Mismatched Ignition Coils - Which Color Should They Be?

scout-j-m

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Guys, I have a 1994 70hp Force. The attached pics show the three ignition coils currently on there. I experienced some high rpm running problems last fall which I never fixed and I have yet to get on the water since then. The 2 lower coils are blue and the top one is black. The black one also has what appears to be electrical tape on it for some reason (???). Anyways, I figured I'd go ahead and get a replacement for the taped up one since it is the odd one out.

The question is:
1.) Should the coils be blue or black for my year and model?
2.) When I order the replacement coil will it be a blue or a black (I order most of my parts from boats.net. The part # listed by them for the coil is
7370A23.)


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jerryjerry05

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Re: Mismatched Ignition Coils - Which Color Should They Be?

Looks like the same coil just has tape.Do a spark gap test and see if it's performing.Might save you some $$$ J
 

roscoe

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Re: Mismatched Ignition Coils - Which Color Should They Be?

Hmmm, again I am the bearer of bad news.

I don't believe you have a 1994 model.
They stopped using the 2 stage fuel pump shown in your photo, the last model to use that pump was the 1992C.

The current coil replacement number from Mercury is 339 - 832757
Should be able to get one from any Merc dealer like dougrussell.com for about $35

My 70 hp had the dark blue coils, I believe the black one is the one that doesn't belong.

Can check the year of the motor with the serial number.
 

scout-j-m

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Re: Mismatched Ignition Coils - Which Color Should They Be?

Looks like the same coil just has tape.Do a spark gap test and see if it's performing.Might save you some $$$ J

jerry, it probably is working fine but it strikes me as odd that it isn't like the others. My reasoning for suspecting it also it the way the motor was permorfing the last few times I used it. What would happen is the motor would start and idle fine, then I would shift into forward idle and make my way out from the ramp with no problem. I'd get on the throttle, get up on plane and cruise smoothly with good speed. The problem was after a few minutes the motor would begin to surge, kind of like riding a 4-wheeler and repeatedly hitting and then letting off the gas. I thought it was fuel related but everything checks out from the tank to the carb plus the motor stalled out or anything. I mean it seemed like I could run it full throttle like that I would just not be going nearly as fast. It led me to believe that that jacked up looking coil was possibly failing by overheating or something.
 

scout-j-m

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Re: Mismatched Ignition Coils - Which Color Should They Be?

I don't believe you have a 1994 model.
They stopped using the 2 stage fuel pump shown in your photo, the last model to use that pump was the 1992C.

I will do that. I know the motor tag says it a 94 but I don't have the serial number on hand. How did they code the serial numbers for these motors? Did certain numbers mean certain things as in 0-9 of the first digit meant x or did they sequentially do this number range for a 92, another range for 93, etc?

Also, serial number aside, do you recomend replacing that coil if simply not the fact that it doesn't belong?
 

scout-j-m

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Re: Mismatched Ignition Coils - Which Color Should They Be?

I don't believe you have a 1994 model.
They stopped using the 2 stage fuel pump shown in your photo, the last model to use that pump was the 1992C.

Roscoe, I looked on my bookmarked page from boats.net. You are right, the 2 stage pump is only on models 91B -92C. However, I did notice that the 2 stage as well as the square type fuel pumps have what appears to be the same gasket where they mount to the engine. Does the squre type use the pressure changes from the crank like the 2 stage does? If so, I figure they could have been swapped at some point in time or another.

2 stage:
http://www.boats.net/parts/search/M.../FUEL PUMP ASSEMBLY (91B THRU 92C)/parts.html

square type
http://www.boats.net/parts/search/M...1 THRU 0E138599/FUEL PUMP ASSEMBLY/parts.html
 

scout-j-m

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Re: Mismatched Ignition Coils - Which Color Should They Be?

I clicked on the 2 stage pump kit description on the link for the 2 stage pump and it listed the years and models it went with. According to boats.net's list, the 1994 70hp had many different models, some of which did have a 2 stage pump. I guess they could be wrong. I'll make sure to look at my serial number tonight though.
 

roscoe

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Re: Mismatched Ignition Coils - Which Color Should They Be?

Mercury sold all 70hp models after the 92C, with the square fuel pump yeah someone could have changed it.

The coil does not look right to me, at least the plug wire doesn't.
I think they cobbled it together. What were they hiding with the tape?
Bet there is a crack in the coil case.

It looks like the old black coils from the mid 80's Force motors.
 

scout-j-m

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Re: Mismatched Ignition Coils - Which Color Should They Be?

I looked and the serial number is OE064766.

I'm also going to take the boat out today and see if it gives me the fits I described to jerry a few posts up. If it does, I think I will just pull that plug wire from the susceptible coil. Hopefully, the motor will only lose power but quit the surging thing it was doing.
 

roscoe

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Re: Mismatched Ignition Coils - Which Color Should They Be?

Well, that serial number looks like it is for a 94 model.

Let us know what you find.
 

maxum_man

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Re: Mismatched Ignition Coils - Which Color Should They Be?

About the "surging" problem...I had the same thing on a 25 hp evinrude. Is your motor the original on the boat? I had a long shaft motor on a VERY tall transom and the Cavitation plate on the motor was a little too high. Luckily, this was an inexpensive jon boat that I took a Sawzall to and made the transom 1.5" shorter! Just might check that aspect of it!

Bryan
 

scout-j-m

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Re: Mismatched Ignition Coils - Which Color Should They Be?

Roscoe, Thanks for the verification on the year. I really appreciate it as well as all of other advice. You have helped me out tremendously.

Bryan, thanks for the advice as well. It turned out the surging was due to a fuel related problem and not the coil. I don't exactly know what the problem was, but I ran a can of Seafoam through the tank and it quit doing it after about 20 minutes of riding around. It runs wide open smoothly now but it misses out a little and is making some odd noises. The carb definatley needs cleaning and I still plan on getting a new coil. I also really need to get my tach working. It would be helpfull to have for all the test runs I'm having to make!:)
 
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