Igniton output

[tjello327]

Hello forum,
I have a 1986 125hp Force. I have been in the finale tuning stages of this thing all summer and I think that I may still have a small ignition issue. This engine still coughs a little when I try to start it after I ran it for a little while. Just a little cough, nothing over the top. I just set the static timing to 28 degress btdc and still coughs a little. I decided to revisit the ignition system one more time. I used a spark tester last night and all the cylinder jump about a 3/4" gap. I did notice that #3 seems just a little bit thinner than the others but does jump the same gap. Also this plug is a little wetter than the others. #2 also was a little wet too but the spark wasnt as thin as #3. I swapped around stator leads, no change. I swapped around coils, no change. I swapped around cdi leads, no change. I didnt swap around the trigger yet. I don't believe that could cause a weak spark? Anyone have any ideas if I might have some kind of issue here and if so, where should I look? I am sure a DVA tester would make things easy on me but I don't have one. This engine runs strong but only tops out the rpm at 4600 with a 18 pitch prop. Same as the 19 pitch I had on before. Carbs are getting full throtle, fuel pump is new, gas is fresh 50:1, bulb is firm, fuel lines are good. Could a weak spark on #3 do this?

Thanks,
Tom

 

[john from md]

Re: Igniton output

You might have a weak CDI circuit. Have you done the resistance checks in the book?

John

 

[tjello327]

Re: Igniton output

No I have not. I am not to sure how to do it. I have a Selco manual that I will check. That manual kinda sucks but I will give it a shot. thanks.

 

[john from md]

Re: Igniton output

Page 5-44 of the Seloc manual has all the info you need.

John

 

[tjello327]

Re: Igniton output

Thanks, I looked it up and it looks like there is no way around needing a DVA multimeter. I am going to try to find a good deal on one somewhere and do my testing that way. I am not sure if the spark is weak anyways because it is at least still blue. When I but the replacement stator on, some of the wires were to short so I soldered extentions on them and used heat shrink. I did'nt want to use crimp connectors because I thought that I would get a better connection with solder. I am starting to question my soldered connections. What is the proper technique to add length to the stator wire?

Thanks!

 

[john from md]

Re: Igniton output

Here is where to get the cheapest DVA adapter available (we have all been there).
www.esitest.com and do a search.

Why your wires were to short concerns me. A direct replacement shouldn't have had that problem.

As far as adding wires. The first thing to do is make it mechanically attached. That means twisting them together or crimping. Then, if you want a better electrical connection, you can solder the mechanical joint. Never use solder in place of a mechanical joint as the joint will fail from vibration.

If you are getting blue sparks, and the pulses are too fast to count, it sounds like your CDI's are giving the right voltage to the coils. If a CDI was weak, it would show as an orange spark at the coil as the input voltage to the coil would be lower than the 150-180 volts nesessary for a blue spark.

John

 

[tjello327]

Re: Igniton output

The stator that I am using now wasnt a new replacement, it is used from e-bay. Now that I think about it, the white wires that come from the CDI boxes and go to the terminal strip by the starter are the ones that I had to lengthen. the numbered wires that come from the stator and go to the terminal strip and CDI boxes just had the connectors replaced with new ones. I also believe that I may have lengthened the yellow wires that come from the stator. I just started it and ran it for about 10 minutes and it sounds pretty good. It sucks the gas down fast!

Thanks!

 

[john from md]

Re: Igniton output

One thing new Force owners learn fast is that Force engines were designed by the petroleum industry.

Happy boating,

John

 

[tjello327]

Re: Igniton output

Yeah, that is what I am starting to learn!

Thanks!