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Help Honda BF40A Wont Start No Spark

4

40honda

New member
Hello All,
I was trolling on the lake yesterday for few hours and boat ran fine no issues came home added some engine oil and tried to start the motor but it wont start it just cranks.
I have pulled spark plugs and tested for spark no spark on all 3 coils.
Tested to see if power comes from CDI to the coils nothing no power.
Checked all connections and grounds everything is good nothing broken or loose.
Checked coils it reads 13.12 ohm on all 3 of them.
Checked pulser it reads 306 ohm
Checked exciter it reads 5.95 m ohm
I also have checked the kill switch and it works as it should no open ground.

Im not shore if my CDI ignition unit is fried is there any way to test it?

I don't have manual book to check if the resistance for above parts is correct.

please let me know if you have any suggestions.
 
Last edited:
There are three pulsers....hopefully, they all measure the same.

I would recheck your exciter coil. In the pre 2004 models, it should be between 168 and 227 ohm. 2004 and newer should be 7.02 to 8.58 ohm.

There is a resistance test for the CDI...it is a matrix of resistances between all of the pins on the connector. I have never done it.

I check for electrical output from all the pulsers and the exciter going into the cdi. I do not know the exact voltages, but the pulser output is relatively low (maybe a few volts)...but they should be the same.

The exciter should be a bit higher...100 v or so.

Then you check the voltages going to the spark coils.

If you have good voltages, going in....but nothing coming out to the spark coils and you have opened the kill switch lead(to assure that it is not grounded), then it is the cdi.

But first recheck that exciter and while you are at it be sure that you checked that there is no ground on the kill switch lead (black/red).

It is very unusual that spark would stop that quickly. That is why I am also suggesting to recheck that kill switch. Most people think that if it is shorted to ground, that is good. Shorting to ground, stops the spark.

Mike
 
Thanks Mike for the info,
I have rechecked everything last nite night and these the are the numbers.
Pulser 309 ohm on all 3 coils all good per manual
Exciter wont show any ohm's it it only shows few when the magnet is moving manual calls for 168-227.
Checked all 3 coils 3.4 , 2.96, 2.98 ohms all good per manual.
Rechecked the red black wire when safety clip removed it grounds, clip applied it flows current also removed the connector and no change.
I haven't checked Pulser or Exciter for Volts jet.
There is no voltage going to spark coils.

I also noted the Exciter is cracked on few spots and smells like burnt rubber.
So far to me it looks like the Exciter is bad and is not making the charge the CDI needs to send voltage to coils.
i hope this is the issue as they are chep $15 used online.

Please letm me know what you think.
also I have found Honda manual online for free.
thanks for all the help
 
I have taken small hammer and hit the exciter slowly and it started to read 185 ohms but when i move it around it goes to zero, I can see it started to separate where connections are.
I will order used one and will test again when i get it.
thanks,,
 
Just gut back from hunting trip on Tuesday and yesterday i have installed the used exciter and motor fired right up on first try, this was easy and cheap repair the motor starts faster with this exciter, with the old exciter i remember it used to crank longer time as the spark was weak.

Thanks,,,,
 
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