GV150 HR21 honda 1978 mower shuts down - HELP!!

[Greggbegood]

I have a GV150 HR21 Honda 1978 that was my deceased father in laws that my son and I would love to resurrect. It runs great.....for five minutes! After five minutes or so, it just stops. I was lead to believe it might be the CDI ignition coil. They are hard to find, but we finally did find one. Although also from a GV150 HR21 mower, on the spark plug cord it said "-1" as opposed to the original one that said "+2." (Could someone explain this to me?). Regardless, when I put the new used one on, no help, same problem. Runs great for five minutes, then it stops running. If I go out 10 minutes later, ya baby, it starts and runs....you guessed it, for five minutes. So something must be overheating, then shutting down, then after cooling, it can run again.

So HELP! We wanna make grandpa in heaven proud. What is our problem?

Thanks. Gregg

 

[mechanic mark]

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[bertsmobile1]

Spend a few $ and buy an inline a neon tube or led ignition tester.
Pop it on the spark plug lead start the mower and watch it.
If it continuse to flash as the engine slows down to a stop then you ignition coil & switch is fine.
This is my most used tool, I probably loose about 1/2 dozen of these every year and keep 1 in the service van, 1 in the tool box & 2 in the workshop. Saves me thousands of hours every year.
If you are into useful gadgets then buy a color tune and install that into the motor, start it then sit down & watch he color tune and see which way the colours go just before the engine dies.
Yellow = flooding , blueish white = no fuel.
Another indespenciable tool in my shop again I have 3.

And before you do anything go and get some nice new premium grade fuel. drain both the tank & carb and refill with nice new fuel.
Could be some thing as simple as water in the float bowl.

Finally check the oil level.
Honda fit oil switches to a lot of their domestic engines so a low oil situation might do the same, while all the oil is in the sump it is happy, once the motor starts throwing oil every where the sump level drops jut low enough to activater the cut out switch.