Re: 4.3L LX Choke Problem
Hi Bugup,<br /><br />As Bondo alluded, I have seen this thread and yes, I'm a 'fan' of these carbs. It sounds like you have a very typical Weber carb. <br /><br />Here's what's actually happening with your engine. <br /><br />When you shutdown these engines, the carb continues to dribble fuel through the auxillary venturiis in the primary throats. This continues until there is not enough fuel in the float chambers to sustain the syphoning effect. There is still a little fuel left in the chambers and accelerator pump plunger, enough for the next time you start it. It will run on that remaining fuel for about 30 seconds and then stall due to a
lack of fuel, not a rich condition. For reasons which I haven't fathomed (yet) the fuel seems to drain out of the fuel line as well. This is why it takes so long to restart, you're pulling fuel all the way from the tank to get to the carb. The fuel pump is wired so it will have power while cranking (through the starter motor circuit) so fuel will be pumped while cranking. <br /><br />That all said, there are a few things you can do to help the situation. As yet I haven't found a way to alleviate the problem completely (short of installing an EFI engine
)<br /><br />1. Fit an outboard fuel primer bulb in the line between the tank and the fuel pump. As soons as the engine starts, pump the bulb. You can't do it without the pump running, the internals of the pump don't allow fuel to pass unless its running.<br />2. (
THIS IS NOT RECOMMENDED) but is done by a few. (Hello Bondo
) Remove the wires on the oil pressure switch that stop the pump running when the oil pressure drops and join them together. This will have the pump running as soon as the key is turned to ON and (hopefully) start the fuel flowing up to the carb. Repeat -
THIS IS NOT RECOMMENDED.<br /><br />If you do both of these and just remember to pump the fuel up first thing in the morning, you'll have the same 'solution' that I use. <br /><br />You idle speed should be set witht he enigne in forward gear and NOT restricted, that is, Not tied to the jetty or anything, just out in the water, at idle, in gear, drifting along. Set the idle speed to about 650 RPM +/- 50.<br /><br />If you have the 9600 carb, then it has a 'heat stove' auto choke. The 9666S has the electric auto choke. The heat stove is a small (1 inch square) box bolted to the inlet manifold with a lever going up to the choke plate. The electric has a round black part bolted to the side of the carb that operates the choke plate directly. (see pictures below)<br /><br />I have one last question for you. When you are out fishing/boating and you shut the engine off and then go to restart it after more than about 10 minutes, does it take a heap of cranking to re-start, about 20-30 seconds? If it does, this is because the carb has flooded the engine. Next time you're out, sit at the back of the boat and have someone else start it, I bet you see a bit of black smoke or smell a 'rich' condition. Let me know what you find. Thanks.<br /><br />Chris..............<br /><br /><br />Picture of 9600 carb. Auto-choke is items#28-32.<br /><br />
<br /><br />Picture of 9666S carb. Auto-choke is items #11, 12.<br /><br />
