I need help, boat runs rough and stalls. I pumped new gas and lots more.. I need help

[Bayliner3.0]

Found main coil GM (AC Delco) part# 1115491
Ignition control module GM (AC Delco) part# ??

 

[alldodge]

Ignition modules are same for auto as marine, there GM parts

If you have a good digital meter and set it to the correct scale (not using auto function) then could be the coil is out of spec.

 

[Bayliner3.0]

Ignition modules are same for auto as marine, there GM parts

If you have a good digital meter and set it to the correct scale (not using auto function) then could be the coil is out of spec.

Right but Mercruiser wants $225. I found the latest one they use is AC Delco part# 19418839 about $125. But I might go with CDI on that $115 if I change it.(they claim better than OEM).
I found all the wire terminals going to it were drastically flared out. I popped them out and tightened them up. Can’t hurt maybe it will help..
I will try my other multi meter that is not auto just to compare.

 

[Scott06]

Right but Mercruiser wants $225. I found the latest one they use is AC Delco part# 19418839 about $125. But I might go with CDI on that $115 if I change it.(they claim better than OEM).
I found all the wire terminals going to it were drastically flared out. I popped them out and tightened them up. Can’t hurt maybe it will help..
I will try my other multi meter that is not auto just to compare.

Look on summit racing for the module I think their ac delco modules were under $100.

if those primary side coil ohms are accurate yes get new coil.

 

[Bayliner3.0]

Look on summit racing for the module I think their ac delco modules were under $100.

if those primary side coil ohms are accurate yes get new coil.

Going to retest coil, and I am going to remove my tachometer wire too. I read if it is shorting somewhere in the tach then it can mess with ignition. Just to rule it out. Replace coil as needed. Then restart it and see how it runs with wires tightened up and tach unplugged. Might screw in mixture if it knocks just to see what happens. Still an issue replace module.

 

[nola mike]

I'd be surprised if it's the coil. Low resistance measurements are tough to measure accurately esp if you don't have an awesome meter with known precision and accuracy. If you are getting a good spark then you're ignition is essentially working. The only thing would be if it's setting the timing correctly.

 

[Bayliner3.0]

I'd be surprised if it's the coil. Low resistance measurements are tough to measure accurately esp if you don't have an awesome meter with known precision and accuracy. If you are getting a good spark then you're ignition is essentially working. The only thing would be if it's setting the timing correctly.

Timing seems to be set right, but after a few minutes (with jumper and interrupter wires connected) it jumps to 6 degrees ATDC. What do you think? Distributer is not moving it is locked in place.
Module overheating, bad module? Tach shorting? Carb tune? Coil? This is all a nightmare and I am going to wake up soon with a good running boat?

 

[Bayliner3.0]

Expletive, expletive!! I have a short in my tachometer signal wire.
Also to no ones surprise, my MAIN COIL is GOOD. It tested 0.4 ohms on both ends with my other Multimeter. Multimeters should come with a 1ohm resistor to test them.

Could a shorted tach signal wire cause the module to throw off the timing? I just figured the module sent a signal to the coil (one way).
I looked at the wiring diagram and it seems to just go from main COIL to a TEST LEAD to a HARNESS PLUG to the TACH. So nothing else should be on that wires path. Nothing plugged into the lead, but shorted somewhere. I will start tracing it to find the short.

Could this be my problem or is this just a new issue I discovered??

 

[nola mike]

Expletive, expletive!! I have a short in my tachometer signal wire.
Also to no ones surprise, my MAIN COIL is GOOD. It tested 0.4 ohms on both ends with my other Multimeter. Multimeters should come with a 1ohm resistor to test them.

Could a shorted tach signal wire cause the module to throw off the timing? I just figured the module sent a signal to the coil (one way).
I looked at the wiring diagram and it seems to just go from main COIL to a TEST LEAD to a HARNESS PLUG to the TACH. So nothing else should be on that wires path. Nothing plugged into the lead, but shorted somewhere. I will start tracing it to find the short.

Could this be my problem or is this just a new issue I discovered??

