Pls help, outboard won't stay running

[balin206]

I have a 97 Suzuki 9.9hp 2 stroke with oil injection. Bought used and ran fine thru the first tank of gas. I can start but won't keep running. Playing with choke will help keep going at med rpm (choke full open or closed will kill engine). I am using regular unleaded and premium merc 2 stroke oil. After starting and running ok, will miss, cough and fade away. I will get a manual tomorrow to check for engine / carb settings but any advice before I start fiddling or take into a shop... Any advice, or diagnostic exercises would be appreciated. Thanks in advance.

 

[JB]

Re: Pls help, outboard won't stay running

Howdy, Balin. Fuel starvation is probably the most common complaint in outboards. The most common causes are:<br /><br />Clogged or not open(forgot?)fuel tank vent.<br />Air leak in fuel line or primer bulb.<br />Clogged pick-up in fuel tank.<br />Failing fuel pump.<br />Adjustable low speed (idle)jet set too lean.<br />Adjustable high speed jet set too lean.<br />Dirt or varnish clogging jets in carburetor.<br /><br />First check your vent, then check hoses and primer bulb for air leaks.<br /><br />Pump your primer bulb when engine tries to starve out. If this solves the problem, overhaul your fuel pump and clean carb.<br /><br />After engine has warmed up, back any jet adjustments out (CCW) half a turn. If this doesn't help, return them to original settings. Clean carb.<br /><br />Good luck.<br />Red sky at night. . .<br />JB

 

[balin206]

Re: Pls help, outboard won't stay running

Thanks JB. I will try your suggestions tonight and let you know what happens. The timely help / advice is greatly appreciated.

 

[balin206]

Re: Pls help, outboard won't stay running

Hi JB and all. Finally got back to tell my story. You can add this one to the checklist for engines that won't stay running...<br />I checked all fuel related items, and pumping the ball, but nothing seemed to help. Finally decided to inspect the plugs to see if they could provide any clues to the problem (running lean or rich) and they were not even finger tight. <br />They must have vibrated loose over the season. They still had their washers, and were relatively clean. Once tightened, the motor ran like a top. <br />I did lose a weekend of sailing over the problem, and the kids were not too happy about sitting on the boat while dad fiddled with the engine initially, but I now know alot more about my motor. <br /><br />Thanks again JB for your timely help and suggestions.