1980 Mercury 115HP No Fire Cyl 2,5,6

[davidsa]

New owner of a 1980 Mercury L6 with no fire on cylinders 2,5&6. I bought a repair manual and all ohlm meter test check out OK (Stator, Trigger, Ignition Coils). The book does say I would need a Quicksilver Thunderbolt Ignition Analyzer to fully check the switch box and ignition coils. Any ideas of what my next step should be. My closest Mercury Dealer is 1 hour away. THANK YOU!!!

 

[Valv]

Re: 1980 Mercury 115HP No Fire Cyl 2,5,6

I am not an expert, but I had mine '79 140hp 6 inline doing same thing. I ended up replacing the CDI box. Unfortunately since CDI has different ROM than Mercury you have to replace the other one also, even if it's good. That was not cheap, but now runs like a champ.

 

[12Footer]

Re: 1980 Mercury 115HP No Fire Cyl 2,5,6

I agree with valv. It is the most common failure (at least from what I have read here,and from the two I personally messed with).<br />Before changing it tho, start it up at night, and make sure the plug wires aren't arcing to ground. It will be visable in darkness.

 

[Bruno]

Re: 1980 Mercury 115HP No Fire Cyl 2,5,6

I spent over $1500 on assorted parts trying to get a bog sorted out on my 86 115 Mariner(same thing),and to not get into a long story,the cdi packs(one original and one sierra because of a back order on original)ignition trigger,and part of a rebuild kit because I was told I had a cracked reed(Marine mechanics around here are REAL smart in diagnostics,...huh!)are not returnable.It's too bad you don't live closer or you could try everything I have to see what is wrong ,like the marinas here made me do.It might even get my garage a little cleaner (Grin)

 

[davidsa]

Re: 1980 Mercury 115HP No Fire Cyl 2,5,6

Thanks for the help guys. Earlier when I checked the spark I switched plug wires 4 & 5 and still didn't get spark on 5 but still had it on 4. What is meant by Valv saying, "I ended up replacing the CDI box. Unfortunately since CDI has different ROM than Mercury you have to replace the other one also, even if it's good."? Is the CDI box above refering to the switch box? What is meant by ROM? I'm new to boat motors which I agree is probably 99% of my problem. Thanks for the patience!

 

[Bobby Powell]

Re: 1980 Mercury 115HP No Fire Cyl 2,5,6

Yes I beleive there CDI box is referring to your Mercury switch box. the upper switch box controls cylnders 1,3,5 and lower controls 2,4,6. Try swapping switch boxes to see if problem follows the switch boxes. If not then may be coil or corrided connections, if the problem follows then welcome to my world and dish out money for switchboxes. <br /><br />I am really poor...(boat budget wise) so I bought used ones, had to return one switchbox because #3 would not fire but after exchange it idles great...have not put in water yet.<br /><br />These are my recomendations and anyone can correct me (J.B., fone-man, oddd1, etc) as I am still new to the boating world.<br /><br />G-luck-<br />Bobby

 

[Valv]

Re: 1980 Mercury 115HP No Fire Cyl 2,5,6

Davidsa, the original CDI boxes are from Mercury. I replaced mine with Reapair (spelled right ??) which have a ROM (small chip with all informations inside, kinda a small computer chip) that is different from Mercury. They suggested replacing both, since it could create problems or damage one of the 2 being different.<br />The suggestion to swap boxes before buying is perfect and I actually did it too (but I forgot to mention it). I purchased mine here in Minneapolis, and if you need a good marine parts shop with excellent prices I can send you the phone #, since you are in IA, and shipping shouldn't be too much. Once you tried other box and find out if it works, you should be 100% shure of problem.<br /><br />Bobby Powell....when it's about boat repair....WE ARE ALL POOR, OR GOING TO BE!!! I bought mine refurbished also.....

 

[Valv]

Re: 1980 Mercury 115HP No Fire Cyl 2,5,6

Geee, I just noticed.....I am Captain ???<br /><br />Man, I just posted 4 or 5 postings and I get nice rankings....I like this site. I'll have to go buy a Captain's Hat now..

 

[ODDD1]

Re: 1980 Mercury 115HP No Fire Cyl 2,5,6

David, from what you have for a failure, I would think you have more than one component failed....the shotgun approach of tossing parts at it will get expensive an fustrating....get the equipment and manuals to troubleshoot it properly, or head for the dealer....

 

[Valv]

Re: 1980 Mercury 115HP No Fire Cyl 2,5,6

Davidsa, I found some switchboxes on Ebay.<br /><br />Follow link:<br /> http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=1181143250 <br /><br />and<br /> http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=1181126825 <br /><br />I asked seller if they come from same motor and I am waiting for answer. <br /><br />It might be a cheap solution to your problem.<br /><br />Val