I am in process of overhauling carburetor and the whole fuel system of my OB and have a few questions about its operation. It is definitely Type IV as listed in SELOC manual and I am now waiting for a new float chamber and high speed orifice as it would not come loose without breaking.
I can well how understand how fuel enters the float chamber from the pump and is pulled to the throat through the high speed orifice, but how the low speed jet is fed? Directly by the pump? (If so, there might be something blocking the fuel supply there.)
While disassembling I found out that the fuel inlet valve was very badly worn, no other obvious problems. The OB had such a problem that every now and then it would simply not start or "promise" no matter how much cranking and then just start and run again after some time. The last time I experienced this I was able to confirm that atleast some spark was present, did not have proper tester along then, and that fuel not flow into engine. Primer became hard and fuel line pressurized. Could this problem have been caused by the inlet valve? Or blocked low speed jet more likely?
I can well how understand how fuel enters the float chamber from the pump and is pulled to the throat through the high speed orifice, but how the low speed jet is fed? Directly by the pump? (If so, there might be something blocking the fuel supply there.)
While disassembling I found out that the fuel inlet valve was very badly worn, no other obvious problems. The OB had such a problem that every now and then it would simply not start or "promise" no matter how much cranking and then just start and run again after some time. The last time I experienced this I was able to confirm that atleast some spark was present, did not have proper tester along then, and that fuel not flow into engine. Primer became hard and fuel line pressurized. Could this problem have been caused by the inlet valve? Or blocked low speed jet more likely?