Merc I/O problems... I Screwed up...

jinxkim

Recruit
Joined
Jul 30, 2007
Messages
2
Any help would be greatly appreciated... Thanx in advance.

Ok. Here's the story.

I took the boat out this weekend, launched it, loaded everyone into the boat. When i went to start it.. nothing. no juice, just click click. Damn battery is too weak to turn the engine. I asked everyone and their mother on the dock if they had a battery starter... no one did. I was getting desperate so i pulled my batttery from my car and swapped it with my boat's. Still the engine didn't start. Now here's where i messed up big time. When I went to put back my original battery, i accidently switched the positive and negative cables on the battery. All of a sudden, smoke billowed out from the engine area and the smell of burnt rubber was strong.

But in the end, someone gave me a jump start and we were off. It was running no problem for about 3-4 hours. I dared not to turn off the engine. But around the 3rd hour, the engine died on me. Luckily, the battery charged enough that i was able to restart the motor. We ran it for another hour and then it died again. That time, the battery was dead. I had to get another jump and we made it back to the dock area but the engine died again. Each time it died, it wasn't idle. I was actually driving slow.

Another thing i noticed is that if i was cruising around 30 mph, it felt as if the engine or transmission would not cruise but only for a second. Almost like gas wasn't getting to the engine for a sec but then it would return to normal.

Here are my questions:

If the battery dies while the engine is running, would that cause the engine to die? I heard somewhere that the battery is only needed to start the engine.

I know something must have fried when i swapped the battery cables but does anyone know what might have fried in the engine area? The boat did run after all the smoke. Was i lucky enough not to have to pay big bucks to repair this? Or is this the cause of my engine dying?

If the battery didn't charge after the second kill, does that mean my altenator is shot as well? I'm assuming it's the original battery so i'm leaning more towards the battery being dead.

The boat is a 1996 Mariah with a merc Alpha one 350hp I/O.

Please be gentle. it's my first boat and I know i screwed up. I bought the boat last year used.

Thank you for all your feedback!
 

DukesFin

Chief Petty Officer
Joined
Oct 12, 2005
Messages
500
Re: Merc I/O problems... I Screwed up...

Sounds like you fried your alternator, but I'm no pro...

I did the same thing! What happened to mine when I did that was I had fried the electronic ignition...

Good luck and wait for more "professional" responses.

Humility sounded good though!
 

chaparral442

Petty Officer 2nd Class
Joined
Mar 25, 2007
Messages
153
Re: Merc I/O problems... I Screwed up...

all signs point to frying the alternator- it is not abnormal even in a vehicle if the battery or alt goes out that it takes the other with it--

Pull the ALT have it checked, if bad replace with a new Battery-- that may be all you have done

We all learn through our mistakes

Welcome to owning a boat!
 

sea wolf

Lieutenant Junior Grade
Joined
Apr 3, 2002
Messages
1,219
Re: Merc I/O problems... I Screwed up...

You may be able to get that alt rebuilt at a shop that does that kind of work. Can save yourself a few bucks. And don't sweat it. We all make mistakes, that's why they make WhiteOut.....................
 

jinxkim

Recruit
Joined
Jul 30, 2007
Messages
2
Re: Merc I/O problems... I Screwed up...

If it's the alternator, why did it charge the battery after the first die? After the fiasco on the docks, I jump started the battery and ran it for 3 hours. It charged the battery during that time and I was able to restart it after the first time it died. Do you guys think the alternator just failed after that?

Thanks for the responses and support.

Also can anyone answer the first question i posted? Is the battery/alternator the cause of the engine failing while i was driving the boat?
 

sea wolf

Lieutenant Junior Grade
Joined
Apr 3, 2002
Messages
1,219
Re: Merc I/O problems... I Screwed up...

A bad alt. can cause your symptoms. Who knows why it ran for the 3 hrs? Pull it & have it tested.
 

BRG25

Chief Petty Officer
Joined
Jul 13, 2001
Messages
528
Re: Merc I/O problems... I Screwed up...

Instead of guessing if your alternator is bad, check the voltage at the battery. With boat not running it will be aound 12 volts. With the engine is running, it should be around 13.5 volts while charging. Yes, the engine could stall if the alternator and battery are both bad. Wouldn't hurt to take the battery out and have it load tested too.
 
Joined
Jun 29, 2007
Messages
58
Re: Merc I/O problems... I Screwed up...

I'd think that more than anything else at this point, you would want to make a positive ID on what burned. Might be your alternator, might be something else that could cause you future problems, probably wasn't your battery. Look for burnt insulation, traces of overheating, etc. Use your nose, follow the scent of burnt rubber if it's not too overwhelming in the engine compartment. Whatever burned should be replaced, as a minimum.
 

milkyway

Chief Petty Officer
Joined
Jul 31, 2004
Messages
535
Re: Merc I/O problems... I Screwed up...

