2005 yamaha 8hp dies after 5 mins on lake

[Shambizzler]

My 8hp motor on my duck boat has been tempermentral lately. It was running fine, and starting on the first pull on shore, but as soon as we start motor across the lake, it will run for 3-5 minutes and die out. We put In all new fuel, and and cleaned out the cooling stream hole and it was working fine on land. As soon as we start across the lake it dies out. The last time I was able to keep it alive by working the choke. It finally died and we were not able to get it restarted. PLEASE HELP! WHAT MAY THIS BE?

[99yam40]

Make sure your fuel pump is doing its job and delivering the fuel to carb bowl

If that is OK then sounds like you need to clean fuel system.
Tank, lines, and carb

[Shambizzler]

I just out a brand new gas tank and hose on and looked at and cleaned the fuel filter...any other ideas...?

[Shambizzler]

One thing I will add, if it helps the diagnosis, when we let it cool down and rest, and we clean out the water exhaust hole, the motor will start fine on either the first or second pull, as well as idle and rev up for as long as we want, however the problem continues to arise after just a few minutes when we are out on the water moving at speed. the other day, I was able to keep it alive for an extra minute by working the choke. then it died out again until a full cool down/ resting period.

[robert graham]

It sounds like a possible fuel tank venting issue....have you checked to be sure your tank is venting?....

[Shambizzler]

I thoroghly cleaned the entire fuel system(new tank, lines, and cleaned carb) as well as checked the venting on the brand new tank...everything is good. I was able to get it going and keep it going with the aid of starting fluid, but as soon as it burns off, it dies....seems like a fuel issue, but where do I look now?