[mandad]

I've recently purchased a Suntracker Pontoon with an 89' 50hp Mariner. I have rebuilt the carbs and replaced the rest of the fuel system. It runs great with the cover off. As soon as it is replaced I can run mabey 1 to 3 minutes at or near wot and she will stumble and finally quit. I have looked for loose ort bare wires and pinched fuel lines and come up empty handed. This one is beyond me.help! mandad

[KCLOST]

Are you sure that you don't have any exhaust leaks (manifold gaskets/powerhead gasket) that may cause a buildup of exhaust fumes inside the cowling and choke the engine?

[Elmer Fudge]

Like K said it could be an exaust leak.

[DHPMARINE]

mandad,is this a sudden problem,or one that has been going on for awhile?Try pumping the primer bulb just as it happens.If that "fixes"it,it's still most likely a fuel problem.Probably the pump.If it is a long existing problem,I'm afraid you'll find the exhaust housing blocked just below the powerhead.(carbon buildup)DHP

[mandad]

I will inspect closer tomorrow for an exhaust leak. But I have sat right beside the engine while running and have not seen heahd or smelled any leaks. Could it be a leak so small you couldn't see any smoke? The boat is new to me and has had the pboblem all along.thanks for the input so far / mandad

[tmcalavy]

She could be starving for oxygen with the cowl on. Check to make sure the vent in the cowl is free and clear.

[Rex]

About a year ago some guy had the same problemask trent or red sky about this.