Kohler 8hp magnum find

[njdpo 6]

Hi all,

    Poor college dad here (running on a lean budget)

 

    I have a wheel horse Commando 800 with a very tired Kohler 8hp K-series (k181) in it. It runs, but severe carbon buildup has significantly eroded the top of the piston. 

    Last week I went to a flea market and found a newer Kohler 8hp Magnum (with the side tank). Its throttle assembly is below the carb – im thinking it was on a log splitter, or power washer maybe (dont know / dont care)??

 

    The $10.00 motor looked mostly complete, upon a quick visual inspection I see
    1)    the crank turns
    2)    the block had reasonably clean oil in it.
    3)    The link between the governor arm and the carb isn’t connected properly.
    4)    The fuel filter is broken, and the fuel line appears to be original – very dry rotted.
    5)    The muffler is missing (just an open pipe coing from the block.
    6)    Electric start, no pull start on this unit.
    7)    I don’t have an air filter assembly, but I think I might be able to use the air filter assembly from my older K-Series 181 (from the wheel horse commando 800)
    8)    The sticker on the side of the shroud is missing every detail, no SN, no model - It’s basically a shiny sticker (sigh).

 

Q: Does anyone know of any other place on the motor that might have the model/SN? 

 

Q: I’d like to see if I can get the governor / carb linkage connected properly. The governor arm has a large, and a small hole in it. The linkage rod won’t fit into the small hole, so I assume it went into the large hole with some sort of clip or bushing.

    

Q: Is it possible to test start the motor without the governor being attached to the carb?

If so - I could potentially use my jumper cables to see if it’s got spark, and see if it sputters to life.

 

Q: I was told the owner of the motor may have had problems with the starter motor (the story was very vague - so i expect something to be wrong), I suppose I could move starter motor from the K-Series 181 over to the M-motor to temporarily test it… does that sound reasonable ? 

 

Q: if it runs I wonder if I can easily migreate my existing k-series carb bracket and cable to the new M-series ... and drop it into my commando 800 ? (yes / no / maybe) 

 

If I could see the potential for a running motor, I can invest in it …

I’m mechanically able and have most of tools required to get it into service.

I was thinking if runs – id pull the head and have a look at the piston and bore…

Just to see what im working with (from the top end). 

 

Any advice would be greatly appreciated.

(will try and post a few pics - when i get home) 

 

thanks dave.
    

[kpinnc 12,065]

5 hours ago, njdpo said:

I might be able to use the air filter assembly from my older K-Series 181

 

Yes you can. 

 

5 hours ago, njdpo said:

Is it possible to test start the motor without the governor being attached to the carb?

 

I would not. The engine could run away and throw a rod before you can stop it. 

 

Also- I believe the starters are not interchangeable. On the big blocks at least, they bolt differently. 

 

 

Edited May 21 by kpinnc

[wallfish 17,000]

Many of those parts will interchange so use the stuff from the 181 to get the carb connected. ( The carbs will swap too) Set the governor per manual.

And fire it up! I love those little Kohler 8s because it seems they all want to run

Yes it's a good replacement engine for your tractor. You can ditch the side tank and use the tractor tank

[clueless 3,001]

First question, is the shaft round and at least 3" long, or is it tapered?

 

[Fordiesel69 263]

18 hours ago, njdpo said:

 

 

Q: Does anyone know of any other place on the motor that might have the model/SN? 

Negative.

 

Q: I’d like to see if I can get the governor / carb linkage connected properly. The governor arm has a large, and a small hole in it. The linkage rod won’t fit into the small hole, so I assume it went into the large hole with some sort of clip or bushing.

Swap your arm and linkages over, including the carburetor.  (if you have brass pipes you may need to also swap your fuel pump)

    

Q: Is it possible to test start the motor without the governor being attached to the carb?

If so - I could potentially use my jumper cables to see if it’s got spark, and see if it sputters to life.

The magnums need not a single wire attached anywhere to get spark, yes you can, and to kill the engine place a rope over the spark plug wire first before you start it.  I would advise having an assistant so you can control the throttle flap on the carb while your buddy connects the jumper cable to the starter.

 

Q: I was told the owner of the motor may have had problems with the starter motor (the story was very vague - so i expect something to be wrong), I suppose I could move starter motor from the K-Series 181 over to the M-motor to temporarily test it… does that sound reasonable ? 

Magnums and k series starters are not interchangable without swapping the backing plate, and if you do that you will not have magneto ignition and you will need a machine shop to drill and machine holes in the block to mount the points, and most likely depending on how old it is, you may need to swap the cam shaft to be able to use points.  Not worth it, just fix the existing starter.

