it has dropped to around 3 PSI after running for a bit. No drivability issues. Most of my time is with the family in the boat and for short runs to the beach. I took it out with a full tank last Thursday and when I got to 5/8 tank, I started to see the PSI drop. The boat stalled leaving the restaurant dock (first time the boat has ever stalled) I restarted and Left for the short trip back the the home dock. During the trip back it stumbled when pushed past 2800 to 3000 RPM. I was just on plane trying to not ask too much of it. 3 PSI at that time.

i have an autometer electric fuel gauge. (With the correct 130 dollar transducer) my first step was to remove the transducer and install a non liquid filled mech gauge at the carb.

I’m leaning toward this being a fluid dynamics issue. My thought is that lifting the fuel up 6” above the tank siphon tube with a mechanical pump is at the threshold when the tank is full and as the fuel level drops, the vacuum from the mechanical pump isn’t strong enough to pull the fuel through.

still waiting for a call back from Baker fuel pumps for their input.

when I brought the boat home and installed the mech gauge, I couldn’t get good pressure. Thinking I had a tank siphon tube issue, I put a section of -10 on the filter inlet (usually fed directly from the tank) and put the free end in a can of gas. Instant fuel pressure. The gas can was 2’ above the filter.

I have a Airtex mechanical fuel pump on the water pump housing and my filter is probably 8"-10" above the tank with a NAPA 3352 10 micron filter/separator on the suction side. I have no problems with fuel pressure unless I'm idling at 600rpm. How old is the fuel pump? Vane pumps do wear out and suction is harder on them then pressure.

Baker pump with around 40 hours on it.

Exactly. Most boats, the filter/separator is atleast 6” above top of tank. And all Mercruisers are before the mechanical pump, and higher than them.

Thanks for all the question answering chromemoly.

I’ve never used a Baker pump, so I don’t know if they have a typical issue or not. I do question why the use of a high pressure pump in this app. ?

Oh wait, brain actually did something.

Did you have to clock the pump, snd if hou fid, did you know there is a specific procedure for doing so on mech pumps ? Not just unscrewing base, reorientation, then screwing back down ?

the 15 PSI pump
was used with a bypass regulator to avoid dead heading the system. This was recommended by Dale Cubic.

I didn’t clock the pump, but when I disassembled it to check for any issues, it appeared to be straight forward.

Some hsve mistaken me with him a few times. CFM :)
Great carb builder he is. :thumbs:

I have a call into him as well.
he’s a good guy!