Stalling while trolling.

[steelbreeze]

I have a '95 FourWinns 245 Sundowner with 351 Ford Volvo Penta EFI engine. This is our 6th year with it and recently stalls/soft backfiring during trolling speed. Runs great wide open and while idling. I've replaced the cap and rotor, plugs and plug wires. I've replaced in line fuel filter and the water separator. I've put 2 cans of Sea Foam in. I did reset gap on NGK plugs from factory setting of .035 to OEM setting .045, if it's relevant. It does not stall all of the time while trolling, it's hit or miss. Today though while docking it was a bit difficult. Suggestions please, thanks.

 

[bigbrownbuku]

MEFI 3 spark isnt controlled by the ecu below 1500 RPM?, check your spark with a timing light, point it at something shiny and watch it, as well as see what your timing is doing. 400 sounds like a stall the ecu is trying to control with fuel and iac. You can better see what your injectors are doing with the timing light strobe also. I have changed many pickups in those distributors.