus a bunch of money to solve a problem.

Sounds like you had a mountain of mowing on your hands.