 

Q: if it runs I wonder if I can easily migreate my existing k-series carb bracket and cable to the new M-series ... and drop it into my commando 800 ? (yes / no / maybe) 

Yes this is doable.

.

If I could see the potential for a running motor, I can invest in it …

I’m mechanically able and have most of tools required to get it into service.

I was thinking if runs – id pull the head and have a look at the piston and bore…

Just to see what im working with (from the top end). 

 

18 hours ago, njdpo said:

 

Any advice would be greatly appreciated.

(will try and post a few pics - when i get home) 

 

thanks dave.
    

 

[Fordiesel69 263]

I would also consider the possibility of you fixing it up, make it look purdy, and sell it on CL or FB, then use that money to restore your original tired K181, or use the money to get a period correct engine that is is good shape.  

[Moparfanforever 848]

I took a few pics that may help you. 

 

You will also need a new ignition switch to use with the Magnum because you have to ground the mag coil to shut the engine off. Or just wire it like I did with a push button starter switch and a toggle switch to shut it down. You cannot put 12 volts to the coil because you will fry it. 

 

I think the Magnum carb and K carb have different bolt patterns where the air cleaner bolts on, I think. No biggie fixing that. 

 

 

[Moparfanforever 848]

You will also need to see it has a 15 amp stator that uses a voltage regulator or the stator that uses a diode for charging. 

 

Someone with more knowledge than me on that will have to chime in as I need to put a diode on my tractor. 

[njdpo 6]

On 5/22/2024 at 7:41 AM, clueless said:

First question, is the shaft round and at least 3" long, or is it tapered?

 

Hi yes - the shaft is straight and im hoping my pulley from the K181 will move over to the M181.

without much issue? 

I think there is a bearing assembly on that clutch/pulley system - im thinking that bearing gets a refresh while i've got the pulley in the middle of the swap. 

 

thanks again - dave

[njdpo 6]

19 hours ago, Moparfanforever said:

I took a few pics that may help you. 

 

You will also need a new ignition switch to use with the Magnum because you have to ground the mag coil to shut the engine off. Or just wire it like I did with a push button starter switch and a toggle switch to shut it down. You cannot put 12 volts to the coil because you will fry it. 

 

I think the Magnum carb and K carb have different bolt patterns where the air cleaner bolts on, I think. No biggie fixing that.

 

big THANKS MoperFanForever (me too - ive got a 1969 SuperBee)

 

1. it seems like your tractor there looks very much like my commando 800.
2. Ive been thinking of keeping the side tank as seen in your picture - I wasn't sure I could squeeze it into the commando. Currently my fuel tank is high up near the dash and its starting to get brittle/fragile, Ive already replaced one fuel tank and can see the current degrading slowly. I also like that you pulled the old tank - its nice and open in there ... mine gets full mice nests and acorns every year ... but if it was open - it would be easier to clean. I might even fit in a small metal stash box to hold a few minor tools. (that or I could warm up my beer in there) 
3. if you have any - could you posts a pic of the muffler setup, and the dash side that faces the seat? I wanted to see what you did for a muffler ... Ive got a pepper can on mine now... but kicking around the idea of other options... (im sure the cost will have me moving over the pepper can from k181). 

4. You will also need to see it has a 15 amp stator that uses a voltage regulator or the stator that uses a diode for charging. 

   Someone with more knowledge than me on that will have to chime in as I need to put a diode on my tractor. 

   Im not very electrically inclined (mechanically im good) so im already getting a little concerned about the electrical mods I might need to make (i'll need to plan that out carefully). I assumed for the early part of this experiment that I could use the ignition switch thats on the shroud of the engine. Im gonna have to have a look at the commando 800 schematics i guess, and read up on the 15 amp stator / voltage reg vs the diode design. 
5. I notice the governor linkage in your pic has a dog leg in it ... mine ends in a 90 degree bend - seems to expect being snapped into a nylon bushing that snaps into the large opening of my governor arm. I saw this setup online somewhere.
6. the pics below show the sloppy linkage connection - and where the nylon clip/bushing/doo-dad goes...  And that carb is full of ... not sure ... and THAT is why you leave the air filter on ! 

 

 

 

[Moparfanforever 848]

You have a voltage regulator bolted to the blower housing, I think that means you have the 15 amp stator. 

 

I bought this tractor and it was a roller and I think it left the factory as a Raider 10.

 

The battery is a tight fit, you will need your posts as pictured if you leave the tank on the engine. 

 

The muffler is a WH muffler from big block Kohler I think. The pipe coming out of the engine for an 8HP is shaped different. 

