Small Engines (Lawn Mowers, etc.): Craftsman CV461S, bolt torque, holes in the head

Question
QUESTION: I have a Craftsman mower with a CV461S engine.  The fuel shut-off solenoid burnt out and I replaced it.  It starts fine and for a few minutes runs really well.  Then it starts losing power and at times surges for just a moment.  I have replaced the fuel filter, air filter and battery.  I don't have the correct manual to see any of the wiring but one red wire had a bad spot and I stripped both sides and twisted them together and used electrical tape on it.  If the connection is bad on that or on the solenoid wire will it cause a problem after a few minutes?

ANSWER: Did you solder the wires after twisting them together?  It is possible for the connection to be weak but I doubt that is the problem.  I would recommend soldering or using a butt connector to repair the damaged wire.  Why did you have to repair the wire?  Was the wire insulation wore through?

The link below will take you to the engine service manual:

http://www.kohlerengines.com/onlinecatalog/pdf/tp_2339_d.pdf

I rarely see fuel shut-off solenoids burn out.  Do you know why it burnt out?  Do you have a multimeter to check the mower electric system?

I suspect the problem is fuel related, probably a dirty carb or bad fuel pump, but I'd like some more info on the bad wire to make sure the electrical system is properly working.

Eric

---------- FOLLOW-UP ----------

QUESTION: My brother-in-law, who is a mechanic, has checked out almost everything and has not found a problem.  He is going to see if he can tell if the ignition coil is bad.  It has problems after the engine heats up for just a few minutes.

Answer
Heat can cause coils to do funny things.  I have had to replace a few coils only after I had checked all the other components; spark plug, fuel pump, carb rebuild, valve clearance, head gasket leaking, head bolt torque...

My worst problem I ever had, with symptoms like yours, was a few leaky head bolts.  Turned out the holes in the head had wore over time but would only start leaking when the engine got hot.  However, the problem appeared to be fuel related, which it was, fuel was leaking out past the head bolt, but I kept focusing on the carb.

If you brother has a cylinder leak down tester you can quickly rule out any compression or leaky head gasket problems.

Have you replaced the spark plug?  I've seen a few odd problems due to a $3 spark plug.

Let me know what you find.
Eric