Mercruiser 5.7 efi stalled, won't start
 

Hey guys, new here...fairly new to boating.
We bought a 2000 Monterey 242cr last year with a Mercruiser 5.7efi and Bravo 3 drive. We took it out last year for a total of around 30 hours without any issues and we absolutely fell in love with the lifestyle!
I am mechanically inclined so I intended to do all of the preventive maintenance myself. Took off the drive at the end of the season last year. Noticed water in the drive oil and water in the main below. The mechanic at the Merc dealer said the first thing was to change belows and take it from there. So I did. Took the boat out...40 minutes to the beach and back...no issues whatsoever. The second time we took it out, the alarm sounded off and noticed the engine was overheating. After that, I let the engine cool off and ran ot for about a minute or so to get back at the dock. Checked the water intake hose and it wasn't pinched or anything. Came back home, started the engine and it wasn't sucking up any water. Took the impeller housing apart and the impeller was all in bits and pieces. Changed the impeller and housing, changed the thermostat, changed the belt. Primed the water pump by filling the engine with water, connected the water on the drive, started the engine for a few minutes and all seemed fine. The engine was sucking inbthe water and after a few seconds, water was com8ng out of the exhaust.
So we took the boat out. I have to say that from where we put the boat in the water, to when when get the river when we can speed up, we have to go through a chanel at 5mph for about 10 minutes. Everything seemed finewith the engine. Temperature was good, and I could see on the gauge that the new thermostat was working fine. Temp went from 150 to 180, and then back down to 150. So when we got to the river and raised the rpm, and noticed the engine seemed to lack power, wasn't able to gain enough speed to get the boat out of the water, and we heard a bizarre clicking noise coming from the back. Put it back in neutral and opened the hatch to the engine to see if the clicking came from the engine itself, but it was running smoothly. I then raised the rpm...engine stumbled and died. There was like a burnt rubber smell, and I could see a little smoke coming out of the engine bay. After taking a good look around everythind, I noticed that there was oil dripping out from underneath the power stearing pump. Check the level and it was just below the"add" line, so I filled it up and knew I would have to take care of this issue. So then I tried to start it back up...it would crank but wouldn't start. I shot the batteries off, let it rest for half an hour, tried again...would crank but very slowly as if the battery died.
The simplest explanation would be a bad alternator? ...or did I damaged something when the impeller went bad? I am hesitant to jump-start the engine to check if the alternator.
Was thinking maybe the power stearing pump seized, so I took the belt off and the pulley spins freely, water impeller pulley spins with resistance(normal), the water pump pulley moves a little but won't spin....normal??

So there it is. I know it was a long post, but I tried to give you as much details as possible. Hope one of you guys can help.
Thanks

What do you mean with the drive sucking up water? Does this mean the drive was in a bucket or something?

The burnt rubber smell, did you check alignment prior to reinstalling the drive?
Did the drive slide all the way on easy or was it hard ?

Thinking you over heated and something may be damaged

Ive heard crackling before it was the rubber exhaust hose connecting the riser to the transom tip, when you smoked the impeller did you back flush the system ?

By sucking up water I meant through a hose and flusher...and yes I have to admit, when I put the drive back on, even if I used the alignment tool, the last inch or so was harder to get in. That was my first thought when I heard the clicking noise. Shaft or bearing maybe be damaged, but that shouldn't cause the engine not to start? I guess I will have to take the drive off to see if anything was damaged in there.
And yes I did back flush the engine

Drive wasn't aligned correctly so may have burned coupler up, don't know but removing drive can provide some insight

The clicking was most likely the motor was overheated. The motor turning over slowly when it didn't before is another sign it probably overheated. Bearings are probably shot. Could do a compression test but unless you can get 300 rpm from the starter, it will be non-conclusive

The recirculating water pump on engine should rotate easy by hand. Just a very slight drag. Very very slight drag.

The sea water pump with its rubber vanes pressing hard against the body will be pretty tough go turn by hand.

To confirm, which pump was very hard cor you go turn ?

I took the belt off to check the pulleys again and the water pump pulley now spins freely Not sure why...maybe the belt wasn't all the way off the pulley when I first checked, or it could be a piece of the old impeller that was stuck in the pump.
The first time we took the boat out, we had absolutely no issues. No noises, no overheat, no alarms, engine cranked and started normally. Went 40 minutes out, 40 minutes back. That's why I don't think it is a problem with the alignment. We would've heard something on that first run? I will take the drive off anyways just to make sure.
One thing I forgot to mention, and this is the reason why I thought it might be a bad alternator...when the engine lacked power on our second run, when I was trying to get the boat on plane, I noticed the drive wouldn't raise or lower.
I put a brand new "accessories" battery, and it was now dead. I always keep a second battery on board, so I switched it and was able to raise the drive.
A marine engine operates the same as a car engine!? If the alternator goes bad, the engine will still run for a few minutes before stalling? From which of the 2 batteries is the coil taking its power to spark the plugs? And are both batteries being charged by the alternator when the engine is running ?

OK

Yes and yes

Coil runs from the start battery

Hi alldodge. Thanks for trying to help. Maybe this will help you understand what is wrong. I decided to jump start the engine to see if it would start with a good battery. When I turned the key to first position...no 2 beeps and none of the gauges worked. I think the fuel gauge and volts gauge are supposed to work. I turned the key all the way for half a second just to see if it would crank, and it does. All of this has to be related somehow!
If you can think of something to help me, i'd really appreciate it. Thanks

Do you have a battery switch and know how to use it and how it works ?

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