Fuel pump cutting out, 4.3 merc

chknfrmr

Cadet
Joined
Oct 4, 2023
Messages
10
Good evening.
I have a 2003 4.3 mercruiser, carbureted engine. Three times now, my motor has suddenly died while running. It will crank over, but not fire. It seems like its out of fuel. The only way to get it to start is to jumper the fuel pump with 12 volts. Once I refill the float bowl, the boat starts, and will continue to run, no problem. The first 2 times, I was slowly cruising and thought maybe my oil pressure was too low due to prolonged running at low rpm. This evening it did it while pulling a tube, and running at 3000 rpm or slightly higher. My oil pressure was 40 psi pretty consistently at that rpm. Any thoughts?
 

chknfrmr

Cadet
Joined
Oct 4, 2023
Messages
10
Good morning.
I have a 2003 Crestliner with a 4.3 mercruiser. The motor is carbureted, not fuel injected. Three times now, my engine quit on me while driving. The first two times it happened while slowly cruising down the river, low rpm's. Yesterday it happened while pulling a tube, higher rims. After it stalls, it will crank but not fire. It seems to be out of fuel. If I jumper the fuel pump, the boat fires up again, and continues running fine for the rest of the day. I thought maybe low oil pressure from driving slow, but that wasn't the case yesterday. Oil level in the engine is good. Any thoughts?
Thanks
 

chknfrmr

Cadet
Joined
Oct 4, 2023
Messages
10
Would it fail intermittently? Once I get it running again its fine for the next several outings. Its happened once at the end of last season, once about a month ago and once yesterday.
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
44,242
Might be a bad connection, and if it is than need to start cleaning contacts

A bad connection could be anywhere from the main harness to the key switch and back to the motor
 
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