Starving of gas/Start problem

[trevorprice]

This weekend I had major problems getting my 7.5 hp Merc tiller started. I checked the basics spark, etc. and then determined I wasn't getting fuel. The ball seemed hard so I really gave it some good pumps to prime it up. After about 30 minutes by the boat dock, it fired up but then died immediately. I then got it running again, and had to continuously pump the ball to keep it running, after a bit it was fine and ran great until I shut it down for a while, then same thing. I have the vent closed on the tank which may be part of the problem, I am new to the game. Can anyone tell me more about the vent and when it should be closed/open. Or maybe I need a new primer ball as well... any help would be appreciated.

 

[roscoe]

Re: Starving of gas/Start problem

Vent should be open while in use, to allow air in to replace the gas that is being sucked out by the fuel pump.<br /><br />Vent should be closed when in storage or transport to prevent spillage.<br /><br />Over pumping the bulb may cause the fuel pump diaphram to rupture, replace ment is about $10. Over pumping could also cause the gas line/carb to leak gas inside the engine compartment.<br /><br />The fuel pump operates on pressure pulses from the engine, so if you have a low compression condition, the fuel pump won't work.<br /><br />So, open the vent. I f problems persist, do a compression check with a guage. If compression is good, then disassemble the carb and give it a thorough cleaning and new gaskets.<br /><br />fuel, spark, and compression equals a running engine.