Fuel pump pressure and Flooding issues

[Sea Guardian]

I have a flooding issue that I am trying to solve. But first, specifications: 2006 Tahoe Q4 with a Mercruiser 4.3LH, 2 barrel Mercarb & Factory fuel Pump.
When I first bought this boat I replaced the TKS carb with a mercarb, Right out of the gate I had some flooding issues from WOT to idle. cleaned up the carb replaced the float, seat and the needle (removed Spring and installed solid per a tech bulletin I found). once all this was done reassembly and tune boat ran great last year, this year replaced all plugs, distributor cap and rotor, adjusted timing SAT, boat idle great on muffs and purring the way she should.
Plan to put it in the water 2 weeks later and quick run on the Muffs, wont stay running, smoking and no idle. Engine is pumping too much fuel into the carb. Quick test on the fuel pressure my gauge is reading 7 psig, just to comfort my self I bring it to my calibration lab and the gauge is off by 1.5 psig so the pump is pumping 8.5 psig.
The service manual states 3-7 psi, most of the electric pumps i see online state 8 psi.
Is my fuel pressure normal or high? have you ever seen a pump fail higher pressure? looking for some insight. Thanks

 

[Bondo]

Ayuh,..... Welcome Aboard,..... Did ya happen to tap the top of the cap near the needle seat, just in case it stuck open,..??

I prefer 4 to 6 psi, but 4 to 8 psi could work I spose,...

You've got the mechanical pump, right,..??
Put a thick gasket or spacer block 'tween it, 'n the block to shorten the stroke,....

 

[Rick Stephens]

Wouldn't have a mechanical on a 2005....

does the needle have the little spring clip holding it to the float lever? Those, if not hooked up right, can hold the needle open.

 

[Sea Guardian]

Ayuh,..... Welcome Aboard,..... Did ya happen to tap the top of the cap near the needle seat, just in case it stuck open,..??

I prefer 4 to 6 psi, but 4 to 8 psi could work I spose,...

You've got the mechanical pump, right,..??
Put a thick gasket or spacer block 'tween it, 'n the block to shorten the stroke,....

Yup, gave her a few love taps, pulled the power to the fuel pump, started her up on the fuel in the bowl and gave her some stiff bumps, reconnected the fuel pump flooded out..
Thanks for the welcome.. been a reader of the forums for a long time.

 

[Sea Guardian]

Yup, gave her a few love taps, pulled the power to the fuel pump, started her up on the fuel in the bowl and gave her some stiff bumps, reconnected the fuel pump flooded out..
Thanks for the welcome.. been a reader of the forums for a long time.

Ohh electric fuel pump..

 

[Sea Guardian]

Wouldn't have a mechanical on a 2005....

does the needle have the little spring clip holding it to the float lever? Those, if not hooked up right, can hold the needle open.

Nope, removed the spring needle and installed the solid needle. No clip flat press onto the bottom of the needle.

 

[Sea Guardian]

Some of my thoughts, feedback welcome. Thinking, cleaning and adjusting the float a 32nd or so below factory recomended setting. Might buy a newer marine Carter pump and see if that has some lower pressure.