Mercruiser 4.3 Alpha starting problems

[KevinKnuth]

I only use my boat on the weekends. This season we have had a lot of rain here in Northern Indiana.

Last week I uncovered my boat (a 2003 Bayliner with a 4.3 Mercruiser Alpha) and it had a good amount of water in it. (My boat does not have an automatic bilge). So I started the motor and turned on the bilge pump. No problem.

A few hours later I go to take some friends out and it wont start. In fact, it makes a grinding noise. I tried several times and same results each time. After about an hour I had a thought that it just didn't have quite enough battery, so I put my jumper pack on it and the boat still made the noise, but started! We took our ride and the boat ran fine.

This week I went down thinking I was going to have to pull the starter. However, I put the key in and and it started up (a little tough to start, took a long crank) but no noise. I did get a lot of backfire this time though. We took the boat out and had no power- it was not running well. Later in the day, back to making a grinding noise. I took a chance and changed the coil and the next day I did not have any backfire. It started up no problem.

Question- what the heck is making that grinding noise?

I have a few videos to post that may give you some clues- here is the first start from this weekend:
https://www.youtube.com/watch?v=cJAeCKqtyNg

 

[KevinKnuth]

Re: Mercruiser 4.3 Alpha starting problems

You can barely hear the grinding noise as I turn it over in this one- https://www.youtube.com/watch?v=cs5lv5jEquo

And here is a new noise from this weekend-https://www.youtube.com/watch?v=xINTqinJyg8 The engine was pretty cold here and later it did not do this

 

[r.j.dawg]

Re: Mercruiser 4.3 Alpha starting problems

You mentioned a "good amount of water". Did it make it's way to the starter?

 

[Bt Doctur]

Re: Mercruiser 4.3 Alpha starting problems

the starter was underwater, thats sounds like the bendix grinding away.did you check the engine oil ? If it made it to the driveshaft ,you have/had water in the bellows and the U joints and gimbal may be headed south too.
how does one leave a boat in the water with no automatic switch. On a lake that should be a criminal offense .gas and oil contamination from a sinking.

 

[KevinKnuth]

Re: Mercruiser 4.3 Alpha starting problems

the starter was underwater, thats sounds like the bendix grinding away.did you check the engine oil ? If it made it to the driveshaft ,you have/had water in the bellows and the U joints and gimbal may be headed south too.
how does one leave a boat in the water with no automatic switch. On a lake that should be a criminal offense .gas and oil contamination from a sinking.

When I got the boat it did not have automatic switch. Yes, there was water, but after looking where the starter actually sits, I would say it was NOT underwater. This is a bit hard to explain, but follow me if you can- the engine sits in a "pit" in the back of the boat. There are raised platforms on both sides of the engine- the water was NOT above the platforms- and that should have kept the starter out of the water too. Though, in fairness, it was pretty close so I could be wrong on that.

I did check engine oil, it looks good.

What I really cannot understand is why the problem is not constant.