5.0 MPI Starting Issues

[crdpoker]

Hey guys, my 2002 5.0 MPI w/ a Bravo 3 has been great for the last year, but recently developed a starting problem. 11 second video below, but it cranks great (dual switched batteries, both fresh) and with good speed, but doesn't start as fast as it used to, and after a second or two, the starter cuts out and "bumps." It's like you disconnected the battery for 1/2 a second and then put it back. Once it starts, it seems to run fine and doesn't have a problem restarting unless you let it sit for a week and it's cold again. Anyone have any idea what this could be? I was thinking it was the starter, but it almost seems computer related, again, like the power is being completely shut off randomly during starting.
https://youtu.be/YePowvuIaUQ

Motor Specs:
2002 Mercruiser 5.0 MP w/ Bravo 3 drive (in a Monterey 228 SS)
385 total hours
Engine Serial Number: 0M347490

Thanks!

Chris

 

[Bondo]

Anyone have any idea what this could be?

Ayuh,..... Pull the spark plugs, 'n check for a cylinder with water in it,....

 

[crdpoker]

Thanks Bondo - like hydrolock? While it's sitting, water is leaking into one of the cylinders? Forgot to mention, I just changed the oil and though it was black after 100 hours, it had zero signs of any water in it.

 

[alldodge]

I'm thinking timing is incorrect/misfire, or fuel pressure

I would start by replacing the distributor cap, they are know to have issues. If it doesn't fix the issue, its good to have one on hand in case it goes out without warning.

Look closely at the plug wires for cracking

Check fuel pressure

Then check for codes

 

[scoflaw]

Battery wires or connections. Starter itself

 

[QBhoy]

Sure sounds like water in there and Hydraulic lock.

 

[SkiGuy1980]

I'd double check the grounds... and your cables can become resistive over time.