Help! Boat won't start!! :-( (305 merc I/O)

[shwine617]

Hello everyone!, thanks for taking the time to help. So I finally got to use my Sea Tow after 5 years lol. It paid off though, the tow bill was $1200!!

OK here's my boat info: it's a 20' 1995 Crownline bowrider with a mercruiser 5.0 LX I/O. Carbureted with thunderbolt igniton.

Me and my father were trolling and the boat started to stumble a little. About 5 mins later it stalled. It would still run if I started it an reved it up in neutral, but once a load was put on it(put it in gear) it would stall out. Eventually it just stalled, then wouldn't run anymore.

I have to boat home now. It's tries to sputter and start but won't go. It's not a fuel problem, I believe it's spark related. I put a spark tester between the coil and distributor. It blinks a little dim and everytime it actually tries to start you can notice the tester gets brighter. Also when you turn the key off after cranking it will try to run and you can see the tester is blinking bright.
I don't want to start throwing ignition parts at it, because that could add up quick. If anyone can steer me in the right direction I would greatly appreciate it.
Thanks again!
Cory

 

[dubs283]

Re: Help! Boat won't start!! :-( (305 merc I/O)

how do you know its not a fuel problem??

have you checked the water separator?? fuel pressure??

your spark tester should go between the coil tower and ground, not the distributor

 

[shwine617]

Re: Help! Boat won't start!! :-( (305 merc I/O)

Thanks for the reply. It's getting fuel, the carb is brand new as of the beginning of the season. Also have a new seperator and I took it off and dumped it into a clear container and found no water in it. Mechanical fuel pump is working, Fuel bowl is full of gas and the squirters are working properly. The tester I have replaces the coil wire and has a see through fitting to see the spark light up.

 

[dubs283]

Re: Help! Boat won't start!! :-( (305 merc I/O)

The tester I have replaces the coil wire and has a see through fitting to see the spark light up.

yes

but you should still ground the end of the spark tester, not connect it to the distributor - this will let you see how the ignition system is operating independent of the distributor

here is a link to download a manual that has info for troubleshooting the t-bolt igntion system:

http://www.4shared.com/document/Kgl-Dq7d/Service_Manual_17.html

 

[shwine617]

Re: Help! Boat won't start!! :-( (305 merc I/O)

ok, I'll give that a try tommorow and let you know. I appreciate the input.

 

[shwine617]

Re: Help! Boat won't start!! :-( (305 merc I/O)

Ok, I hooked it up to ground instead of the distributor. It's pulsing a steady orange when cranking.
I'm not sure where to go from here, if anyone can give some pointers I'd really appreciate it.
thanks,
Cory

 

[krisnowicki]

Re: Help! Boat won't start!! :-( (305 merc I/O)

If you have a fuel water separator dump the contents into a container, look for water

 

[shwine617]

Re: Help! Boat won't start!! :-( (305 merc I/O)

Yes, I did that twice, there is no water present at all, even let the container sit overnight to check.

I just did this test:
Tests for Thunderbolt Ignition: W/ignition key on AND BILGE WELL VENTILATED OF GAS FUMES!!!

#1 - Connect your voltmeter neg. lead to the engine ground and pos. lead to the white/red wire terminal at the dist. It should read 12 volts.

#2 - If 12 volts is present, remove the coil spark wire from the distributor and connect it to a spark gap tester to ground. Remove the white/green lead from the dist. terminal. Turn the ign. key to on and strike the white/green lead to ground. If there is spark, replace the ignition sensor in the dist.

#3 - If there is no spark, substitute a new coil and repeat test #2. Now if you get spark, install a new coil. NO SPARK, replace ign. amp.

#4 - In #2, if there is No voltage present, disconnect the white/red wire and check it again for 12 volts. If 12 volts is present, replace the ignition sensor inside the dist. cap. If no 12 volts present w/it disconnected--ignition amplifier is shot and must be replaced."

Got to #2, the tester is flickering sparatically when I ground the white/green wire. It's not sparking as soon as I ground it, just sparatically.

Not sure if that means I have a bad ignition sensor?

 

[Don S]

Re: Help! Boat won't start!! :-( (305 merc I/O)

Just check for spark by pulling the coil wire off of the distributor cap, hold it about 1/2" from a good clean ground and crank the engine over. Should have a bright blue spark snapping across the gap.

 

[shwine617]

Re: Help! Boat won't start!! :-( (305 merc I/O)

Hi Don,
I did do that test and it was sparking nice

 

[Don S]

Re: Help! Boat won't start!! :-( (305 merc I/O)

Hook up a test lead from the batteries positive terminal, to the coils + terminal and see if the engine will start. If it does, you will have to disconnect the jumper to shut it off.

If it still doesn't start, disconnect one of the wires going to the shift interrupt switch and try it. With and without the jumper.

 

[shwine617]

Re: Help! Boat won't start!! :-( (305 merc I/O)

Thanks for the help everyone, it turned out to be a weak coil.
The boat is running great again!
I appreciate all the replies and God Bless