140 mercruiser no spark help!!!!!

[michaeli84]

Re: 140 mercruiser no spark help!!!!!

Thank you, bruceb58 for your help i appreciate it alot man.

 

[Bt Doctur]

Re: 140 mercruiser no spark help!!!!!

1) remove all the wires from the coil.
2) run a jumper from the + battery to the + side of the coil.
3) take another jumper to a good ground and "scratch" the neg post.This should produce spark
4) hold points open with a matchbook, using a meter on ohms, attach one side to the black wire going to the dist. and the other to a good ground.
reading should be infinity, remove matchbook, reading should go full scale ,0 ohms. crank motor, meter should jump with the opening and closing of the points.
5) with key in "run " position there should be power to the + side of the coil on the purple wire

3) Yes or No
4) Do you get these readings?
5) Yes No
A bad tach will kill the spark too ,the gray wire, and the shift interupter will do the same

 

[bruceb58]

Re: 140 mercruiser no spark help!!!!!

I set the points with a feeler gauge 0.022 i dont have a dwell meter and yes i tried everything you said still nothing man. I ve been reading through the book to try to find whatever solution possible. the reson why i checked the switch is because i tried everything so i moved on to the next suggestion.

when you checked the gap, did you have the points open at the highest point of the cam lobe?

 

[michaeli84]

Re: 140 mercruiser no spark help!!!!!

when you checked the gap, did you have the points open at the highest point of the cam lobe?

yes, i went by the book i did it twice on the old motor and it worked fine. I changed out the shift interupt switch but i didnt try it yet. I also did a test where i unhooked the negative wires and with the points at their widest gap hooked a 12 volt test light to the negative and to ground and had juice according to the book that meens the coil is no good . I have 2 coils whats the chance of both of them being bad ya know.

 

[michaeli84]

Re: 140 mercruiser no spark help!!!!!

1) remove all the wires from the coil.
2) run a jumper from the + battery to the + side of the coil.
3) take another jumper to a good ground and "scratch" the neg post.This should produce spark
4) hold points open with a matchbook, using a meter on ohms, attach one side to the black wire going to the dist. and the other to a good ground.
reading should be infinity, remove matchbook, reading should go full scale ,0 ohms. crank motor, meter should jump with the opening and closing of the points.
5) with key in "run " position there should be power to the + side of the coil on the purple wire

3) Yes or No
4) Do you get these readings?
5) Yes No
A bad tach will kill the spark too ,the gray wire, and the shift interupter will do the same

how do i know if i have a bad tach?

 

[Maat222]

Re: 140 mercruiser no spark help!!!!!

yes, i went by the book i did it twice on the old motor and it worked fine. I changed out the shift interupt switch but i didnt try it yet. I also did a test where i unhooked the negative wires and with the points at their widest gap hooked a 12 volt test light to the negative and to ground and had juice according to the book that meens the coil is no good . I have 2 coils whats the chance of both of them being bad ya know.

NO!
When the points are open, you SHOULD have juice at the negative side of the coil.
This is extremely basic stuff.

The flow is from the battery, to the switch, to the coil +, out the coil -, and then through the points, to the condenser and ground.
If you rotate the engine to where the points are closed, you should be able to push the points open and closed by hand, and see a small spark at the points, and see a test light attached to the coil - go on and off.

After you try this, then we can start to narrow it down a little, but you have not told us anything really yet.

 

[michaeli84]

Re: 140 mercruiser no spark help!!!!!

if i could show you the book i would but thats what it says man

 

[michaeli84]

Re: 140 mercruiser no spark help!!!!!

i know but i dont know i just want to go fishing!!!! to me reading a level is far easier than using the test light its no problem to get the bulb to light but if you dont know when its suppose to and if its in the right spot or if its the right volts or i dont no im learning hopfully im not getting you guys mad at me but from reading all these different post and then trying it myself i get mixed up and i might do or say something wrong by accident so sorry if i ruffled your feathers a little man thanks for your input im past that prob and im on to the next 20 things that are not functioning properly. mike thanxs

 

[homey88]

Re: 140 mercruiser no spark help!!!!!

Its possible that you have a bad wire on the key switch or the back of the amps/volts gauge in your dash. I had a bad wire running from the switch to the gauge and that happened to be the one for the ignition/coil. Found it doing a wiggle test, wiggle the wires gently while trying to fire the coil. if you get a spark you will know where to start. This is just a suggestion, but it worked for my problem. I was in the same boat so to speak.

Brian

 

[jeffkrol]

Re: 140 mercruiser no spark help!!!!!

Its possible that you have a bad wire on the key switch or the back of the amps/volts gauge in your dash. I had a bad wire running from the switch to the gauge and that happened to be the one for the ignition/coil. Found it doing a wiggle test, wiggle the wires gently while trying to fire the coil. if you get a spark you will know where to start. This is just a suggestion, but it worked for my problem. I was in the same boat so to speak.

Brian

Though I have limited experience in boat motors, one thing I found is ALWAYS check your switches, especially if you have one of those safety kill switches.. Just rebuilt an ignition system on a 470 (needed it anyways) only to find out a 2 year old kill switch (aftermarket c$%p) failed. This was, in my limited boating experience, the second such failure ( friends pontoon, same thing)...

 

[michaeli84]

Re: 140 mercruiser no spark help!!!!!

when your at 3000 rpm how fast are you going it seems like im only going about 15mph is that normal it barely planes out

 

[APPALOOSA2]

Re: 140 mercruiser no spark help!!!!!

Well you did not say what was the cause of the motor not starting ?

Now you want to know at 3000 rpm how fast other peoples boats go.

Is your motor running smooth ?

What hull do you have ?

What prop do you have ?

What RPM are you turning at wide open throttle ?

I think you are starting to lose people.....who are just trying to help you !

 

[michaeli84]

Re: 140 mercruiser no spark help!!!!!

i messed up and sent the wrong post the no spark is old people leave me new messages and when i answer that comes up i got spark and the boat is running i have a 19/5 sea sprite not sure of the prop size its the same one that was always on the boat i went from a 3.0 130 to a 140 i dont know if that would make a difference or not

 

[michaeli84]

Re: 140 mercruiser no spark help!!!!!

how do i make it stop saying 140 no spark im new to this whole forum thing