coil question

Engines, Shafts, Steering, Struts, Rudders, etc.
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tjc7t7
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Joined: Sun Mar 01, 2015 7:54 pm

coil question

Post by tjc7t7 »

i was reading old post about orange spark and the problem with it. my 84 318 will crank but wont start i changed the coil and resistor and the ecu was replaced mid season last year. i read were fast jeff used a mallory 700 ballast resistor and an accel 8145 output coil. is this also goood for a 318 and is there any other changes that need to be made to handle the increased voltage? This problem is driving me crazy and i dont want to cause any more problems be upgrading only half the system. thanks!
1984 28 Express hardtop single 318. Lake Erie Jefferson Ohio
DougDoty
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Re: coil question

Post by DougDoty »

Jeff is known on the forum for giving solid and personally tested advice, so to answer your question, yes !!
1984 39 Marinette Sedan, " LIBERTY ONE " Warsaw KY, 440 chryslers, Westerbeke 9.0 kw , 1 3/8" shafts 93 1/4" long and 19x22 dyna quads or, 19x20 DQX's 38.5 MPH GPS best.
Fastjeff
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Re: coil question

Post by Fastjeff »

Well!

The trick is to use a 12 volt, high performance coil that does not require a ballast resistor, WITH a ballast resistor. That keeps the amperage flow down (and, if you accidentally leave the ignition on, saves the coil. Ah-hem!) Summit Racing or Jeggs sells economy high voltage coils that work just fine. And they will work for any size engine (ie: the 3.6 Merc outboard I once worked on needs the same ignition clout as the 150 hp. monster).

Jeff
"We live at the bottom of an ocean of air, not at the top." General Marvage Slatington
tjc7t7
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Re: coil question

Post by tjc7t7 »

thanks for the info! The manual for the engine states to use a .5 and 5 ohm dual resistor. what is in the boat and all i can find is a 1.2 and 5. is this a problem? I plan on switching out the coil as previously recommended but i want to make sure i have the correct resistor? The one i currently have is a 4 pin and the mallory 700 is only two? I was reading that i can switch out the ecu to a four pin and use the two pin resistor? and if so what do i do with the other two wires. thanks again for the help the info on this site is priceless!!!
1984 28 Express hardtop single 318. Lake Erie Jefferson Ohio
ericinga
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Location: Cumming, GA

Re: coil question

Post by ericinga »

I'll try to post a pic of this setup.

Here's what I did:
1. Remove ballast resistor.
2. Use two barrel connectors and bypass the resistor e.g. connect top connections together and bottom connections together.
3. Install new coil.
4. Mount the Mallory resistor near the coil. I put it near the coil for ease of testing and maintenance.
5. On the hot side of coil (12 volts coming in) snip the wire and connect the Mallory 700 resistor.

You're done. Really simple and effective.

Eric
Eric Spies
1989 32 SDFB
Twin 318s
Lake Lanier, GA
Marinette Boat
Fastjeff
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Re: coil question

Post by Fastjeff »

Hold it! You MUST use a resistor to power the ECU (it doesn't like full voltage) or they will eventually fail. I made that mistake and had to replace both of them.

The factory ballast resistor has two circuits that the egghead engineers (over engineering engineers) designed to power the ECU. Later ECU modules have only 4 (vs 5) pins, so the engineers finally smarted up and went with one resistor circuit. (Either ECU is interchangeable.) BUT you MUST run lower vltage to the ECU or it will fry! Took mine a year or so, but poof!

Jeff

PS: NAPA (and others) sell a resistor that allows the wires to be BOLTED on (vs. spade connections). Much better design. Had that factory connection fall off on me once; had a merry time understanding why the motor would start, then stall soon as I took my fat fingers off the starter switch.
"We live at the bottom of an ocean of air, not at the top." General Marvage Slatington
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