HELP ME PLEASE!!! 1978 Mer will not spark but i have good power to new coil

justalilbit08 · Jul 26, 2009

I have 78 mer 140 i have tried everything i can think of, i changed the....

battery
coil
plugs
wires
cap
points

i am getting good power to both sides of the coil and i am still not getting a spark!!! i have tried everything i can think of. please help me, also the boat cranks over fine but just no spark

RaScLeS · Jul 26, 2009

Re: HELP ME PLEASE!!! 1978 Mer will not spark but i have good power to new coil

mostly powerpack issues affecting these motors. is it not sparking on all cylinders ? or some ?

justalilbit08 · Jul 26, 2009

Re: HELP ME PLEASE!!! 1978 Mer will not spark but i have good power to new coil

its not sparking on any of the cylinders

justalilbit08 · Jul 26, 2009

Re: HELP ME PLEASE!!! 1978 Mer will not spark but i have good power to new coil

and what do you mean by powerpack issues is that something i can change all together?

blackbox · Jul 26, 2009

Re: HELP ME PLEASE!!! 1978 Mer will not spark but i have good power to new coil

i had more problems with the triggers(distributor housings) back in the 1980s, than any other ign. part. you may be able to find a used ign. system from a parts motor, lots of old in-line 6 motors in bone yards.
good luck!

Chris1956 · Jul 27, 2009

Re: HELP ME PLEASE!!! 1978 Mer will not spark but i have good power to new coil

First of all a 1978 Merc 1400 does not have points. Also, one side of the coil is grounded, and the coil is pulsed by the switchbox, to induce a spark. There is no way to have power on both sides of the coil.

It also uses a hall effect sensor in the distributor. There is a test for the battery-powered CDI ign system on this site as well as the CDI Electronics web site.

You might post the serial number, so we can figure out what you have.

JustJason · Jul 27, 2009

Re: HELP ME PLEASE!!! 1978 Mer will not spark but i have good power to new coil

is this a sterndrive? if so... you posted in the wrong section.

justalilbit08 · Jul 27, 2009

Re: HELP ME PLEASE!!! 1978 Mer will not spark but i have good power to new coil

chris1956 the serial number is 5458529

model is MCM 140

and as far as the coil + and - i checked and thereis running power from both sides

justalilbit08 · Jul 27, 2009

Re: HELP ME PLEASE!!! 1978 Mer will not spark but i have good power to new coil

as far as the cap and points i pulled the cap and when i turn it over i can see the points working and the cap spinning, everything looks good but still....no fire

sschefer · Jul 27, 2009

Re: HELP ME PLEASE!!! 1978 Mer will not spark but i have good power to new coil

Do you think it's possible that someone tried to convert this distributor at some point. The parts diagram doesn't show any points but it does show a switchbox.

bclery · Jul 27, 2009

Re: HELP ME PLEASE!!! 1978 Mer will not spark but i have good power to new coil

Sorry if this is a dumb idea, but..

There is probably a kill line from the switch box to the ignition key. Have you disconnected that or made sure it is not shorted to ground?

Is there any kind of rev limiter on that model? Did you disconnect that ?

Laddies · Jul 27, 2009

Re: HELP ME PLEASE!!! 1978 Mer will not spark but i have good power to new coil

MCM 140 is a chevy 181 cu.in engine not a outboard.

sschefer · Jul 27, 2009

Re: HELP ME PLEASE!!! 1978 Mer will not spark but i have good power to new coil

Well I'll be danged. No wonder it won't start.

justalilbit08 · Jul 29, 2009

Re: HELP ME PLEASE!!! 1978 Mer will not spark but i have good power to new coil

thak you guys awesome help it is running now!! but new problem i am going to post it.

HELP ME PLEASE!!! 1978 Mer will not spark but i have good power to new coil

Cadet

Petty Officer 1st Class

Cadet

Cadet

Seaman

Supreme Mariner

Vice Admiral

Cadet

Cadet

Rear Admiral

Recruit

Banned

Rear Admiral

Cadet