Thunderbolt 500 fuel

[Duggerar]

My motor has no fuel pump. Built into the carbs? Every thing I see shows a fuel pump.
So... I'm assuming it is a vacuum diaphragm in the carbs? I've had them rebuilt, replaced all lines and connections. All the regular stuff, new bulb, new tank, everything in proper alignment but still will not pull fuel. Suggestions? I am at a loss.

 

[jimmbo]

Being that the 500 was in production from 1961 thru 78, after which it became the 50hp, there were many refinements/changes to the motor, so a Serial # is needed

 

[Duggerar]

It's a 78 model. SN# 5111559

 

[jimmbo]

Here's the carb parts diagram for a 78 500
http://ww2.iboats.com/Carburetor-As...604709--session_id.728018870--view_id.1703224

 

[Duggerar]

I don't need parts. I need a solution to a problem. Knowledge. Experience.Somebody else who has seen this issue.

Thank you.

 

[GA_Boater]

Does the bulb get firm?

 

[jimmbo]

You asked if the fuel pump was part of the carb, the rest of my reply, regarding troubleshooting, is now in the trash can

 

[Duggerar]

Yes, the bulb gets firm

 

[GA_Boater]

Does the motor attempt to start, any pops?

How was it running before the carb and fuel hose work?