can anyone help me? i have 2 johnson seahorse 3hp model jw16 and have rebuilt carbs. the motors will start and run but will not continue to hold it's own(wont keep running) do i have the carbs adjusted right, 1 1/2 turns out on low idle and 2 1/2 on high idle. any different and the motor will not start.
You might wish to check:
Since the outboard engines start fine but then fail to keep running, it is unlikley that ignition issues are the problem. Slightly possible, heat could conceivably cause a microscopic flaw in a coil to expand, but only slightly possible. If they start easily, the ignition is probably fine.
Much more likely, you have a fuel interrupt issue. The engine starts and runs on the fuel from the starting process but then falters because it soon uses up that initial fuel supply.
Try checking these things: loose or cracked or "soft" fuel supply line or fitting. Next, leaking intake or carb gasket that seals poorly when the engine is warm, the heat causes the engine to expand but not the carb or manifold and thus the gasket to leak. Check to insure that your fuel tank is correct, not leaking or allowing air or fuel to migrate inappropriately. Also check your fuel filter, if there is water or something else in there, the vibration of the engine could stir that foreign matter up in such a fashion as to obstruct the fuel supply to the engine.
Last, just to be sure, drain, clean and dry the fuel tank, start with fresh, good gas and oil and see if that helps.
There should be a small metal screen (sintered) filter in the tank where the line exits it.
Are you saying the carb was or was not rebuilt? And to be rebuilt it needs to be removed and completely taken apart, then a carb kit installed and the rebuilt. As if this has not been done and as you say it only runs with the choke on, it needs to be done. A carb kit is only around $20 or so and it is a very easy job but needs to be done...