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Jason
Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 14294
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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No spark, 9.9 mercury el long shaft. tried everything, but

Customer Question

no spark, 9.9 mercury el long shaft. tried everything, but cant diagnose whu no spark. do not know how to do add'l test to determin why no spark
Submitted: 1 year ago.
Category: Boat
Expert:  Jason replied 1 year ago.
Hello my name is ***** ***** am I speaking with?
Do you have a decent quality digital volt/ohm meter, and do you know how to take resistance measurements? If yes, all Mercurys are cataloged by serial number, can I get that number please.
Customer: replied 1 year ago.
My name is ***** ***** have a good meter, but not know how to take reistance measurments. OD247916
Customer: replied 1 year ago.
we had a friend test ignition coils, and got a reading from one but not the other? I was not there. Seems like a kill switch maybe? but starter motor does spin when key is turnd, so we don't think it is the on/off swithch (or some hidden kill swithch.safety alot of boauts have.....but not sure. The boat was working fine until end of last season, then just went dead.
Customer: replied 1 year ago.
we confirmed spark plugs are good. It would be odd if the ignition coil or coils went dead, or so I am told. One is blue and one is black, as if one had been replaced at some time in the past. The motor is in good clean shape and not used very much over its life. We have had it 10+ years
Expert:  Jason replied 1 year ago.
Hey Steve. I can't teach somebody how to use a meter, that would have to be something you would have to know own your own. I can tell you to start by disconnecting the black/yellow on the switchbox and see if spark returns or not. But after that there isn't much we can do. Do you want to at least try that and see what happens?
Customer: replied 1 year ago.
Yes. My 80 year old father and myself 50 know enough to test with the meter, just not enough to converse intelligently. The boat is right here in my garage, and i will go look for the yellow/black wire and disconnect.
Customer: replied 1 year ago.
switch box, bottom wire, back and yellow, ....i disconnected....still no spark to either plug
Customer: replied 1 year ago.
(Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Jason replied 1 year ago.
They used a couple of different style ignition systems on these engines. Can you tell me what all of the colors of each wire are at the swichbox?
Customer: replied 1 year ago.
we have the meter out and ready to test resistance if you could advise please.....
Customer: replied 1 year ago.
I reconnected black/yellow wire and checked for spark...still no
Customer: replied 1 year ago.
wires on switch box, from top down...brown/yellow.......black/yellow......brown/white.....black/white.......black/yellow....
when i went to look again for this info...i noticed second wire down also black/yellow....so i disconnect both black/yellow....still no spark
Expert:  Jason replied 1 year ago.
Disconnect black/white. On the stator side of the wire. Measure between black/white and a good engine ground. What do you get for a resistance reading?
Customer: replied 1 year ago.
checking resistance again on ignition coils and we are getting a reading from one, but not the other....if this helps
Customer: replied 1 year ago.
i have wire diagram from book in front of me, it looks like they call the wires brn/white, brn yellow, blak/white, blk yellow, green white, and black yellow....very hard to read so small
Expert:  Jason replied 1 year ago.
Are you getting my replies? Do you see my last reply?
Customer: replied 1 year ago.
Black white wire reading on stater side (i think) meter goes complete across to "0". when I checked the other side of the wire, reading was about 750
Customer: replied 1 year ago.
I think i see your replies...i responded ......?
Customer: replied 1 year ago.
Disconnect black/white. On the stator side of the wire. Measure between black/white and a good engine ground. What do you get for a resistance reading?this was your last reply
Expert:  Jason replied 1 year ago.
Just to confirm, from black/white to ground reads zero, correct? What you are measuring is the wire that goes to the stator, and not the one that goes to the switchbox.
Customer: replied 1 year ago.
does ignition key need to be turned on when doing any of these tests?
Customer: replied 1 year ago.
Yes black/white wire from stater, testing with meter.....resistance......analog meter needle travels complete across face of meter to "0"
Expert:  Jason replied 1 year ago.
Nothing needs to be on. And no battery needs to be connected. All you are doing is resistance measurments.
If you are positive on the reading you got and you are comfortable that you are using your meter the correct way then you would have a bad stator. The reading should be in the ballpark of 120 to 180 ohms.
Customer: replied 1 year ago.
meter setting RX100, the "zero" i am telling you is the ohms
Customer: replied 1 year ago.
I changed meter setting setting to Rx1, retested blak/white, and indeed got a reading of 150
Expert:  Jason replied 1 year ago.
Okay, step 2 is black/yellow to ground. Set your meter to Rx100
Customer: replied 1 year ago.
ok, there are 2 black/yellow wires.....one gets reading of 30 (at RX100), which should be from stator, and the other gets no reading, which should be from trigger
Expert:  Jason replied 1 year ago.
Okay now go between the black/yellow that you got a reading on, and back to black/white. Measure between those 2 wires. What do you get there?
Customer: replied 1 year ago.
ok, black/white to black/yellow, through stator, same reading....30...at RX100
Expert:  Jason replied 1 year ago.
Okay that's all good. Leave your meter on Rx100 and measure between brown/yellow and brown/white. What do you get there.
Customer: replied 1 year ago.
about 7.5
Expert:  Jason replied 1 year ago.
Okay, here is where you stand so far. There are 5 parts to the ignition system. The stator, the trigger, the switchbox, the ignition coils and the stop circuit.
The stop circuit is fine as we disconnected it and it still did not work.
It looks like you have 1 bad ignition coil.
The stator and trigger tests were both a pass.
On the switchbox, switch boxes are not directly testable, so what you do is test around them. Which we did. Since everything else is a pass, that leaves you with a bad switchbox. And 1 bad coil. The bad coil might start firing when you get a new switchbox installed, but even if it does, it will likely fail pretty soon.
I do want to make sure you are happy with the service I am providing to you before you do the rating. Did you have any other questions on the ignition issue or do you think that covers it? -Jason
Customer: replied 1 year ago.
our testing told us one ignition coil was bad, if we replaced it without replacing the switch box, and it worked, would that be enough?
Expert:  Jason replied 1 year ago.
Hmmmm.... The engine does not have spark on either cylinder, either coil, correct?
Customer: replied 1 year ago.
correct...no spark either coil
Expert:  Jason replied 1 year ago.
You could have 2 bad coils and a bad switch box, but that it not very likely. However when the switchboxes go bad you will not get spark from either coil. Does that make sense?
Based on all the readings we took today, I would order 1 switchbox and 1 ignition coil. That is what I would do.
Did you have any further questions about this?
Customer: replied 1 year ago.
OK. Thank you. No further question except, can or do we follow up with you when we replace parts or fix the problem?
Expert:  Jason replied 1 year ago.
Yes you can, that's no problem.
Just incase you do not understand the way the website works (and some folks do not). You do have to put forth a positive rating in order for it to credit me for helping you. When ratings are not done, the website simply keeps your deposit and they will not credit me. Please let me know if you run into any problems or errors when trying to do it. If you can not see the ratings box, please reply back "I rate Jason's service as _______" and fill the blank with whatever you deem most appropriate. Questions do not close out, so if you have to come back tomorrow or next week with follow up questions to this you still can even after doing a rating. Tips are always greatly appreciated.
If I do not hear back from you I thank you in advance and good luck!
Jason
Expert:  Jason replied 1 year ago.
Hello, just checking in. Any luck?

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