Hi, Why can you use a 2 stoke carb like a walbro or var jet type WXY? on a 4 stroke with the pump diaphragm installed BUT no impulse input?? It WORKS of course but seems both engines produce suction through their fuel/air ports BUT the 2 stroke wont work if you blank off the pulse port. I can only guess that the 4 stoke produces strong input suction? and this draws up on the main jet producing a vac inside the carb and the little pump valves then draw fuel through? So whats special about inlet valve suction on a 4 stoke compared to the 2 stroke suction? why doesant that do same effect or is it timing or volume and thus needs a extra pulse port? I only seen this on a Var jet so will it only work with this type as it has a long plastic tube and cut to let the fuel out and this provides a strong suction down into the carb but needs the impulse port hole built in for 2 strokes? The Var jet that came with the 4 stoke does NOT have a port hole and of course neither does the inlet port for the 4 stroke inlet either. For a test, I also grabbed another Var jet 2 stroke with a carb pulse hole and put it on the 4 stroke manifold which blanks off that pulse hole and it still worked! so that 4 stroke inlet suction is diff from 2 stroke inlet suction somehow?
Hi, Why can you use a 2 stoke carb like a walbro or var jet type WXY? on a 4 stroke with the pump diaphragm installed BUT no impulse input?? It WORKS of course but seems both engines produce suction through their fuel/air ports BUT the 2 stroke wont work if you blank off the pulse port. I can only guess that the 4 stoke produces strong input suction? and this draws up on the main jet producing a vac inside the carb and the little pump valves then draw fuel through? So whats special about inlet valve suction on a 4 stoke compared to the 2 stroke suction? why doesant that do same effect or is it timing or volume and thus needs a extra pulse port? I only seen this on a Var jet so will it only work with this type as it has a long plastic tube and cut to let the fuel out and this provides a strong suction down into the carb but needs the impulse port hole built in for 2 strokes? The Var jet that came with the 4 stoke does NOT have a port hole and of course neither does the inlet port for the 4 stroke inlet either. For a test, I also grabbed another Var jet 2 stroke with a carb pulse hole and put it on the 4 stroke manifold which blanks off that pulse hole and it still worked! so that 4 stroke inlet suction is diff from 2 stroke inlet suction somehow?