 

The dash that was on it had the push/pull cables on it with the locking throttle cable which I am not a big fan of. I changed it to this style dash with this style cables which I like better. The push button starter switch is on the left of dash. 

 

Hope these help and NICE BEE !!! Tough to find. 

 

 

 

[Moparfanforever 848]

Those throttle linkage clips are still available, isavetractors.com had them at one time. You can usually get them anywhere that sells Kohler parts. 

[Fordiesel69 263]

How is the project coming along?

[njdpo 6]

On 5/30/2024 at 1:11 PM, Fordiesel69 said:

How is the project coming along?

Not so well, was on vacation the last week,

and came home to unexpected mower deck issues with my ingersoll 444 (cracked pot-metal spindle housing).

 

Last week (at the hotel) I was looking at a parts diagram for a M-series 181. and found a diagram that had the clip for the governor arm.

and then my laptops battery died (sigh) ... back to the pool for another beer...

Ill start looking at those diagrams again to find the basic parts i need. 

 

- Thx Dave 

[njdpo 6]

well i found the clip i need for the governor arm ... the exploded parts diagrams I was looking at showed the part - but their crude pictures left me wondering how the part fit into the governor arm... A search on the  Google-A-Tor machine for "kohler M8" shows me a nice pic of how it all fits together.

 

the pics above show the carb throat it loaded up with dirt so im gonna try and pull it - and search for a rebuild kit. 

does anybody know if that carb looks stock? im seeing several versions of the carb rebuild kit for that unit (costing between $10~$50).

Does anyone here know of a recommended part number ? that would be great . ( maybe some / some dont - have gaskets for the air cleaner ? ) 

 

thx dave 

 

(the pic below is not my motor) 

as seen in this posting - www.wheelhorseforum.com/topic/106421-kohler-m8-throttle-linkage/

 

 

[njdpo 6]

well the carb is trashed.

the bowl and the entire inner assembly was completely filled with rust.

the bowl has several holes in it...

the venturi was so plugged up i had to soak the carb in oil eater and scalding water - and the mud from the bees that live in there still was hard to cleanup ...

the brass metering rod is visually damaged and im not able to remove it ... ive even tried soaking it with PV blaster... and heating the body with a torch...

shes stuck good. 

 

its a walbro ... and its got serial numbers

 

ive got the carb off and looked in the intake and saw some stuff in there too...

started to turn the crank and she spins ...

but the compressions is low ...

and its hissing as if a valve is stuck open... 

 

Im going to take a pause on replacement of the carb ...

and focus on getting the head off and getting a visual of the cylinder. 

 

Also im having some trouble gettingthe tank off this motor ... seems that maybe the starter needs to come off first ?

 

- dave

Edited June 10 by njdpo

[njdpo 6]

so i got the head off ...

and its looking pretty good in there.

 

i sprayed the carbon deposits with a penetrating fluid called "nuts off",  (like a pb blaster type of product.) 

im not sure about pb blaster product , BUT "nuts off" turns the carbon deposits into a gooey slime which was easy to remove with a paint scraper. 

 

so after cleaning everything up i see the piston is a std size . and i can even see cross hatching in the bore...

so maybe my $10 investment wasn't a total waste.

 

 

Edited June 10 by njdpo

[Fordiesel69 263]

That engine is worth fixing.  Probably low hours and just sat forever.

[njdpo 6]

" engine is worth fixing" - I think so too ... 

 

I was thinking of using the carb from my older K181 (which is in the tractor now )

but I see that the carb linkage is very sloppy in the carb body (very worn).

 

So Im thinking I need another carb to do this right. 

Does anyone have any recommendations on a replacement carb ? 

Ive seen where people are using the clone stiff with varying levels of success - some are even swapping the older brass linkages into the new body. In my case the choke Linkage is damaged ... so I dont have that option available to me ... 

 

Oh also - I need a head gasket has anybody used the stens head gasket ... or perhaps recommend another brand / part # ? 

Any advice on the carb & gasket  situation greatly appreciated.

 

- Dave

[Fordiesel69 263]

Carb:  I have had decent luck overall with clones.  I have not had one on a K181 before so I would hate to say yes, go ahead youll be fine.

 

Head Gasket:  Use whatever brand has a fire ring.  Not the soft graphite one that falls apart when you touch it.  When using the stens, the only drawback is they need torqued 2 or 3 times after some heat cool cycles.  

[njdpo 6]

piston, valves and surrounding area, and head all cleaned up, new head gasket, and back together.

