Mariner 50hp quits when cover (cowling) is on !!

[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.<br /><br />help! mandad

 

[KCLOST]

Re: Mariner 50hp quits when cover (cowling) is on !!

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]

Re: Mariner 50hp quits when cover (cowling) is on !!

Like K said it could be an exaust leak.

 

[DHPMARINE]

Re: Mariner 50hp quits when cover (cowling) is on !!

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

 

[mandad]

Re: Mariner 50hp quits when cover (cowling) is on !!

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.<br /><br />thanks for the input so far / mandad

 

[tmcalavy]

Re: Mariner 50hp quits when cover (cowling) is on !!

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

 

[Rex]

Re: Mariner 50hp quits when cover (cowling) is on !!

About a year ago some guy had the same problem<br />ask trent or red sky about this.