No compression, maybe broken connecting rod

[68 raider 12 3]

Hello, I was mowing my lawn today with my 68 raider 9/12 ( not sure exactly what year no accurate serial numbers to work with) everything was going smooth and then the engine started to kinda sound like it was struggling then quit and a little smoke puffed out of the air intake. I thought I had blown the engine so I gave it one last turn of the key and it fired up no problem but when I got it up to mowing rpm the engine made a horrible clunk noise and just shut off. The engine still turns over freely but almost to free and now seems to have no compression. Any thoughts? Thanks. 

[daveoman1966 3,751]

Not sure...  Could be connecting rod or something else.  I have a good connecting rod for the Kohler K301 engine...you can have it for $25...SHIPPED.  I don't have the lower end cap for it.  Aluminum Connecting Rod and Wrist Pin here. 

[squonk 41,118]

Most likely broken rod and tore up crank. And possibly a cracked cylinder wall as well. Tore 2 k301's apart this spring with cracked blocks

[68 raider 12 3]

5 hours ago, squonk said:

Most likely broken rod and tore up crank. And possibly a cracked cylinder wall as well. Tore 2 k301's apart this spring with cracked blocks

I don't thing the crank, when I turn the engine over the flywheel spins and the shaft connecting to the pulley for the deck it all spins smooth, it just seems like the piston isn't moving so it won't fire.

[squonk 41,118]

1 minute ago, 68 raider 12 said:

I don't thing the crank, when I turn the engine over the flywheel spins and the shaft connecting to the pulley for the deck it all spins smooth, it just seems like the piston isn't moving so it won't fire.

The crank will most likely be torn up where the rod used to be connected to it.

 

 

[pacer 3,169]

7 hours ago, 68 raider 12 said:

was struggling then quit

 

That right there was your - usually - early warning signal! That almost always is the engine seizing, --- low/out of oil, clogged cooling fins, etc, its got so hot that it seizes! By restarting it and then.....  

8 hours ago, 68 raider 12 said:

horrible clunk noise and just shut of

 

And as you are guessing, its probably got some serious damage now. If it was caused by clogged fins, then there would be a chance it might survive after cleaning them, but its usually worn parts. It turns because the rod/piston is probably totally destroyed.

 

Break out the wrenches!!

[Handy Don 12,227]

10 minutes ago, pacer said:

Break out the wrenches!!

And prepare wallet for discharges....

[Gregor 4,846]

Don't forget the camera.

[68 raider 12 3]

31 minutes ago, Handy Don said:

And prepare wallet for discharges....

I've found rebuild kits online for 124 so not to bad

[squonk 41,118]

Don't order a thing until it's all tore down. If the block is busted, find another engine.

[oliver2-44 9,750]

 

29 minutes ago, squonk said:

Don't order a thing until it's all tore down. If the block is busted, find another engine.

You also may need to have the engine cylinder bored and the crank ground.

 

1 hour ago, 68 raider 12 said:

I've found rebuild kits online for 124 so not to bad

Then you would need the kit with the oversize piston and undersize rod.

 

[68 raider 12 3]

47 minutes ago, oliver2-44 said:

 

You also may need to have the engine cylinder bored and the crank ground.

 

Then you would need the kit with the oversize piston and undersize rod.

 

How would I know if the block is busted?

[oldlineman 1,481]

Visual inspection, should be obvious. Bob

[68 raider 12 3]

14 minutes ago, oldlineman said:

Visual inspection, should be obvious. Bob

Something that can be seen from the outside? Or is that on the inside of the engine? 

[squonk 41,118]

2 hours ago, 68 raider 12 said:

Something that can be seen from the outside? Or is that on the inside of the engine? 

Inside. look at that picture I posted. Rod hits the cylinder wall

Edited July 13, 2021 by squonk

[8ntruck 7,004]

2 hours ago, 68 raider 12 said:

Something that can be seen from the outside? Or is that on the inside of the engine? 

Most likely, the damage would be internal on the block.

