Boat Wont Start after putting in alternator.

[hazpay1]

After starting my 1995 Mercury 5.0L this season, I noticed my volts were only reading 10 on my dashboard gauge. Slowly but surely the volts dropped below 10 and I thought it was time to change the alternator. After installing the new alternator, I now cant get the boat to start. It cranks over but it wont fire. I have spark and I checked most fuses. Please help. Thanks Bill. It seems as if the battery has enough power to start the boat. The funny part is just before I installed the alternator, the boat started fine.

 

[bomar76]

Re: Boat Wont Start after putting in alternator.

Did you charge the battery?
If it only shows 10 volts at rest it doesn't have nearly enough juice to start.

 

[hazpay1]

Re: Boat Wont Start after putting in alternator.

Ok just found out that the old alternator was fine....Had it bench tested. I guess my next step is to check the battery...

 

[bomar76]

Re: Boat Wont Start after putting in alternator.

And just for future reference...
a $3 Harbor Freight Digital Volt Meter would have shown you if the alternator was bad or not.....13.6 volts plus or minus indicates a good output.

 

[chiefalen]

Re: Boat Wont Start after putting in alternator.

if it was showing 10volts when running something was wrong with the alternator,or wiring.maybe a wire broke.when at rest should show 12 .6 or something like that 10 volts is a dead battery maybe won't even hear clicking.all the plugs in at the coil.center plug in good?

 

[tysonnathan]

Re: Boat Wont Start after putting in alternator.

if it was showing 10volts when running something was wrong with the alternator,or wiring.maybe a wire broke.when at rest should show 12 .6 or something like that 10 volts is a dead battery maybe won't even hear clicking.all the plugs in at the coil.center plug in good?

You are assuming that the voltage meter on the boat is reading correctly. I would check it with a handheld meter before I started tracing wires. If it is at 10v, trace the wires to the voltage regulator and make certain that everything is hooked up correctly there.

 

[Dadicus]

Re: Boat Wont Start after putting in alternator.

Have the battery checked at the same place that checked the alternator. And I agree about getting a small meter to confirm the voltage for yourself.

You'll also want to check the main connections and cables. I had a battery cable once that got corrosion inside the rubber, where I couldn't see it. It worked, sort of, but caused a drop in voltage. Eventually the cable failed completely and I found the corrosion, but that was after several days of looking for more complex problems. Turned out to be something simple and cheap.

 

[hazpay1]

Re: Boat Wont Start after putting in alternator.

Ok heres where I am at now. Load tested the battery...seems to be fine. A little weak but fine. Dropped to about 10 volts during load test. Standing alone it reads 13V. Alternator bench test came back ok. Seems like i have a short somewhere. Any help or ideas where I should start too look? Ignition seems to be working...Thanks to all that have posted. Bill.

 

[Dadicus]

Re: Boat Wont Start after putting in alternator.

Try using a jumper cable to jump the main positive and main negative (ground) cables. You may also want to try a battery you KNOW is good.

 

[thunderroad]

Re: Boat Wont Start after putting in alternator.

I wouldn't think it would cause it not to start, but dropping to 10 volts under load isn't all that great.

 

[RJLeuwen]

Re: Boat Wont Start after putting in alternator.

Make sure the 2 small wires on the Alt. are properly connected purple to purple and red to red. Then look on the battery post on the starter is there a square block with an Ornge wire attached to it? If there is that square block is a 90 or 110 amp fuse and the ornge wire is the charge wire from the ALT.
and is most likely blown.

RJ