I would replace the battery with a new one to isolate this issue. If your engine starts several times without hesitation then your starter is good. Then test your alternator using a simple tester if it's charging appropriately. If ok, take her out for a spin and see what happens. It it stalls again, check all your ignition components and come back and post your problems.
 
Joined
Jul 29, 2007
Messages
8
Re: Merc I/O problems... I Screwed up...

I am no pro and agree with other responses on the ALT.

I do know that it takes a while to get a good charge back if batt was dead/ close to dead, esp when cranking repeatedly (could explain the 2nd time). Also, check connections, esp Ground to motor, as that could look and sound like a dead battery (although volt meter would tell you if batt has juice or not). I had a loose ground one time and she would not crank...tightened the ground and she was back immediately
 

ParallaxBill

Petty Officer 1st Class
Joined
Aug 27, 2006
Messages
341
Re: Merc I/O problems... I Screwed up...

Running a motor on a dead alternator will eventually drain your battery and your motor will cease to run off the dying battery. Alternators will not let your engine run with a dead battery like some generators used to be able to do in cars and trucks.
 

crossent

Cadet
Joined
Jun 21, 2007
Messages
29
Re: Merc I/O problems... I Screwed up...

With it running, disconnect the ground cable on the battery. If it dies, your alt. is not working.
Mike
 

qystan

Petty Officer 1st Class
Joined
Apr 26, 2004
Messages
291
Re: Merc I/O problems... I Screwed up...

With it running, disconnect the ground cable on the battery. If it dies, your alt. is not working.
Mike

Never disconnect the battery when the engine is running - boat or car. The alternator will put out the max voltage it can (in the 20V region). The high voltage can fry your electronics equipment/ignition electronics/meters.
 

gone2bch

Recruit
Joined
Aug 2, 2007
Messages
3
Re: Merc I/O problems... I Screwed up...

More than likely, what smoked was the coating on your battery wires. Trace them both, the hot to the starter and the ground to the block. Then trace the wires from the alternator to see if they are damaged. If I understand this correctly, you put your dead battery back into the boat and then jumped it off. If this is the case your alternator is not bad because it would not have built the battery back up. A battery that has a bad cell can get enough juice to crank a motor when it is still hot from the alternator running, but will not store that juice to keep cranking it repeatedly. Notice I say can, because it will have a mind of its own when it decides not to work at all.
So the first thing I would do, also being the simplest, take the battery to have it checked. It was dead when you got to the lake for some reason. If it turns out that the battery was good, the alternator is only two bolts and two wire connections to remove. Make sure to disconnect the battery before you take the alternator loose or you will have more smoke when the hot terminal hits that engine block. And trust me, it will. That seems to be where they are always drawn to. Make sure also to note where the spacers between the bolts and block go to keep the belt alined.
You still need to trace all the wires mentioned to make sure there are no bare spots that may cause you problems in the future.
 

gone2bch

Recruit
Joined
Aug 2, 2007
Messages
3
Re: Merc I/O problems... I Screwed up...

Another cure to your origional problem (dead battery) is to put a perko switch in and add a second battery. It is simple and cheap to do. The battery being the majority of the cost. It would keep you from being stranded on the lake as often.
 

Liberator 6

Seaman
Joined
Jul 13, 2006
Messages
50
Re: Merc I/O problems... I Screwed up...

More than likely, what smoked was the coating on your battery wires. Trace them both, the hot to the starter and the ground to the block.

Agree completely. Make sure you check the areas around the connections. They're probably discolored. In addition to your alt and battery testing, you may need to replace those two wires off the battery. To check you can whip out an Ohm meter and measure the resistance from tip to tip, it should be a VERY low figure if your cables are functional. Good luck!
 

cheburashka

Senior Chief Petty Officer
Joined
May 28, 2005
Messages
715
Re: Merc I/O problems... I Screwed up...

You haven't even verified that a dead battery was the problem in the first place. I'd bet that it wasn't. You sad that your boat battery wouldn't start it, so you tried your car battery. Then your car battery wouldn't start it. If two batteries failed to turn it over, and one battery was good enough to start your car, you know that the battery wasn't the problem. Also, there was enough juice in that battery to let some smoke out of your electrical system, so you can be pretty sure the battery wasn't dead. The alternator wasn't charting the battery while the boat was running--the battery was already charged and slowly discharging as you ran the boat. As you ran it, it depleted and got down to less than 12V, which is why you were dying under power. You have a dead alternator. Bet on it.

You also have a bad starter switch, solenoid, or other electrical problem in the starter circuit. Plus you have whatever other things may have gotten fried when you reversed the terminals. I'd start by replacing the alternator.

You've got to be methodical with electrical problems. If a known good battery didn't start the motor, the problem was clearly not the battery.
 
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