I recently bougt a small 14' boat with a 1996 Yamaha 30 ESRU 2-stroke motor. It was running a bit rough at idle, spitting and stalling and fuel could be seen in the water at idle. At speed she ran good.
I dissambled the carburetors, cleaned them in an ultrasonic washing macine so they are absoletely clean. Installed a repair kit and since the idle needles were quite worn at the middle and lower carb I replaced them as well. To be perfectly sure everything was in order i also replaced the low speed fuel jets although they looked OK. The low speed air jets cannot be bougt as spare but they looks perfect.
The carbs have been synced and adjusted according to the repair manual. I have installed new gaskets and diaphragm in the fuel pump, new thermostat, new sparkplugs and checked compression - 135 on all three cylinders.
The engine now runs perfect, normal 2-stroke smoke. I can idle for half an hour and then just slam the throttle lever to the bottom and she responds immediately without any hesitation all the way to WOT at 5400 rpm - But still sometimes gas in the water at idle.
The engine is a short shaft and the boat has a rather deep Vee for this size of boat so the engine sits low on the transom. I have now noticed that fuel in the water only shows up when the exhaust relief ports becomes submerged, as long as they are above the water - No gas in the water.
Is there any guidelines for the engine height and should the ports always be above water? Or is my symptoms indications of something else not beeing right with my engine?
I dissambled the carburetors, cleaned them in an ultrasonic washing macine so they are absoletely clean. Installed a repair kit and since the idle needles were quite worn at the middle and lower carb I replaced them as well. To be perfectly sure everything was in order i also replaced the low speed fuel jets although they looked OK. The low speed air jets cannot be bougt as spare but they looks perfect.
The carbs have been synced and adjusted according to the repair manual. I have installed new gaskets and diaphragm in the fuel pump, new thermostat, new sparkplugs and checked compression - 135 on all three cylinders.
The engine now runs perfect, normal 2-stroke smoke. I can idle for half an hour and then just slam the throttle lever to the bottom and she responds immediately without any hesitation all the way to WOT at 5400 rpm - But still sometimes gas in the water at idle.
The engine is a short shaft and the boat has a rather deep Vee for this size of boat so the engine sits low on the transom. I have now noticed that fuel in the water only shows up when the exhaust relief ports becomes submerged, as long as they are above the water - No gas in the water.
Is there any guidelines for the engine height and should the ports always be above water? Or is my symptoms indications of something else not beeing right with my engine?
