30 hp yamaha w/ 50 tohatsu carbs not pulling fuel

Guys I've got a 30 hp yamaha 3 cyl that I have put 50 hp tohatsu carbs on and it is not pulling fulling into the carbs and is running out of gas unless I pump the priming bulb on the fuel line. The reed stops have been reshaped and 40 reed blocks have been installed. The reed plate has been modifed to match the venture of the carbs as well.

This fuel lines and connections are good. I put new diaphrams, gasket, and fuel pump body on the carbs, and even made new gaskets for the carbs to make sure they were sealing against the intake plate. I still will not pull fuel into the carbs.

Any ideas and any help would be greatly appreciated so that I can fix this problem.

Quote:

---

Originally Posted by BRzuki

Guys I've got a 30 hp yamaha 3 cyl that I have put 50 hp tohatsu carbs on and it is not pulling fulling into the carbs and is running out of gas unless I pump the priming bulb on the fuel line. The reed stops have been reshaped and 40 reed blocks have been installed. The reed plate has been modifed to match the venture of the carbs as well.

This fuel lines and connections are good. I put new diaphrams, gasket, and fuel pump body on the carbs, and even made new gaskets for the carbs to make sure they were sealing against the intake plate. I still will not pull fuel into the carbs.

Any ideas and any help would be greatly appreciated so that I can fix this problem.

---

Are the carbs bigger in venturi size than the old ones? could it be if they are that not enough vacuum is being produced to move the pump diaphrams? Or maybe theres some obstruction, restriction or air leak. Look for the easy stuff 1st, Good Luck

work for me change to smaller jet

fuel is not pulled in to the carb bowl, it's pumped. hold your hand over number one carb, spin the motor with the starter, ( pull or electric ) the carb should flood, if not test out the fuel pump. ( test the pump by, bottle with gas in it on the "in line" of the pump, empty bottle on the "to the carbs line" of the pump, connect fuel line with bulb to the carbs,( grab it were the "to the carbs line" came off fill the bowls, fire her up. the fuel on the "in line" should transfur to the "to the carbs bottle.) let me know if you get what i'm sayin.:cool:

FF, I follow you on it....if fuel is not pumped to the empty bottle what steps do I need to take to rectify the problem?

gots to pull the pump, check to see if there is Pulse for the pump, (spin over motor, feel for the push and pull pulse for the pump at it's bace.) if that checks out it's in the pump.:cool::cool:

this is what most racer dont understand, should be not a problem