A one trick pony

[WheelHorseSteve 56]

My C120 has been a great horse over the years but is doing something odd of late:

 

After getting it to start (which can be tricky), it runs well for ~2 minutes and dies (like the spark shut off). If I try to restart, it might catch and go for another 30 seconds before shutting down. It doesn't act like it's running out of fuel -- it feels more like a spark issue. The coil is a Bosch blue from Kirk's Engines and the condenser is either one of his special ones or an OEM Kohler one.  I'm also wondering whether the valve (clearances - or lack thereof) could be a part of this.

 

Based on these symptoms, where would you start? 

 

Thanks all!

-Steve

 

[kpinnc 15,689]

Remove the gas cap. See if it makes a difference. You never know. Dumping the carb fuel bowl is never a bad idea either. 

 

Condenser "usually" won't shut it down. Just makes it spit and sputter. But if you have specialized electrical components, I would start there. Swap only one at a time. Coil, then condenser. Plug, plug wire. If swapping a part makes no difference, put the original back before swapping something else. Clean your points with emery cloth. 

 

I'm sure you'll figure it out. 

Edited October 18 by kpinnc

[ri702bill 10,026]

Install an inline xenon bulb spark checker when running it. When it dies, do you have spark??

Edited October 18 by ri702bill

[953 nut 62,142]

14 hours ago, kpinnc said:

Swap only one at a time.

Words to live by.            

14 hours ago, WheelHorseSteve said:

The coil is a Bosch blue from Kirk's Engines

Is the coil equipped with an intermale resistor? If not have you adder an external ignition resistor?

[ri702bill 10,026]

  16 hours ago, kpinnc said:

Swap only one at a time.

Words to live by.            

[ri702bill 10,026]

  16 hours ago, kpinnc said:
Swap only one at a time.

Words to live by.            

Or die by.... My Engineering Supervisor (and his Boss) were sticklers for both details & data. When attempting to tweak or improve a process, you had best change only ONE thing at a time, then evaluate the results, if any, and write up a presentation with the findings. I caught grief once for changing two items in the same process; one at the beginning and one near the end. I did up one presentation with data showing no improvement at the beginning, but a substantial one at the end. That went on to be implemented and was recognized as a Cost Reduction. The Big Boss was not impressed - my Supervisor told me "Good job, never do it that way again!!"

[kpinnc 15,689]

1 hour ago, ri702bill said:

Or die by.... My Engineering Supervisor (and his Boss) were sticklers for both details & data.

 

For troubleshooting purposes, one component swap at a time is best. I'm an engineer myself, and the one rule is "redesign the rules"!

 

But again when looking for the culprit in any troubleshooting- changing one part and putting the original back if no change before moving to the next does indeed work. 

 

 

[adsm08 3,616]

5 hours ago, kpinnc said:

the one rule is "redesign the rules"!

 

I'm a field tech. I thought the One Rule was to can the whole unit, replace the largest assembly possible, and let the guys who screwed up the original design figure out what went wrong.

[wallfish 18,625]

55 minutes ago, adsm08 said:

 

I'm a field tech. I thought the One Rule was to can the whole unit, replace the largest assembly possible, and let the guys who screwed up the original design figure out what went wrong.

Yeah, if it's all covered under warranty. Otherwise that rule is just screwing the customers over!

[adsm08 3,616]

2 hours ago, wallfish said:

Yeah, if it's all covered under warranty. Otherwise that rule is just screwing the customers over!

 

1) You'd be surprised how small the difference in overhaul vs replace is anymore once the increased cost of labor is figured in.

 

2) There are a lot of power train assemblies that are only serviced at a unit anymore (EX: 5.0 Coyotes burn oil because of faulty valve seals. Valve seals are only available with a head, so it needs two heads. It often gets low enough to damage cylinder walls because nobody checks their oil anymore, so now it need a short block too. Short block is discontinued, so now it needs a unit. How did I screw the customer over here? Someone did, but it wasn't me.).

 

3) Nobody is fixing these things unless there is a warranty anymore. Nobody has the money to pay $10K for an engine, plus another $5100 in labor to install it. That's $15K dollars to repair a $20K truck. You are gonna go buy a different truck unless someone else foots that bill.

[ri702bill 10,026]

Experience has taught me that the replacement parts are usually only as good as the parts they replace.....