 

removed the breather/valve cover yesterday and found a sizable about of rust in that area buit up round the intake valve area.

I scraped it clean and blew it out... but how did the rust collect in this oily area ?

 

upon closer inspection of the air intake into the block its rather orange /rust colored in there. 

Since that carb was so clogged up, and rusted as bad as it was Im assuming there was lots of water in the gas tank, or the missing air cleaner let the rain and snow into the carb body. 

 

I think the water was coming in through the carb - sitting in the intake tube - and slipping past the valve gear and collecting down into the area where the valve springs live. the Springs look clean (no rust),,, at first the intake pushrod looked rusted - but after working the area with a old paint brush and kerosene it all cleaned up pretty well.

 

BUT I cant measure ANY valve lash and Im wondering if this is due to a compression release setup ? 

 

- dave

 

[njdpo 6]

still inspecting and cleaning various parts, and preparing for reassembly. 

the guy who I bought this from had mentioned possible problems with the starter (vague).

and before I put it back together - I want to test the 

 

WITHOUT the solenoid in the test:

i took my jumper cable and tried to test the starter. 

- black cable to the Battery:Neg *AND* starter motor housing. 

- Red cable to the Battery:Pos   *and* to the post of the starter motor.

 

no sparks, no clicks, nothing ...

With the amount of rust in the valve spring area, i am suspecting this this motor has been left outside in the rain/snow... or a possible flood.

and i am wondering if the starter saw some water exposure and maybe the brushes are stuck ?

 

The cylinder bore still has the cross hatching on it - so I dont think this engine has seen a lot of wear and tear. (and the starter motor - which appears to be original),  

Hoping the electric starter motor, is needing a little love (maybe feeling a little stuck in the brush area)?  

 

any advice greatly appreciated

 

Dave

 

[njdpo 6]

got the starter motor apart, and cleaned it up

 

saw a fair amount of dirt (from where - i cant say).

I saw no rust, so it seems this part of the engine didn't see any water like the valve cover. 

 

The starter motor had 4 brushes in it and I had a heck of a time putting back together with those 4 sprung brushes wanting to pop out. 

 

anywho - I put it back on the engine and hit it with the jumper cables,

... drum roll please ...

 

Engine turned over +1 

and I see a nice FAT spark on the plug +1

 

next stop... find me a carboNator. 

any advice greatly appreciated

 

dave

[oliver2-44 9,756]

On 6/15/2024 at 5:45 AM, njdpo said:

BUT I cant measure ANY valve lash and Im wondering if this is due to a compression release setup ? 

 

The compression release should not effect your checking valve clearance.  The compression release only works when the cam is pushing the valve UP.   If the valve is all the way closed  the compression release does not come into play.  

Try sawing a feeler gauge back and forth between the valve and tappet to clean it out.  I know this is hard to do with a thin feeler gauge.   Maybe some dental floss would work.

I know n the K series the tappets are not adjustable and you have to grind the end of the valve.  Unsure on the magnum, but you would see the tapper having a bolt heat at the top of it if it were adjustable.

[njdpo 6]

19 hours ago, oliver2-44 said:

The compression release should not effect your checking valve clearance.  The compression release only works when the cam is pushing the valve UP.   If the valve is all the way closed  the compression release does not come into play.  

Try sawing a feeler gauge back and forth between the valve and tappet to clean it out.  I know this is hard to do with a thin feeler gauge.   Maybe some dental floss would work.

I know n the K series the tappets are not adjustable and you have to grind the end of the valve.  Unsure on the magnum, but you would see the tapper having a bolt heat at the top of it if it were adjustable.

 

hmm... living in ignorance was bliss for a while ... 

re: Try sawing a feeler gauge back and forth

yeah thats what I was doing ...

 

the strange thing about this story is the condition of that cylinder being so clean (with the cross-hatch marks)

left me thinking the engine didnt see many service hours ... possibly a lucky find ??

 

im wondering if the rust in the valve gear area has things stuck up a bit...

Valves are moving freely ... maybe the pushrods aren't happy because of the rust I found in there...

im gonna shoot it up with some pb-blaster and roll the motor over a few times and see if I can discover anything ... 

and as you mention the k181 doesn't have adjustable tappets ... im 95% sure the M8 doesnt have them either ( i will look again).

 

It seems odd that both valves have ZERO slop in them ... suggesting what ? 

- came from the factory like this ? 

- someone was in there and replaced the valves (improperly) ? 

- something stuck in the valve gear (because of rust) ?

- something big and ugly waiting for me down in in the lower half of the block ? (i really dont want to open up the block - if i dont have to) 

 

- dave