19 HP Kohler engine - on a Troy bilt 6605

[bertsmobile1]

Degrease the crank shaft then clean the aluminium off with hydrochloric acid ( muriatic is the same just a lower grade )
Don't leave it sit in there for hours it should dissolve off in about 10 minutes.
neutralize the the acid bath with pool chlorine and it will be safe to tip down the drain ( might be illegal in some places ) .
Then ake some close ups of the big end journal.
usually they cleanup OK but if there are grooves into the surface deep enough to catch your fingernail the journal is toast.
Some times a light polish will be OK but generally it is new crank time.

Once we have determined if the crankshaft needs replacing then it is time to start adding up the parts required and come to a decision..
Was there a rod under the bottom counterweight ?
What does the bottom of the crankcase look like.

And congratualtions well done thus far .

 

[Kba9]

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Worth mentioning that the piston connecting rod is cracked and both sides. I took a picture of the crank, is this where I should be checking for deep groves, where the connecting rod meets the crank right?

 

[Hammermechanicman]

Bert gave you a good way to try and save the crank. If you do go the acid route after you remove the aluminium you can use red scotchbrite to clean up the crank. Don't use sand paper or Emery paper. You don't want to remove steel, you just want to polish any high ridges from scoring. After that bolt the new rod on and see if it tuns smoothly on the crank. If it doesn't you need to polish a little more. If it does turn smoothly you can get a product called plasiguage to check the clearance. I have saved a few engines with less than perfect crank journals after they seized a rod.

 

[bertsmobile1]

Don't look all that bad.
Rod is obviously deceased.
Nothing lurking in that oil on the bottom ?

 

[Kba9]

Don't look all that bad.
Rod is obviously deceased.
Nothing lurking in that oil on the bottom ?

Not that I can tell

 

[Kba9]

Not that I can tell

The shaft seems to be in pretty good condition. Should I just order a new piston rod and start putting things back together. Also do I have to lube the shaft up and how do I re-time it.

 

[bertsmobile1]

BEfore you go ordering parts we still have to work out why the counterweight broke free and was side on in your engine.
It was the counteweight that caused the rod to break but something else allowed the counteweight to shift from it's normal position.
Despite being an earlier model, your counterweight should only be able to move the same as the one in the photos I posted of a latter model back in reply # 18
So we need to see the bottom of that crankcase without any oil in it and the underside of the top closure plate .
No use buying a new con rod & piston if the counterweight does the same thing the minute you fire up the rebuilt engine.
And are you sure t needs a new piston ? and not just a rod ?
Was there damage to the piston ?

I ask you this because Kohler parts are no where near as cheap as Briggs parts and you can easy run up $ 300 to $ 400 in part and still end up with a broken engine.

Counter weighs would usually only break away if the governor failed and the engine drasically over reved or the bolt that holds the two halves together vibrated loose & the two halves parted company.

The two important questions are always
What has failed ?
&
Why did it fail ?
So at the minimum you will need :-
Con rod
Balance weight tie bolt
Gaskets & seals
Bottle or spray can of Assembly Lube .

Looks like the counterweight is assembled onto the crankshaft before the crankshaft is installed into the crankcase .
As for timing,
The cams hare the same and the cam gears have a timing mark for both inlet & exhaust
The gear you prised off the crankshaft has 2 timing marks on it
So it is just a case of aligning the dots

 

[Hammermechanicman]

When you assemble thw engine if i remember correctly you put the bottom counter weight on the crank and install in crankcase. Then install piston and rod into block and attach rod to crank then install top counterweight link and bolt that hold counter weight. Been a while but i think that is how i did it. Kohler thinks their parts are special and over price them. Just one more reason to dislike Kohler. Price an OEM carb sometime.

 

[Kba9]

Ok so i started taking a look at it again. I noticed that there was no ring on the top counter weight and it was stuck in the crank. I managed to get it off but there's metal still stuck on there. Do you believe this is the problem? And is the crank done?

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[bertsmobile1]

IT should prize off but of course it is stuffed.
The bearing is not listed as being a repacement part.
SO you will need to take both the cleaned crank shaft ( bearing removed ) and the counter weight to a bearing shop.
There will be a replacement available but you might need to trim it to width.

Sort of glad you found that because it explains the out of position counterweight.