Spark Plug Wires for 1979 Mercruiser 260 Mallory Ignition

[iaboat]

Hi,

I have a 1979 mcm260 engine with a mallory ignition, serial number 5377242. I'm doing a much needed tuneup but I can't seem to find the right part numbers to get the spark plug wires I need. Everything I see is for thunderbolt ignitions...I called west marine and my local mercury dealer and they couldn't figure out the part numbers. Does anyone know where I can find a kit? I'm trying to get this done for the weekend...any help would be greatly appreciated :joyous:. I've searched this to death. I think these might work but I'm not sure: https://www.amazon.com/Sierra-18-88...rra+18+8803+2&qid=1563816912&s=gateway&sr=8-1

 

[Bt Doctur]

Does you dist cap have posts or holes

 

[Bt Doctur]

T-Bolt typr

non T-Bolt

 

[alldodge]

Have to agree with you, there is no listing.
Might have to go with you make plug wire set. Can get one for a BBC because wires will be longer, and cut to fit. Have to look close for Mallory type cap (ones with holes)

Could also change distributor and use a newer style set

 

[kenny nunez]

Just as A D says get a universal set, NAPA has them. Mallory “YL” is the model most commonly used on marine engines. They are good quality and have ball bearings instead of bushings

 

[iaboat]

Thanks for the replies, I have the cap with holes (second picture, non t bolt). I managed to dig up this doc from the internet. It shows two different parts, one says it's for thunderbolt and the other doesn't say. The non thunderbolt part number is 18-8803-01, and the part I linked to is 18-8803-02. I'm hoping this number just refers to a revision or something and is basically the same part. Someone in the comments also said it doesn't work with the cap with posts, so I'm guessing it works with the cap with holes.

Is this a, if it fits, it will work kind of deal or is there something special about the different wires?

 

[alldodge]

They look correct, and from the Sierra catalog it also confirms the part number 18-8803 (also agree the -02 appears to be revision). Also matches your serial number range

Put the arrow on the wrong line, its the one below it :facepalm: I also checked the boot types in the first pages of the catalog

http://www.sierramarine.com/sierra/2...log.html#p=175

 

[iaboat]

Awesome! Thanks a ton for that info, it looks like I should be good to go. Can't wait to get this boat out on the water this weekend .

 

[iaboat]

So I have another issue. The label for the firing order on the original cap shows the exact opposite firing order of what is in the manual. There is a notch for an index so I know I'm not getting that mixed up. I would assume the manual is correct and I should base it off that, but this makes me nervous. I just bought this boat and it did seem to run ok idling outside the water.

I had it taken to a mercury dealer, he said he wasn't getting full power from a couple cylinders but compression and carb were great so he just recommended a tune up. I would have thought he would have caught it if the firing order was wrong but maybe he looked at the cap and just assumed that was right.

If I try to follow the manual first is there much risk of damage to the engine if it's wrong? Would it even run with the order completely reversed?

 

[Bt Doctur]

The firing order numbers on the cap are correct, 1,8,4,3,6,5,7,2 clockwise. but not necessarily in relation to the notch.
you need to find #1 wire in the cap. facing the motor it the first one on your right 1,3,5,7 on your left is 2,4,6,8

 

[iaboat]

The firing order seems right on the cap, but the labeling of the plug holes appears opposite of the diagram in the manual.
I attached a photo showing how the wires were set up before I touched them. The red numbers I have over the cap matches the numbered holes of the cap's label. I don't think these are right according to the diagram in the manual. Based on the manual I think the wire labeled 4 should actually be where 7 is in my photo, 8 where 5 is, 1 where 6 is, etc.

 

[Scott Danforth]

someone in the past 50 some years pulled the distributor and didnt install it properly. not a big deal, bring the engine to TDC on cylinder 1, and either re-stab your dizzy or index your spark plug wires

as for plug wires, look up volvo or OMC for mallory/prestolite plug wires. all same motor, just a different dizzy

 

[Bt Doctur]

I don't think these are right according to the diagram in the manual. Based on the manual

The wires appear correct, 2,4,6,8 going to the left bank. If your manual has this 1,2,7,5,6,3,4,8 then thats for a reverse rotation motor

 

[alldodge]

Just replace the wires one for one at a time, it will work out

 

[iaboat]

OK, I am going to try finding TDC for cylinder 1 and go from there. Seems like the best place to start.