New pair of 5.7 engines eating fuel pumps

[Helibob1966]

Helped a friend drop in two fresh reman engines on his Four Winns cruiser. Installed two new mechanical pumps, break in cam on both engines no problem.
Launch boat and left engine dies idling to slip, troubleshoot and find broken pump arm. Find a Carter made in USA and install, fired right up. Run both engines in slip and right engine dies. Same issue, broken arm. Install new Airtex pump, all seems happy and take it out for the weekend no problems. Fast fwd two weeks, take it out and left engine dies, same problem. Run right engine in the slip and it dies too. Another shot pump. This is driving us nuts, previous engines had zero fuel pump problems, new engines are marine remans. Fuel pump cam lobe and actuating rods are in good condition. Anyone ever had this problem and have any insight? Should we just cut our losses and go electric. Single or dual?

 

[Scott Danforth]

something is not right to break a fuel pump arm much less multiples

both Carter and Airtex have a warranty on the pump

did you replace the fuel actuating rod?

two things that can cause a failure - too long an actuating rod, too thin a mounting plate.

another thing to check, if too long an accessory bolt is used, it will bind the fuel pump rod

you are using gaskets between the block and mounting plate, mounting plate to spacer and the spacer to pump and not a thin layer of RTV, correct? the gaskets are part of the stack height

 

[Bondo]

you are using gaskets between the block and mounting plate, mounting plate to spacer and the spacer to pump and not a thin layer of RTV, correct? the gaskets are part of the stack height

Ayuh,..... My 1st guess is the spacers got lost,...

 

[Helibob1966]

something is not right to break a fuel pump arm much less multiples

both Carter and Airtex have a warranty on the pump

did you replace the fuel actuating rod?

two things that can cause a failure - too long an actuating rod, too thin a mounting plate.

another thing to check, if too long an accessory bolt is used, it will bind the fuel pump rod

you are using gaskets between the block and mounting plate, mounting plate to spacer and the spacer to pump and not a thin layer of RTV, correct? the gaskets are part of the stack height

Been doing engine builds for 30 years and have never run into this problem. My boat has the same engine fitted with a new Carter and zero issues. Fel-pro gaskets and zero sealant. Pump rods were used on previous engines and pumps, no issues. Very baffling.

 

[Helibob1966]

We have settled on installing electric pumps. End of problem!!!

 

[Scott Danforth]

make sure you wire them with an oil pressure switch