Mercruiser 5.7 MPI issue

[Randy Dive]

Hello, new to the forum here. I am hoping that you can help me with my engine issue. I have a 2000 Mercruiser 350 MPI MIE. I just replaced the engine, starter, alternator, exhaust system, tensioner pulley, sea water and circulation pumps. When I start the motor, the circ pump is not turning... the belt is slipping on the pulley. New belt, and I double checked the tension. I thought maybe the sea pump impeller got torn up, but thats fine. I had someone suggest that the rear bearing in the circ pump may have failed, so I replaced the pump (2nd new pump... not a reman). Problem persists. Any and all help is greatly appreciated, as this thing is giving me fits. Thx...

 

[muc]

Take the belt off and spin all the pulleys by hand, tell us what you feel on all of them.

 

[Randy Dive]

I did that, all of the pulleys are snug on the pumps, there is no play in any of the shafts, and the sea pump I opened and inspected yesterday. The impeller is fine. The circ pump will spin by hand, as will the sea pump, tensioner pulley, and alternator pulley. Thx...

 

[muc]

Is it possible that the belt isn’t routed right?
Maybe post a serial number and we can look for a diagram that shows how it should look.

 

[Randy Dive]

I will post a pic of the front of the motor. As I have twins though, I compared the 2 engines and the other (port) is the same and runs fine.

 

[alldodge]

Check how many grooves are in the belt, might have installed the wrong one, or wrong number of grooves on the pulley

 

[Randy Dive]

Alldodge, I installed a 6-grooved belt. I will double check later on and post my findings. Thank you