Eska 7.5hp ignition coil retrofit

[Tommy Two Stroke]

I wanted to share the mechanical details of my recently completed retrofit of a Sierra 18-5176 OMC style ignition coil to an Eska 7.5hp outboard, in case anyone could use this info. This outboard has the infamous under-flywheel solid state trigger module and the no longer available ignition coil mounted to the gas tank. The pics show the box beam stock that I fashioned into a bracket to accept the Sierra coil. Nuts for the coil attaching screws are epoxied to the inside of the bracket for captivation. The bracket is held to the gas tank with screws, and I had to drill one additional hole in the tank and enlarge one of the holes that was used to mount the old coil. Bottom line: if you have one of these outboards with a failed original coil, it is possible to retrofit a widely available Sierra 18-5176 coil to the outboard using this method.

 

[mrcrabs]

Re: Eska 7.5hp ignition coil retrofit

Pulse tranformers, "coils" were also mounted forward beneath the stator plate on the tankless shroud models, every 640 tecumseh I have seen have had the mounting holes machined there. If someone has a tankless engine shroud the OMC coil will be a little tougher to mount.

 

[sizemoremk]

Re: Eska 7.5hp ignition coil retrofit

Hello, I would like ot do the same swap, according to the data I can find on my model number for my 1973 model, mine takes the external 610785A transformer, and the 610851A magneto unit. Do you know if yours was the same origional part number?

Also, it is unclear in the picture, but I am assuming you have one lead for the trigger, and the other wire is ground?

Thank ya sir!

 

[mrcrabs]

Re: Eska 7.5hp ignition coil retrofit

Tommy is a zin master he only comes buy when he makes a new, old discovery....yes it will work for you based on your ignition model numbers. there are other coils that will work as a pulse transformer as well.

 

[Tommy Two Stroke]

Re: Eska 7.5hp ignition coil retrofit

sizemoremk, the OMC style coil I used has both a ground lead and a trigger lead. Most pics of that particular coil show the ground lead to be black and the trigger lead to be orange

mrcrabs is right, I'm usually only on the forum when I have some retrofit info to share, but I do browse it on occasion

 

[Tommy Two Stroke]

Re: Eska 7.5hp ignition coil retrofit

mrcrabs, I'm about to do an OMC coil conversion on an ESKA 9.9....just picked up this engine over the weekend, my first 2-cylinder ESKA. I'm going to have to figure out how to mount two OMC coils this time around. Stay tuned.

 

[Eska1969]

Re: Eska 7.5hp ignition coil retrofit

I have an 7 hp Eska 1707 solid state with the external 610785B pulse transformer and the 610851B magneto unit under the flywheel that will not start and was wondering if your OMC retrofit will work on it? If so, how do I do it? What gets hooked into what and what do you do with the existing magneto, trigger assembly and how does it fit with the flywheel? Please advise. Thanks so much.

 

[mikeAZ]

Re: Eska 7.5hp ignition coil retrofit

I've also done this with the info from here. I don't have a mill so I just used 2each 3/4 o.d. x 1/2" long plastic stand offs from the hardware store. I drilled and tapped the tank bracket 1/4"x20 tpi x 1 3/8th long bolt & a little blue lock tite ... Runs fine now!

 

[Tommy Two Stroke]

Re: Eska 7.5hp ignition coil retrofit

I have an 7 hp Eska 1707 solid state with the external 610785B pulse transformer and the 610851B magneto unit under the flywheel that will not start and was wondering if your OMC retrofit will work on it? If so, how do I do it? What gets hooked into what and what do you do with the existing magneto, trigger assembly and how does it fit with the flywheel? Please advise. Thanks so much.

The existing trigger unit under the flywheel stays in place, and nothing changes with the flywheel. The output from the trigger unit goes to the input (orange) lead of the OMC coil. Make sure the trigger unit is good though, because replacing the coil with the OMC coil the way I did it will only work if your trigger unit is good. The black lead on the OMC coil goes to ground.

 

[pellasaws]

Re: Eska 7.5hp ignition coil retrofit

theres many types of ignition parts that will work to replace the transformers

 

[mrcrabs]

Re: Eska 7.5hp ignition coil retrofit

Hello pellasaws, AKA my Ole buddy Eskaman2008, how is tricks?

 

[nwcove]

Re: Eska 7.5hp ignition coil retrofit

gotto love good ol "enginenuity!!"

 

[sgtballjoint]

Re: Eska 7.5hp ignition coil retrofit

thank you all for the info. i have a 1977 7.5hp . it shut off in the middle of the river, had to get towed , thanks to a fellow fisherman. Found there was no spark/wet plug. i read this thread earlier today, i did find a 610785B on the web for $100. but with this info im much happier paying $30. Thanks again

 

[farmboy917]

Re: Eska 7.5hp ignition coil retrofit

Hi i have a eska model 217-58880 an im having firing problems . Im not sure what size this is also, any info would help thanks

 

[najwater]

Re: Eska 7.5hp ignition coil retrofit

I wanted to share the mechanical details of my recently completed retrofit of a Sierra 18-5176 OMC style ignition coil to an Eska 7.5hp outboard, in case anyone could use this info. This outboard has the infamous under-flywheel solid state trigger module and the no longer available ignition coil mounted to the gas tank. The pics show the box beam stock that I fashioned into a bracket to accept the Sierra coil. Nuts for the coil attaching screws are epoxied to the inside of the bracket for captivation. The bracket is held to the gas tank with screws, and I had to drill one additional hole in the tank and enlarge one of the holes that was used to mount the old coil. Bottom line: if you have one of these outboards with a failed original coil, it is possible to retrofit a widely available Sierra 18-5176 coil to the outboard using this method.

This is exactly what I am looking for! My '76 7.5 has a bad coil and of course I am unable to find an NOS part. Do I need to use a coil with very similar primary and secondary resistance values so I don't overheat or some how damage my cdi/trigger unit? Thank you for a very good post!!!!!

 

[ballhwk2001]

Re: Eska 7.5hp ignition coil retrofit

this post solved my problem, thank you so much. just to give you guys a heads up. i manage a napa auto parts store in wv. i crossed the sierra oem number to an echlin and its available all over the warehouses. part number ECH IC700. just to help you guys out. instead of waiting for it to arrive. just drive down to napa. thanks again tommy!

 

[phrozin]

Re: Eska 7.5hp ignition coil retrofit

dont understand what the orange lead would connect to? make a barrel splice from the existing lead wire from the coil under the flywheel to the new orange lead wire?

 

[scsulliv]

Re: Eska 7.5hp ignition coil retrofit

I know this is an old thread, but it's still great advice for keeping these old engines running. I just ordered the Sierra coil for my Ted Williams 7.5hp, model # 217. Very nice job making up that adapter bracket, too - I'll use that as a template!

Thanks again, guys!