 

You familiar with dye checking?  It might be worth purchasing a 3 can set of cleaner, dye, and developer.  Ought to be available at the local auto supply store.

[oliver2-44 9,750]

If you don't see an external new hole in the block, that a small good start, but you also need to look inside.  With the oil pan removed are their any pieces of metal in the drained oil or bottom of the pan? Then, look up at the bottom side of the piston and cylinder.  Are any pieces of metal cracked along the bottom of the cylinder.  your looking for something like shown in the second picture.  

7 hours ago, squonk said:

The crank will most likely be torn up where the rod used to be connected to it.

 

 

  Then unbolt the 2 bolts that hold the bottom rod cap around the crank.  The crankshaft round journal should look very smooth and shiny, not like the first picture. 

Take pictures of anything you find in the oil/oil pan and the bottom side of the cylinder and the crank journal and post them here for us to help you look at them. 

This will help determine how you move forward.  I.e. a scrap block or a trip to the machine shop for precision measurements.  If the machine shop see's anything questionable crack wise, they should have the stuff on hand to do a 'Dye Check"  for invisible cracks.

[John2189 453]

19 minutes ago, oliver2-44 said:

If you don't see an external new hole in the block, that a small good start, but you also need to look inside.  With the oil pan removed are their any pieces of metal in the drained oil or bottom of the pan? Then, look up at the bottom side of the piston and cylinder.  Are any pieces of metal cracked along the bottom of the cylinder.  your looking for something like shown in the second picture.  

  Then unbolt the 2 bolts that hold the bottom rod cap around the crank.  The crankshaft round journal should look very smooth and shiny, not like the first picture. 

Take pictures of anything you find in the oil/oil pan and the bottom side of the cylinder and the crank journal and post them here for us to help you look at them. 

This will help determine how you move forward.  I.e. a scrap block or a trip to the machine shop for precision measurements.  If the machine shop see's anything questionable crack wise, they should have the stuff on hand to do a 'Dye Check"  for invisible cracks.

My 16 hp broken rod. It had a chunk out of the skirt of the cyl like the second pic. Looked like it would not hurt anything, the crank was good so I bought a new rod and rings for it and put it together. Runs great. 

[squonk 41,118]

11 minutes ago, John2189 said:

My 16 hp broken rod. It had a chunk out of the skirt of the cyl like the second pic. Looked like it would not hurt anything, the crank was good so I bought a new rod and rings for it and put it together. Runs great. 

You got lucky. Cylinder wall could have had a microscopic crack that would have ruined you day.

[adsm08 2,059]

6 hours ago, oldlineman said:

Visual inspection, should be obvious. Bob

 

I was scrolling and read this as "vivisection", which is seemingly equally appropriate at this point.

[Howie 886]

My K301 has been running with a chunk out of the bottom of the cylinder since

about 1985.

[squonk 41,118]

Everyone who would run this block, raise their hand! 

 

 

 

[953 nut 55,229]

On 7/13/2021 at 9:44 AM, 68 raider 12 said:

I've found rebuild kits online for 124 so not to bad

First things first.   Before you buy anything you need to find out what has happened. Disconnect and cap the fuel line, remove the choke and throttle cables and unhook all wires going to the engine. Now remove the four bolts that attach the block to the oil pan and take a close look.         You can remove the two bolts that retain the connecting rod (if they aren't already broken) and remove the cylinder head. Now you can take a closer look at the crankshaft and cylinder.                DON"T BUY ANYTHING until you KNOW what you need!

[squonk 41,118]

Since it quit once and fired it back up so it would quit again it probably will look like this! 

 

 

 

[Mickwhitt 4,624]

Ouch!  Yes sounds like you will have a kit of parts for a con rod rattling round in the oil pan (sump).

Easy check is to take out the spark plug and see if the piston is moving up and down.

If not take off the head, see how things look in the cylinder.  You might be able to pull the piston out but it would take a bit of ingenuity to do that. You could then see the damage to the con rod then. That is when you will be removing and stripping the unit. 

Good luck.