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Merc 75 ran greatI came back from vacation and it had no spark

krider

New member
"I have an older Merc 7.5 ser

"I have an older Merc 7.5 ser #3104046 So I've checked the kill switch - grounded unless pressed - working fine. Check, removed, cleaned the points. Reinstalled them with a .020 gap. With a meter I found that they were opposingly grounding and ungrounding the coils. I cleaned the stator surfaces. Also cleaned all wire connections to the coils. Oh and obviously installed new plugs. Still no spark. That leaves the stator and the coils. Well it is unlikely that both coils would go at once. So I'm guessing its the stator. I've tried to see if I get any juice out of the stator but am not really sure if I am testing it correctly. I found a part on this site that looks exactly like my stator but I am unsure if there are certain model years that this part fits. This is the part number "18-5855". I am not sure if I want to put $300.00 into this motor. Before this "breakdown" the engine was running great. First pull starts! Should I check anything else? I've scanned through previous posts but I didn’t find anything on this subject. I hope its not a repeat post."
 
"Kevin, that's a 71 model.

"Kevin, that's a 71 model..

Anyhow, sounds like you have an ohm meter so you can do a test on the stator to see if that's the issue.

Basic stator test as follows: (ohm meter set to Rx1000) - disconnect the the green and salmon stator wires from their terminal points

positive to Green lead
negative to Salmon lead = no continuity

Reverse of above = 20-50 ohms

positive to Green lead
negative to ground (engine block) = no continuity

Reverse of above = no continuity

Merc part numbers for the stator are 336-3996A4 supreseded to 336-3996A7. The part number you list looks like a sierra number(?) which could possibly be cross refd to one of the above. The Merc part (still available) goes for a little over 350 bucks.

And I do tend to agree with you, I'm not sure I would put that much into the motor - for an extra couple hundred bucks you could pick up an mid 1980's 8 horse (or even a 9.9), with modern ignition.

However, these motors were popular and you may be able to find a used stator (if that's the problem) at a parts recycler or Ebay (or the like)..."
 
I finally got some time to che

I finally got some time to check out the stator as you described in your post. It looks like I have no resistance when checking the negative to green lead and the positive to salmon lead. Must be a diode that went bad in the epoxy sealed pack on the stator. I looked around for a used stator but didn’t really find one. Finally found a company in CT that specializes in older engines. They found a CDI stator for about $250.00 new. They shipped it out to me today. I should have it by Thursday. Thanks for all the help Graham. I really appreciate it.
 
"*"I found a part on t

"*"I found a part on this site that looks exactly like my stator but I am unsure if there are certain model years that this part fits. This is the part number "18-5855". I am not sure if I want to put $300.00 into this motor."*


This is the one I found on this site originally. I didn’t see that the one you posted replaces this older unit


http://www.marineengine.com/newparts/part_details.php?pnum=SIE18-5855&ptype=&Eng ine=&Model="
 
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