140 Merc coil question

[SHickey]

Hello,

I have been trying to get an old tin can ready for restoration or to sell outright. The boat is a 1972 Mirrocraft 21' with a 140 merc and a MC-1 outdrive. I got the motor running well this am, it started easily, and after I adjusted the 2 carb jet screws it was running like a top.

I decided to get my camera and record the motor running, outdrive shifting and all that. I started the motor and it ran for @ a minute and died. It turns over fine and is getting plenty of fuel but there seems to be no spark. I removed a spark plug, grounded it and did not see any spark.

I suspect the coil may need replacing but I was wondering if I could swap the coil I have on my 1976 165 motor and use it in the 140 motor as a test and if it works, I would replace the 140 coil. My question is if I could do any damage to the electrical system or the 165 coil if I use it as a test.

Thanks anyone who could respond to this question.

SH

 

[Alumarine]

It should be the same coil.
Originally they were both externally ballasted and should still be unless someone changed that setup.

 

[Starcraft5834]

a sparks a spark, some are hotter than others, hotter will result in more efficient fuel burn, the original coil set up likely is 15K volt... as marc said a ballast/resistor set up....folks have upgraded to electronic ignitions (I just did) on my 1987 140hp Merc.. the new pertronix coil is the 40K flamethower.. I removed the 15K old coil, . even if you didnt wire it to reduce voltage after start up,,(which I did) , only thing you'd do is potentially burn out your spark plugs quicker.. that said, it would run like crap with bad plugs.... what your talking about should be the same to swap out

 

[Bondo]

Ayuh,.... Have ya replaced the Points, under the distributor cap,..??

If not, That's where ya start,....

The Points, cause the coil to fire,....

 

[SHickey]

I have not changed the points, cap, or condenser. I can look at it tonight and see what kind of condition it is in. I haven't changed points in a motor in several years. Is there anything I should look at and try to adjust before I replace the points or should I just buy a point replacement kit and be done with it??

 

[Bondo]

Ayuh,.... Atleast drag a piece of emery cloth 'tween 'em to clean 'em, 'n check the gap,....

If the points ain't workin', changin' the coil ain't gonna fix nothin' either,....

I'd buy the kit. 'n install it,...

 

[SHickey]

Sounds good and thanks for the advice.

It's just funny how a motor could be purring along and just conk out w/o any warning. I learn so much about these old beasts every time I start a new restoration project. :faint2:

 

[SHickey]

Thanks again!!

On my way home from work I picked up a points kit and went to work. After replacing the points she fired right up much to my relief.

I threw the timing light on her and she is set to factory specs.

You guys save me so much time and frustration and I really appreciate all of the postings.

Take care!!

 

[SHickey]

Well,

I thought I was out of the woods with this old motor but now I have a different problem. Last night I set the timing and the motor ran great. Today the motor is running like crap and it does not idle.

The last thing I did last evening was to remove the fuel pump filter housing so that I could tighten down the distributor. I noticed the fuel pump filter was distorted and falling apart. I decided to toss it and will get a new one eventually.

Now I am wondering if the fuel filter in the fuel pump needs to be installed to restrict the fuel getting pumped into the carb. Since I removed the filter the motor runs great over 1500 rpm but under 1500 it seems to be missing and running really rough. I pretty much dies when it goes below 1000 and I get a big puff of blue smoke out of the carb.

Any ideas or suggestions will be greatly appreciated!!

 

[achris]

When you replaced the points, did you also replace the capacitor (some call it a 'condensor') at the same time? Sounds very much like the points are burning up. That's what that capacitor is there to reduce.

Chris.......

 

[SHickey]

I did replace the capacitor at the same time as the points and I set the gap at .022 as specified in the service manual. I readjusted the gap to 0.16 and that did not seem to make any difference.

Very frustrating.

Not sure if this makes a difference but I changed out the bad temp sensor and now the operating temp is maintaining @ 120-130 degrees.