Merc 9.8 coil

[dajohnson53]

1974 Merc 110 (9.8). I had a bad coil last year and replaced it and it ran fine until recently. Now the other (old) coil seems to be bad, so I wanted to replace it. The current coils are 339-5288. The local Merc parts guy has 339-832757A3 and he says it will work fine. If I want my exactl coil I have to order it and it will be a week or more, plus more expensive. Basically he says all these engines have the same basic coils but the mounting is slightly differnt. They are indeed very similar in size, shape, and have the same connections. You can see photos of both:<br /><br /> My coil <br /><br /> Alternative coil <br /><br />What you can't see on the photo of "my coil" is a tiny (what I think is a grounding) wire - which my parts guy says has the equivalent function to the blade shaped thing coming off the terminal on the "alternative".<br /><br />I can definitely make it fit into my engine's coil mounting brackets. They are that similar in size and shape.<br /><br />Does anyone know if these coils are indeed interchangable (except for the slight variation in the way they are mounted). If the engine indeed runs well with this coil, is there any chance I can damage the engine? I'm especially concerned about somehow making too hot of a spark and/or damaging the switchbox ($$$). I don't know how to find and compare specs on this sort of stuff.<br /><br />Thanks for any help you can give.

 

[Laddies]

Re: Merc 9.8 coil

The right part number for the replacement part is 339-5288T2. When in doubt on part numbers goto BAM Marine.com

 

[dajohnson53]

Re: Merc 9.8 coil

Thanks Laddies. I should have mentioned that I know that the correct current part number is 339-5288T2 (that is actually the one I showed with "my coil" link above). My question is: will that other coil 339-832757A3 (aka "alternative coil" in link above) work and will it harm my engine. I can get it locally today while I have to wait a week or more to get the other. 339-832757A3 will fit the engine, I'm wondering if there's any harm using it.<br /><br />Thanks again.

 

[joblo33]

Re: Merc 9.8 coil

It should be fine, a coil's a coil. I've even used J/E coils for testing purposes on Mercs before. That looks like the standard merc coil with just the peice of metal instead of the wire to ground it. That should fit as long as it's the right size and not the bigger coil off the late 60's inlines, I can't tell from the pic.<br />Eric

 

[dajohnson53]

Re: Merc 9.8 coil

Both coils I'm looking at seem to be apply to "many models" from the early 70s to present. Neither is from an 60s inline. They are virtually identical in size and shape and the connections are identical. Either will physically fit my engine.

 

[Laddies]

Re: Merc 9.8 coil

The 2 coils are not interchangeable. If they were Mercury would not manufacture 2 coils. Coils are not interchangeable in cases that call for differant specs. it's one thing for test purposes and anouther to expect a ignition system to hold up with mismatched parts. Why anyone would give advice like that amazes me, but I guess it's free.

 

[dajohnson53]

Re: Merc 9.8 coil

Thanks - Frankly, the shop in question has not earned my blind faith. This isn't the first issue that seemed a little flakey to me. I appreciate your advice and will just go ahead and get the spec'd part.<br /><br />On a related issue, do you know where a person could find actual specs on parts like this? Thanks.

 

[Laddies]

Re: Merc 9.8 coil

The main differance in electrical parts like coils or in this I belive a transformer (AC would make it a transformer) is in the winding resistance Which in some cases is measured in OHM with a meter or input/output like a coil tester does, in either case most good service manuals will list the values of each part by part number or year.

 

[dajohnson53]

Re: Merc 9.8 coil

Thanks once again.