50 hp mercury, 2 stroke. No spark from cylinder 2

[Capt dave 258]

Recently picked up a very clean 1982 Mercury, 50 hp. Compression test is about 150 in all 4 cylinders. Put it in the lake today for the 1st time and it had intermittent power, never getting on plane. Brought it home and ran it with muffs. Removed coil wires one at a time and noticed no difference with #2 coil wire removed; couldn't hear a spark when removing the wire and no difference in rpm's. Tested all 4 coils and they all fell within the acceptable range. Switched plugs around from cyl 1 and 2 and still no spark in cyl 2. Checked resistance on #2 coil wire and it was fine. Checked the wires from the cdi for cyl 2 and resistance was fine on those. I'm thinking it's the cdi and don't mind spending the money if that's the problem. Is there someway I can test the cdi to determine if that's the issue? Is there something else I should be looking at? Any help is appreciated.

 

[richw46]

Have you switched the CDI between the cylinders to see if the problem follows to the other cylinder?

 

[Faztbullet]

Switchbox....use OEM only

 

[richw46]

Switchbox....use OEM only

I couldn't find a Mercury switchbox for my 95 115. I found other manufactured versions but not OEM. I went with CDI electronics and it is working fine, wasn't expensive, $36 on Amazon. Mercury suggests you replace both switchbox and stator at the same time because if one goes bad it can damage the other. My stator was bad, replaced both, later, I rolled the dice, went back to OEM switchbox and everything is working.

OP thinks the CDI might be bad. I have experience only with my motor and it has coils, not CDM (later models had CDM). I'm wondering if OP means CDM instead of CDI. He says coils test okay but I didn't think you'd have both coils and CDM/CDI. Maybe he means switchbox???

 

[flyingscott]

I couldn't find a Mercury switchbox for my 95 115. I found other manufactured versions but not OEM. I went with CDI electronics and it is working fine, wasn't expensive, $36 on Amazon. Mercury suggests you replace both switchbox and stator at the same time because if one goes bad it can damage the other. My stator was bad, replaced both, later, I rolled the dice, went back to OEM switchbox and everything is working.

OP thinks the CDI might be bad. I have experience only with my motor and it has coils, not CDM (later models had CDM). I'm wondering if OP means CDM instead of CDI. He says coils test okay but I didn't think you'd have both coils and CDM/CDI. Maybe he means switchbox???

The OP would have a CDI/switchbox coil set up. CDI and Switchbox are the exact same thing. Where are you getting CDMs from?

 

[richw46]

At the Mercury online parts manual for my engine. If I check the early serial numbers I see coils. If I look at the later numbers I see CDMs

 

[richw46]

The OP would have a CDI/switchbox coil set up. CDI and Switchbox are the exact same thing. Where are you getting CDMs from?

I have heard switchbox and power pack were the same but not CDI. The only CDI I've heard of is the company that sells CDI switchboxes for Mercurys.

As I said earlier, I'm not familiar with much more than my 95 115. Just offering my 2¢

 

[flyingscott]

CDI is what OMC calls their switch boxes. Mercury just calls them switch boxes. Same thing different name. CDI is not a brand name. CDI electronics used to be called Rapaired. So something happend and they just changed their name to CDI electronics. CDM modules are altogether different.

 

[flyingscott]

At the Mercury online parts manual for my engine. If I check the early serial numbers I see coils. If I look at the later numbers I see CDMs
View attachment 390352View attachment 390351

What does your engine have to do with anything? Op clearly stated he has a 1982 motor.

 

[richw46]

What does your engine have to do with anything? Op clearly stated he has a 1982 motor.

Just trying to help. Why are you attacking me?

 

[flyingscott]

So you feel attacked because I corrected what you said? Then I explained the difference to you and you feel attacked? Then I ask you what your motor has to do with the OPs because you have a 95 115 and the OP has an 82 50 hp. and you feel attacked. I did not see the commonality between those 2 motors so I asked a question. big boy pants people