Dual battery switch switched while the engine was running

[1977FiberFormVolvo350]

MPI = Multi Port Injection
TBI = Throttle body injection

Looks like you have closed cooling, old style exhaust and the crab style cap, wonder how that happened.

The flat crab style cap gives all kinds of issues.

Where can I find a replacement cap?

 

[Scott Danforth]

While I have you here and I'm asking questions... That clear yellow hose coming off the carb; what is that?

that is the vent line from the fuel pump. if the fuel pump ever fails, fuel will be present in the tube. it is redirected in a boat to the carb to prevent fuel in the bilge which becomes an explosion.

 

[alldodge]

While I have you here and I'm asking questions... That clear yellow hose coming off the carb; what is that?

To add to what Scott said, I'm thinking you installed the motor, and if it has a mechanical fuel pump then the line goes on it. If the pump does not have a port for the line then it's an automotive type and needs to be replaced

The cap can be found at many auto parts houses, the Merc part number is 8M6001106

 

[Senior B]

You have a very simple motor and set up so this problem should be very easy to find. My bet is that you have blown main fuse or circuit breaker to the ignition. Check to see if you have 12Volts at your coil when the key is on. If you don't then find out why.

 

[1977FiberFormVolvo350]

Hey gentlemen, I made it down to the boat tonight. Here's some thing I found. #1 I have a 11.68 volts coming from the battery. Coming out of the coil with the key on I have 7.93. When it is turning it over it was all over the place. Sometimes 2 all the way to 9 volts. Mostly it hovered around 4-5 volts. I also noticed that the coil was really hot! Like burn my hand hot. This was before I starting turning it over. I'm thinking its the coil... Am I right?

 

[alldodge]

Hey gentlemen, I made it down to the boat tonight. Here's some thing I found. #1 I have a 11.68 volts coming from the battery. Coming out of the coil with the key on I have 7.93. When it is turning it over it was all over the place. Sometimes 2 all the way to 9 volts. Mostly it hovered around 4-5 volts. I also noticed that the coil was really hot! Like burn my hand hot. This was before I starting turning it over. I'm thinking its the coil... Am I right?

Something is not right here, you have the crab style distributer cap but your readings are similar to points.
Voltage reading of 11.68 volts says you either have a bad battery or volt meter.
The 9 volts and less during start is leaning me to you have a resistance wire still connected, and with electronic ignition it should be steady at 12V

 

[1977FiberFormVolvo350]

Here's a picture of the distributor and coil

 

[1977FiberFormVolvo350]

Something is not right here, you have the crab style distributer cap but your readings are similar to points.
Voltage reading of 11.68 volts says you either have a bad battery or volt meter.
The 9 volts and less during start is leaning me to you have a resistance wire still connected, and with electronic ignition it should be steady at 12V

Resistance wire? I guess I'm confused how switching the switch would cause this problem... The thing ran like a champ before this?

 

[alldodge]

You have a mixed bag of years going on and we all will have a more difficult time trying to figure out where to start. Looks like you have a late 70's or early 80's exhaust system with a 2000 something ignition system. The issue I have is trying to figure out what manual to review to determine what the issues are. I'm going to look at the carb cap distributer to start with and try to determine best path forward. Will take some looking, but will get back with later

 

[alldodge]

First you battery is to low at 11.6V, and if correct either needs recharged or replaced.

But should go back to the basics as Senior B mentioned. Take your volt meter start at the battery and work you way through the switch, to the starter and on in thru main breaker, then to the coil. If you have 12V at the coil, remove coil wire and use a spark gap tester and crank motor.

Also noted there is some corrosion on the coil terminals.

 

[1977FiberFormVolvo350]

Okay. Thanks for the advice. Is it normal for the coil to be hot? Also, I know why the battery was showing low... It was low from cranking when I ran down. Had to get shore-power adaptor to get my charger hooked up. Also, I attached a picture to this post of what I think is a breaker. Any thoughts of whether this could be it? If so, pushing it does nothing. Should it be replaced? If this is the culprit I probably wouldn't have any voltage at the coil right? Would it behoove me to just replace the coil and give it a shot? Only $50 and easy to replace is my thought.

 

[alldodge]

The coil shouldn't get hot, and with electronic ignition you should have a coil with an internal resistor, not to be confused with one marked "use with external resistor".

The pic posted is your main engine circuit breaker, and if it does nothing when pressed that is normal. Since your able to crank the motor over it's should be good. Need to find out if your getting power to the coil. Also on the negative side of the coil I would remove the tachometer wire. Check voltages before replacing parts

 

[1977FiberFormVolvo350]

I think I'll just replace the whole distributor. Can any of you suggest a distribution system?

 

[1977FiberFormVolvo350]

First you battery is to low at 11.6V, and if correct either needs recharged or replaced.

But should go back to the basics as Senior B mentioned. Take your volt meter start at the battery and work you way through the switch, to the starter and on in thru main breaker, then to the coil. If you have 12V at the coil, remove coil wire and use a spark gap tester and crank motor.

Also noted there is some corrosion on the coil terminals.

I tested volts. Pretty consistent everywhere but the coil. Can I hook something up direct to the coil?

 

[alldodge]

I tested volts. Pretty consistent everywhere but the coil. Can I hook something up direct to the coil?

The coil should stay constant, but again you have a mix bag of stuff. The distributer I see appears to be a GM electronic distributer used on 2001 and newer V8's. The coil is not the same that is used with the distributer. If you want a change I would use the Delco EST model

 

[1977FiberFormVolvo350]

Should I just replace it all?

 

[1977FiberFormVolvo350]

The coil should stay constant, but again you have a mix bag of stuff. The distributer I see appears to be a GM electronic distributer used on 2001 and newer V8's. The coil is not the same that is used with the distributer. If you want a change I would use the Delco EST model

Should I just replace the whole distributor and coil? If so, is pertronix (from Amazon) the way to go?

 

[1977FiberFormVolvo350]

It's a Mallory Unilite distributor. I'm gonna order a new module and replace. Will let you know what happens

 

[alldodge]

Sounds good, and BTW the Mallory and MSD distributers have been having quite a bit of failures these days. Not saying that is the issue but it leans that way.

As for the Petronix ones, many have installed and most have been fine, but there are also some that have had issues. They also have only one timing curve for every motor, which means it works but not set for best performance

 

[1977FiberFormVolvo350]

Solved!!! It was the spark module after all... Installed that and it fired right up! Thanks so much for your help!