Are you having a short to power or a short to ground? How are you testing that? What's your tach doing? I wouldn't think a short to ground on that wire would do much. Your tach wouldn't work. The module is just sending out a signal to the tach, it gets the rpm from the distributor.

 

[Bayliner3.0]

Are you having a short to power or a short to ground? How are you testing that? What's your tach doing? I wouldn't think a short to ground on that wire would do much. Your tach wouldn't work. The module is just sending out a signal to the tach, it gets the rpm from the distributor.

I was only checking continuity (signal wire removed from tach and unplugged at the coil). Tach seems ok until off and it sits above zero. It wasn’t the tach that made me check it. I read that a shorted signal wire can affect ignition. I just wanted to rule it out, and of course it had a short.
I didn’t check against ground or look for voltage. I just figure if I have ignition issues and one wire is shorted then fix it before moving on.
I traced over half the wire, I will continue tomorrow.

 

[Dillusion808]

Tach doesn't always go to 0 when turning motor off.

My 4.3L never did. If you are getting RPM readings I don't think its the wire shorted.

 

[Scott06]

I was only checking continuity (signal wire removed from tach and unplugged at the coil). Tach seems ok until off and it sits above zero. It wasn’t the tach that made me check it. I read that a shorted signal wire can affect ignition. I just wanted to rule it out, and of course it had a short.
I didn’t check against ground or look for voltage. I just figure if I have ignition issues and one wire is shorted then fix it before moving on.
I traced over half the wire, I will continue tomorrow.

It is somewhat common for tach to mess with getting a good spark. If I were in your shoes I would leave tach disconnected put original module back in and test it out

 

[nola mike]

It is somewhat common for tach to mess with getting a good spark. If I were in your shoes I would leave tach disconnected put original module back in and test it out

Wouldn't hurt to disconnect, but the HEI ignition doesn't use a traditional coil where grounding that wire would kill spark. I think we're getting way into the weeds here. OP problem is still probably fuel related. If the timing is +/- 5 or 10 degrees at idle it will probably idle fine

 

[Bayliner3.0]

Wouldn't hurt to disconnect, but the HEI ignition doesn't use a traditional coil where grounding that wire would kill spark. I think we're getting way into the weeds here. OP problem is still probably fuel related. If the timing is +/- 5 or 10 degrees at idle it will probably idle fine

I have the EST ignition if that makes a difference. It jumps to 6ATDC and starts knocking at idle, but RPM seems ok.

It is somewhat common for tach to mess with getting a good spark. If I were in your shoes I would leave tach disconnected put original module back in and test it out

Well with the tach disconnected the signal line has a short. So it is not the TACH itself.
I think to follow your testing I would need to push the signal wire out of the plug at the coil. I am going to find the short an fix it, if a harness is pinched somewhere another wire might be next. One way or another I will need a tach on my console. Becoming a massive thread huh…. I will follow up in a few days. Waiting on the rain to go away. Maybe Wed..

 

[Dillusion808]

I think still jumping in deeper than you need to right now.

I saw you pumped new gas but did you run it on a portable tank? Also might of missed this but are you sure you got the motor at TDC before even starting the timing procedure?

 

[Bayliner3.0]

I think still jumping in deeper than you need to right now.

I saw you pumped new gas but did you run it on a portable tank? Also might of missed this but are you sure you got the motor at TDC before even starting the timing procedure?

Deeper than I wanted to be that’s for sure. I never adjusted the timing, just checked it.
I will let you know in a couple days what the problem was….. Hopefully.

 

[nola mike]

Well with the tach disconnected the signal line has a short.

How are you determining that?

 

[Dillusion808]

Can you take a pic of the notch on the pulley and the timing gauge lined up?

This is jumping around so much I'm not sure steps are going in order.

 

[alldodge]

The motor has NOT jumped timing and there is absolutely no need to do any checks to check that it has not

 

[Bayliner3.0]

The motor has NOT jumped timing and there is absolutely no need to do any checks to check that it has not

I guess I shouldn’t have said jumps. I know the gears aren’t jumping teeth. No chain or timing belt. Pretty sure only the module can move the timing like this.