Put a bps carb kit on my 23 vanguard. Replaced the fuel line, fuel pump, and tank. Now when I run wide open the engine will die after about 20 seconds unless I continuesly pump the fuel bulb. Running at 3/4 throttle and it runs no problem. HELP ME!!!!! Jet issue????

It doesn't sound like a jet issue. Sounds like the fuel supply isn't keeping up. The factory smallblock pumps are pretty cheezy. 1/4 inch fuel line with no air leaks and tank close to engine is your best chance for the factory pump to keep up. The easy fix here is to add an electric lift pump. Oreillys has an eldebrock 2.5-3.5 psi pump that works well

Pulled the fuel line off of the carb from the fuel pump. Turned the motor on and gave it some throttle and no fuel came out of the hose. Suction issue?

Put eyes on the tank fittings and hose. Exspecially if you have the grey EPA approved line with a liner. The liners love to collapse. Then buy a couple of factory fuel pumps. The smallblock ones are very cheap. Start with a fresh pump. Always keep a spare pump.

I re read your first post, lol. Do u have your old pump to try?

Swapped out the grey fuel line with just your standard black rubber hose. Also put the old fuel pump back on. Disconnected the fuel line from the carb and spun the motor over. I got a huge improvement on fuel flow coming out of the black hose. Hopefully it’s fixed. I still have to test it on the water under a load. Thanks for your help guys.

Nope. Still broken. The only thing we can guess is the stock pulse fuel pump can’t keep up with the minimum carb demand. Any truth to this?

I have the same motor and same parts from BPS. Having the exact same problem as you. I replaced the fuel filters, fuel line, shortened the fuel line, and the fitting to the tank. That didn’t help. Next step is a electric pump. I called Backwater Performance Systems and the guy I talked to made it seem like they’ve never heard of there being a fuel supply issue with the mikuni and the 23 Vanguard. I find that hard to believe.
Did you end up getting yours sorted out?

Aksmj- nope. Just dealt with it through duck season constantly squeezing the fuel line bulb. Once I get back from Afghanistan I’ll be adding an electric fuel pump. Edelbrock makes one that will work fine.

I've never had an issue with the stock pumps that couldn't be fixed by finding the air leak and I've run every carb from the stocker to an S&S Super E on my motor.

The stock pumps are fine on the 35. On the 23, they leave something to be desired when spinning faster than 3600. The Facet posi flow (formerly the cube) is a very reliable and long lasting option, not stupid expensive.

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