Boat doesn't start

[Luinator]

I have a 2003 sea ray bowrider with a mercruiser 4.3 with an alpha outdrive. I took the boat out it started right up went about 100 yards and she quit. I spent about an hour cranking it, going a few yards and then dying again until i got back to dock. When i got home she wouldnt crank period. I checked for voltage at the ignition coil and there was none when hooked up. When i removed the positive and tested it connected to nothing there was voltage while cranking. So i replaced the ignition coil and still will not crank. I tested the voltage at the ignition coil and still no voltage hooked up but when removed positive from coil and tested it had voltage again. I did pull the spark plugs and they weren't firing either. Everything i know and opinions of the automechanics i know point to the icm. But i would like to verify everything before dropping 4-600 bucks on the ignition control module. Any ideas or other possibilities?

 

[fhhuber]

sounds like failure to supply fuel as fast as the engine needs it.

 

[Luinator]

I did just fill the boat up. Is it possible to overfill with gas and cause this? I topped it off trying to see how much fuel i used from the previous long trip. I don't normally top off.

 

[alldodge]

Howdy

I could use a bit more info to help, have the motor serial number available?
Is this an MPI or TBI motor?
Did it start and then die afterwards or doesn't fire at all prior to getting it back to the dock?
What is the status of your battery after all that cranking?

 

[redmen62]

sounds like failure to supply fuel as fast as the engine needs it.

Seeing as the plugs aren't firing, and he's got no power at the coil... I don't see how it's fuel related

 

[Luinator]

Serial is 0m640252 and it has a carburetor

 

[Luinator]

Yes it started back up a fee times headed back to the dock. The batteries still have 12.5 volts on them. I have 2 with a master switch

 

[H20Rat]

Going to say the obvious, but... Kill switch? Even if the lanyard is connected, verify that it is good with a meter.

 

[Luinator]

Sadly i did check the kill switch. It is working like a champ.

 

[alldodge]

I'm with fhhuber, and it being a fuel issue and have a theory but lets check spark first. Here is the TB-V troubleshooting chart

 

[Luinator]

I will run through your flow chart this evening but where it says check for voltage at ignition coil. It says if its 0 volts check the engine and wiring harness. Now i already checked there and there is not voltage when the wire is connected to the ignition coil but there is voltage when i remove it from the coil. So thats what lead me to believe it was the coil or icm.

 

[alldodge]

there is not voltage when the wire is connected to the ignition coil but there is voltage when i remove it from the coil

This being the case I would guess you have a bad connection being caused by corrosion, loose or bad switch. Things in line are the kill switch and the key switch.

 

[Luinator]

the kill switch connects directly to the coil? it is a purple wire and the wires on the kill switch are purple. there is no purple wire on the key switch though. so the key must run to something and then to the kill switch.

 

[alldodge]

the kill switch connects directly to the coil? it is a purple wire and the wires on the kill switch are purple. there is no purple wire on the key switch though. so the key must run to something and then to the kill switch.

Your right, the kill switch is not in the mix but the key switch is, along with engine 10 pin connector

 

[Luinator]

I started going through the flow chart and there is no voltage on the ignition coil using the ground on the coil but if i use a different ground there is 12 volts. Looking at the wiring diagram the ground comes from the tac but the flow chart above says ensure the grey wire on the tac is not shorted to ground. Is this a miss print? If not how does the coil get a ground? Also my tac reads 1k now so it does appear to be bad, first time i nooticed it. I tried to put a ground straight to coil and it doesn't start. I'm going to troubleshoot further with flow chart but if any assistance gathered would be appreciated

 

[alldodge]

The coil is grounded by its body. The (+) pos side goes to 12V, the (-) neg side goes to the tach and the distributer control module. When the distributer is rotated by the motor the pickup inside the distributer signals the module to ground the (-) side of the coil. When this side is grounded the field in the coil drops and this causes energy to be released thru the output lead.

You should remove the gray wire going to the tach to make sure it is not causing the issue. Once you get it running you can reconnect if the tach was not the problem. The tach gets its input signal from the gray wire at the coil

 

[Luinator]

When i was testing the red white wire i saw it had voltage and i put it back in and the engine turned a little. After that i put it back together and tried to start the boat. And wow it started. It ran for 5 minutes then i went into the engines and started wiggling wires. It eventually cut off while i was wiggling the wires at the coil. So i replaced those connectors. It did not start. So i replaced the bullet connectors on the red white and green white connectors and it still doesn't start.

While it was running the tac worked fine but i have since removed the grey wire and it still doesn't start.

 

[Luinator]

Finished the flow chart and ended with bad icm. Guess i will order one

 

[alldodge]

Finished the flow chart and ended with bad icm. Guess i will order one

Hope that fixes the issue, fingers crossed

 

[Luinator]

Well i put the icm in and no luck. I ended up getting the ignition sensor assembly thats in the distributor and tried that. I swapped the sensor and nothing. I put the icm back in to give the combination of the two a whirl and what do you know she fired right up. We spent the whole day on the boat today. It was 95 degrees out and an awesome time. Thanks for all your help!!!