fishingdan
Lieutenant Junior Grade
- Joined
- Feb 12, 2005
- Messages
- 1,045
Here is my scenario. I hope some of you folks can offer some suggestions. The engine is a 1985 mercury 50, 4 cylinder, ser number a102150. I am the original owner. <br /><br />In August 04, the carbs were professionally rebuilt and the switch box was replaced by a reputable local marina. The engine ran fine until this spring (idle was a little rougher than it had been). I thought I had fuel leaking out of the front of one of the carbs and possibly some gunk in the needle valve of the lower carb, but it turns out that the float bowl of the top carb was leaking. After further inspection, it was very loose and the gasket had slipped out. <br /><br />Earlier this week, I loosened the front cowling support and loosened the top carb from the engine. I left the fuel lines connected to the carb. Once I had the carb free from the engine block, I turned enough to access the float bowl. I removed the float bowl and the float bowl gaskets. In the process, the baffle slipped out (at least now I know what it is after looking through the service manual). I repositioned the baffle per the manual, re-seated the float bowl gasket and float bowl screw gaskets and then re-installed the float bowl. I then repositioned the carb over the linkage to the bottom carb and slid it into position. I re-installed the front cowling support, choke assembly and everything seemed to be back the way it was. <br /><br />I then started up the engine. All looked good, the engine started up and there was no more leak. I took the boat out and pulled away from the doc. Once I motored through the marina, I started to give it some gas and had no power. It seemed to run up to 40% power and then the throttle control was at the WOT stops. The engine seemed like it was running smoothly at the higher throttle positions. Today in Neutral I could barely keep it running. It seemed like it was starved for fuel. When I got back in, I took the cowling off to make sure that the throttle actuator was accessing the thing on the top carb correctly and it seems ok. <br /><br />Here are some pics of the engine with the cowling off. The picture title "Engine throttle closed" is a picture looking down at the carbs while the engine control is in neutral. The picture titled "Engine throttle open" is a pic when the throttle is pushed forward to the WOT position. The third picture is an attempt to look into the throats of the carbs and verify that they are opening in sync. They seem to be in the same position throughout the throttle control movement from neutral to WOT. Pics were taken while engine was off. <br /><br /> http://pg.photos.yahoo.com/ph/redbird1988/album?.dir=/fd78 <br /><br />I am now wondering if the engine is running without the top carb operating. I plan to loosen the float bowl screw on the top carb to make sure there is at least fuel in there. <br /><br />Although the engine had the fuel leak, it seemed to run well at WOT before I touched the top carb. <br /><br />What additional trouble shooting steps can I take? <br /><br />Thanks in advance for any help.<br /><br />Dan
