Mower runs rough then clears up after 10 minutes

[HornetCoach]

I have a mini fastrak with 16 hp Honda engine. For the past few weeks the mower has run very rough when started. No problem starting. The exhaust sounds very loud, there is perhaps some preignition and the mower lacks power. After about 10 minutes the problem goes away and the engine runs completely normally. The change is quite sudden, in about one second is goes from tough to good. Any ideas? Thanks.

 

[The Chairman]

It sounds like water. Replace your fuel filter. Pull the carb off and clear out any crud. You might even put a 1/8th cup of alcohol in your gas tank. Alcohol is miscible with both water and fuel. That means a little alcohol with absorb the water in your tank and you'll just burn it out.

 

[HornetCoach]

It’s possible, I have had fuel problems on my boat at the same time and they were filled from the same cans. I will check.