Share Your Small Engine Repair Horror Stories

[Bison]

I had a 12 hp cast iron kohler explode in my 112 JD lawn tractor on me a couple years ago.
The conrod seized on the crank pin(lack of oil ) and broke and in the process took out part of the cylinder bore and a whole side of the block,including breaking the startermotor in two.
The sudden shock also caused the flywheel to split.
The pieces were spread out across the lawn,some pieces i never found.:confused2:

 

[Bison]

Try a new pin, i used a( i think 3/16") steel dowel cut to lenght when i lost the original aluminum pin when rebuilding one of mine.

 

[ILENGINE]

Yes it could be a bad coil, but depending on the model and spec number, it could also be the points plunger. I'll have to do some research to see if I still have the bulletin from back in the 70's (I think) about this problem.

That could be a possibility. he also said that he replaced the head gasket. Did he also replace the head bolts. The old K series will have head gasket leaks if the head bolts were not replaced. will act just as he described.

Something about the elasticity of the head bolts won't match the cast iron aluminum expansion interface causing a temporary loss head bolt situation after the head and block warm up.

 

[DaveTN]

Thanks IL ENGINE, and RIVETS and BISON. I'll get the model #s off it and post them.
NOTE: K-301

4765


I appreciate your help but am basically at my wits end and tired of worrying with it. As IL said, it could be the head bolts. Never thought of that since it was a cast iron engine. I believe the head bolts are steel. Automobiles with steel blocks and aluminum heads have that problem and the bolts have to be replaced every time the heads come off!! I will fire it up again and when it starts to quit, check it for compression. I know there are two carburetors made for that series engine. One has that LONG main mix needle on TOP. I believe it's a variable jet. The other one has the shorter mixture screws on it. A Walbro it seems. I believe it's a fixed jet type. I know the shorter screw type won't rev up as well due to fuel/air mixture and volumetric efficiency , fixed jet etc. Those egg head formulas for racing engines and rpm/torque curves etc. THANKS GUYS!!

 

[Rivets]

One of these sites may help you. Still looking for the plunger bulletin.

http://www.kohlerengines.com/onlinecatalog/pdf/tp_2379.pdf

Kohler Engines: Owners and Service Manuals: Manuals and Maintenance

 

[Bison]

Thanks IL ENGINE, and RIVETS and BISON. I'll get the model #s off it and post them.
NOTE: K-301

4765


I appreciate your help but am basically at my wits end and tired of worrying with it. As IL said, it could be the head bolts. Never thought of that since it was a cast iron engine. I believe the head bolts are steel. Automobiles with steel blocks and aluminum heads have that problem and the bolts have to be replaced every time the heads come off!! I will fire it up again and when it starts to quit, check it for compression. I know there are two carburetors made for that series engine. One has that LONG main mix needle on TOP. I believe it's a variable jet. The other one has the shorter mixture screws on it. A Walbro it seems. I believe it's a fixed jet type. I know the shorter screw type won't rev up as well due to fuel/air mixture and volumetric efficiency , fixed jet etc. Those egg head formulas for racing engines and rpm/torque curves etc. THANKS GUYS!!

I have rebuild a couple of these kohlers and always reused the headbolts,I never had a problem.
A sticky fuel needle valve could cause stalling if it won't open when the float drops and the engine demands fuel, but when it sticks it usually stays stuck and prob won't open again without opening the carb.
Is the liftpump working correctly or maybe the tankvalve and inlet filter is full of dirt and to little fuel is making it to the carb,...did you check that?
After a little sitting it will have filled the carb enough again to run for a bit.

 

[Bison]

only other thing i can think of is the exh valve sticking open when the engine heats up.(carbon build up in the guide)
Or maybe it needs adjusting(not enough clearance)

Good clean wel adjusted points is very important as well.

 

[DaveTN]

Thanks Rivets, I downloaded a K series manual for that engine. Bison, it could be a sticky valve causing it to lose power and die when it gets warmed up. Or again a sticking needle and float like you said. Did you guys ever wish you had a clear glass or plastic float bowl so you could actually SEE what's going on at times? LOL I have!! I'll check the float again. I by passed the fuel pump and used a tank above the carburetor arrangement. I know the tank was clean because I loaned it to another guy who has the same identical motor on a FORD LGT and is now mowing with it. Thanks for the suggestions guys. Dave

 

[Bison]

I would hook the fuelpump up again,they run better under load(more fuel)

 

[robert@honda]

Note small engine, but supreme screw-up:

Had an nice '72 Corvette with a 4-speed. Ran fine, and I bought my first set of drive-up ramps so I could do my own oil changes. Bought a Haynes repair manual.

One day, was changing the oil and leafing through the manual looking for anything else I should be checking under the car. "Transmission gear oil Level" caught my eye. Okay, seems you just remove the inspection plug from the side of the transmission, and the gear oil should be right up at the same level as the hole. Easy enough.

I unscrewed the plug, and yikes! A BUNCH of oil drained out. "Golly!" sez I, "Wonder why this transmission has so much extra oil? It's only supposed to be filled up the the hole?" I let about a 1/2 to 3/4 of a quart drain out, replace the plug and was glad I checked! Sure was smart of me! Got all that "extra" oil out of there.

Of course, I failed to realize you only check the level of oil when the CAR is on a flat LEVEL surface. With those front wheels ramped up a good foot in the air, all that precious gear oil just flowed right onto the garage floor.

It took about 2 weeks, but the transmission finally self-destructed from a lack of oil. It was a painful, $1,100 (1982 dollars) lesson.

P.S.:
Was changing the oil in the wife's Mazda. Pulled the filter off, but neglected to notice the o-ring on the filter decided to stay attached to the engine, not the filter. Put on the new filter, and got it hand-tight as normal. The double o-rings left a nice 1/4" gap all around the filter (!).

Added 5 new quarts of Castrol, sat in the driver's seat with the car still up on ramps, and started the engine. Heard an "unusual" gurgle, and my eyes got real wide when I looked down and saw a ever-expanding puddle of fresh oil being pumped out of the gap and onto the garage floor. Took about 2 seconds to empty it. What mess!