I have had to replace the emm on my etec 150 twice once in July of 2012 2nd time May of 2015. The 1st time it was under warrenty this time it is on my dollar. I would not think the emm would be a consumable part like spark plugs or water pumps. Is this a common problem?
EMM's are not a common problem. Often there are other factors that shorten the life of an EMM.
Wing nuts on the battery cables are one of the biggest offenders as they can loosen and cause intermittent connections which in turn cause voltage spikes. Those stress even the hardiest of electronic parts and that leads to breakdowns. Intermittent connections can also be caused by corrosion in the wiring or on the connectors, faulty battery switches, and loose or corroded ground wires.
In addition engine overheating or restricted cooling water flow through the EMM make its internal temperature rise above normal limits which contributes to shorter life.
Thanks for the reply Bill, the tecnician at the dealer said the emm going bad was caused by a fuel pump failure. I thought this was kind of odd. If this is true I would be better off replacing the Fuel pump every 2 years ,since I had to replace the EMM and fuel pump at a cost of $3000.00.
05-19-2015 06:43 - edited 05-19-2015 06:50
The electric fuel pump is very reliable but if any water, phase-separated ethanol, or some contaminated gasoline goes through it, the internal parts could rust and corrode internally, especially if the boat was used infrequently or during storage over the winter.
This in turn would force the pump to draw more current that it was designed for because the rust or debris would make it more difficult to for the pump's electric motor to spin the damaged pump mechanism. In extreme cases the motor would not run well at high speed due to the decreased pump output.
In theory, the excess current draw of the pump could possibly affect the 12 volt generating and regulating circuits inside the EMM over time.
My guess would be that if the bad pump was cut open, the steel rotor and housing would show signs of rust or corrosion buildup.
Thanks for the help Bill, I do not have the pump so I cannot test your theory. The boat has a 10 micron water seperator, I only use non etenol fuel and use startron fuel treatment every fill up. i do not know what else I could do to prevent this from happening.'