Mercruiser 3.0 140 dying out

[Cseethree3]

I inherited a very nicely kept for 86 17 footer with a merc 140 on it, and it’s a nice boat, It’s been on the water and it’s a lot of fun, I recently installed a electronic ignition and kept the standard oem coil and it ran well with a couple hiccups but yesterday while on plane and cruising it started sputtering and then died out, it would start and cruise rough at 6 mph but if I went harder on the throttle it would cough and die out. Also if you go from reverse to neutral it will die out and cough through the carb, ran real well before this

I’m suspecting carb issues but I’m new to boats and didn’t know if there was other issues, I did change the fuel
Filter a couple years back

I’m a high performance small engine mechanic so learning quick about boats

 

[alldodge]

would start and cruise rough at 6 mph but if I went harder on the throttle it would cough and die out. Also if you go from reverse to neutral it will die out and cough through the carb, ran real well before this

I did change the fuel Filter a couple years back

Sound like fuel system, running out of fuel.

Remove fuel line and place into a container, then crank motor to see if you get a good stream of fuel pulsing

Place container under fuel pump and remove filter. Is there anything but clean gas? What does filter look like?

 

[kenny nunez]

Also check the filter at the carburetor inlet.

 

[Cseethree3]

Sound like fuel system, running out of fuel.

Remove fuel line and place into a container, then crank motor to see if you get a good stream of fuel pulsing

Place container under fuel pump and remove filter. Is there anything but clean gas? What does filter look like?

I will do these things, I did not change any other filter than the one that looks like it’s on the fuel pump? You think that can still cause an issue when it’s going from slow reverse to neutral and it coughing and dying too? Just weird to me

Thanks so much

 

[alldodge]

When shifting it might be the shift interrupter on the shift plate. The interrupter is used when coming out of gear to neutral. The dying issue right now appears to be more fuel so I would fix that first before adjusting shift, might just induce another problem.

 

[Scott Danforth]

also, the ignition should be points. if the points are not properly set, you could have similar trouble.

When was the last time the dwell and timing were set?

 

[Cseethree3]

also, the ignition should be points. if the points are not properly set, you could have similar trouble.

When was the last time the dwell and timing were set?

It’s now an electronic ignition, ran fine prior on both but it would eat condensers

 

[Scott Danforth]

I recently installed a electronic ignition and kept the standard oem coil

which kit did you install? the pertronix or Delco EST? if pertronix, is it a points conversion

 

[Cseethree3]

which kit did you install? the pertronix or Delco EST? if pertronix, is it a points conversion

Pertronix, use the OE coil though

 

[Scott Danforth]

Did you verify the resistance of the coil? Wired with a ballast resistor?

 

[Cseethree3]

Did you verify the resistance of the coil? Wired with a ballast resistor?

I didn’t measure the resistance as it ran completely fine for the 5-6 times I have had it out since installing it

 

[Scott06]

I didn’t measure the resistance as it ran completely fine for the 5-6 times I have had it out since installing it

I thought pertronix needed full 12 v to work

Might test spark with spark gap tester

Look at fuel filter in bottom of fuel
Bowl on pump

What do spark plugs look like

 

[Dubed]

I thought pertronix needed full 12 v to work

My pertronix needed a full 12 volts and a 3ohm coil. Resistance wire deleted

 

[Scott Danforth]

I believe (not positive) igniter II and igniter III are different. I believe one requires a ballast and one does not.

 

[Dubed]

I believe (not positive) igniter II and igniter III are different. I believe one requires a ballast and one does not.

I don't fully remember either. But, I think a lot of problems with the pertronix comes from not having matching coils and not installing or wiring correctly

 

[Cseethree3]

I don't fully remember either. But, I think a lot of problems with the pertronix comes from not having matching coils and not installing or wiring correctly

But how does that make it randomly have issues ran fine how it’s currently running, it definitely does not need the coil as it even said it didn’t and many warned against that coil