merc 350 mpi starting issue
 

New to the site, enjoy reading the topics. first time posting. I got an 04 v220 with merc 350 mpi, a couple times this year when I turn it off, it won't turn back on, sits for a little while then starts up fine. When it decides not to start nothing happens, I can hear the fuel pump prime when I turn the key but nothing else, not getting any alarms either. The temp is midrange 175 or lower. Has this happened to anyone else? I'm leaning toward it being the starter, the solenoid is attached to the starter. Any help is greatly appreciated.

If you have access to the starter, jump the contacts on the solenoid to see if it turns.... Sounds like resistance on the battery cables or the solenoid getting hot... Is it a Gear reduction PMI starter?

It's probably a bad starter solenoid. The only other thing besides a bad solenoid that will generally cause it not to actuate the starter when you turn the key is the neutral safety switch. Jiggle the throttle a bit in the neutral position with the key turned. Otherwise you can have someone turn the key while you jiggle the transmission shift linkage in neutral. This wouldn't be a result of heat though.

I don't think its a reduction starter. That makes sense though, usually will start fine after a few mintues of the hatch open, this last time was the longest it had been about 30 minutes. Eric, I thought that too about the throttle but hasn't really seemed to make a difference, just seems so random, and doesn't help when I use the lock out for throttle only. Maybe Ill try replacing the starter, it comes as a set with the solenoid and fuses.

On my 2003, there are two relays on top of the ECM. One is for the fuel pump, the other is the starter relay. I believe they are the same part #. An easy fix for $25-$30 bucks! You could try tapping, re-seating, or swapping them for diagnostic purposes!