I do have a pulse from my crank case but it goes to my external fuel pump above the engine.... Then it goes through that and returns back to my carb into the pulse sport on the carb....where could I find a carb or the plate I need?
Thanks for your help and working this out
I think that's a super BN-40mm, not absolutely sure so you should verify this. It also has an accelerator pump on it, so there's one clue as to what it should have if it's complete.
I was thinking you could pick one up on ebay fairly cheap that came off a parted ski, may or not have the same jets but if it came from a 717 I'd assume it would. Sometimes the calibration could be different depending on the air box induction system, more air means more fuel but in general it should be the same. Verify it's set up correctly before installing it, of course. Meanwhile, you're only interested in the side plate so that's a quick swap. I bet you find the whole carb used on ebay for what you'd pay for the side plate new.
So, confirm the carb you need then search for it on ebay, maybe someone here has one, like minnetonka.
The pulse line from your crank case is connected to the pulse connection of the fuel pump body, this pulse pushes and pulls the internal diaphragm back and forth to move the fuel through the two internal check valves. The fuel is pulled through the inlet check valve as the diaphragm receives a negative pressure and then the fuel is pushed out of the outlet check valve as the diaphragm receives a positive pressure. The pulse signal is on the dry side of the fuel pump diaphragm and the two check valves are on the wet side where the fuel is pumped.
So, the fuel pump can't contribute anything if it doesn't receive the pulse action from the crankcase pulse line. You should have a pulse line that goes from the crankcase barb connector to the dry side of the fuel pump diaphragm for the respective carb. If the diaphragm receives the alternating pulse and the check valves are good(not leaking backwards), the pump should move the fuel to the carb.
The nice thing I like about having the pump on the carb is, most carb kits come with the diaphragm and valve parts to rebuild the pump, not sure though how your kits come but I'd want both sides the same too. If your external pumps are rebuildable, it's possible they use the same parts as the carb-mounted pump, I'm not sure, but if they did, that would be handy for you.
So if you're considering searching for a used carb, find out which one you need(Mikuni model number spec'd for your motor) and see if there's a ski that uses the same one (a 717 ski, there's tons of them in boneyards) that someone is selling the carb off of. Heck, you could even find another carb that has the fuel pump mounted on it's side and go that route, switching to on-carb pumps instead if externals. One way may have an advantage over the other in terms of cost to rebuild, so you may have options to consider.
