AirSniper
Active Member
Passing on some good information, hope this helps someone sometime.
During a start & stop fishing day, all of a sudden the engine wouldn't start. Cranked, no start. Checked lanyard, good (no beep when switching to on with lanyard pulled).
noticed that the normal start sequence was off; usually switching to run, get the beep, then there is an electric fule pump that comes on for a few seconds. When that stops, the tach guage "blips". There was no pump & no blip. Ran the battery out trying to start, tapped a few components, no joy.
Took home and troubleshot. Fuses good (all that i found). No voltage to the lift pump when turned on. Finally found the relay on the starboard side, buried next to the engine. One terminal showed overheating & the connector pin as well. The relay clicked going to run position, but no pump. re-seated the relay a few times, and finally while tapping it as my wife switched to run, the lifter pump came to life.
Did this a few times - it only worked intermittently - to get the pump to send enough fuel to the separator, and got the engine to start.
Since the connector is a little crispy too, i ordered similar (maybe not the same) relays with connectors online. About $8 each. If the relay fits,I'll try it and have another relay with connector ready to replace if it fails again.
Tech info available for the Merc Opti's is awful. There were a few posts here that helped, but I didn't find concise info. Hope this thread is helpful, i'm going to put in a few searchable keywords below). BTW, these relays seem common, apparently same part number as the outboard trim relays. The OEM par number is Quicksilver - Mercruiser 882751, 710-882751.
electric fuel pump
main power relay
MPR
lift pump
trim relay
During a start & stop fishing day, all of a sudden the engine wouldn't start. Cranked, no start. Checked lanyard, good (no beep when switching to on with lanyard pulled).
noticed that the normal start sequence was off; usually switching to run, get the beep, then there is an electric fule pump that comes on for a few seconds. When that stops, the tach guage "blips". There was no pump & no blip. Ran the battery out trying to start, tapped a few components, no joy.
Took home and troubleshot. Fuses good (all that i found). No voltage to the lift pump when turned on. Finally found the relay on the starboard side, buried next to the engine. One terminal showed overheating & the connector pin as well. The relay clicked going to run position, but no pump. re-seated the relay a few times, and finally while tapping it as my wife switched to run, the lifter pump came to life.
Did this a few times - it only worked intermittently - to get the pump to send enough fuel to the separator, and got the engine to start.
Since the connector is a little crispy too, i ordered similar (maybe not the same) relays with connectors online. About $8 each. If the relay fits,I'll try it and have another relay with connector ready to replace if it fails again.
Tech info available for the Merc Opti's is awful. There were a few posts here that helped, but I didn't find concise info. Hope this thread is helpful, i'm going to put in a few searchable keywords below). BTW, these relays seem common, apparently same part number as the outboard trim relays. The OEM par number is Quicksilver - Mercruiser 882751, 710-882751.
electric fuel pump
main power relay
MPR
lift pump
trim relay
