440 Engine running pump gas.Should I be running high test in this motor.

Starts fine when cold first pull but just noticed after pulling it in the garage at my dads.I let it warm up outside(rain the night before).Drove it around garage then into garage, stopped and it wanted to die so I throttled a bit but would not keep running at and idle.Shut it off and drove home.That was 2 weeks ago.When I go back up to arrys Bay this weekend and it still does it...what should I check for.
Could it have gotten wet??? But if it got wet then it would not have started right?yes or no? Thanks for what you all think.

Corby7

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thanks for responses

I had kinda similar issue with my 583 mxZ when I first got it, and it was caused by leaky crank seal. I'm not 100% sure since it's what the dealer told me as it was repair under warrany, but make sense

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