Coil problems

[Golfdad75]

Coil questions

Ken at Moyer Marine recommends a coil between 3.5 and 4.5, perfect would be 4.
I am putting in the PerTronix electronic ignition and they recommend the Flamethrower Coil which is rated at 3.0.

Ken has not ever let me down, however the Pertronix is in the business and they made the system.
Any suggestions

[edwardc]

Add the extra 1 Ohm resistor. You'll be happy you did.

[sastanley]

GolfDad, Ed gave you the short answer, which is perfectly acceptable.

Another alternative is to buy one of the coils that Moyer sells...it is in the range you are looking for.

If you REALLY want to understand it..read this thread, below.

https://www.moyermarine.com/forums/showthread.php?t=5748

[Golfdad75]

Your Right

The people at Moyer Marine are so friendly that I hate not to buy from them. I ordered the coil yesterday.
Two weeks ago I knew nothing about coils.

[ndutton]

Two weeks ago I knew nothing about coils.

And in time you'll be better versed on the intricacies of the Atomic 4 than the vast majority of professional marine mechanics out there.

[hcrisp]

Wrong Information

All too true, Niel. I was just advised by a mechanic that no fuse was necessary if any wire run was shorter than one foot. Egad! Similar experience last week with the manager of the local WestMarine.
Important to stay connected with this forum.
Howard

[ndutton]

But I digress

I was just advised by a mechanic that no fuse was necessary if any wire run was shorter than one foot. Egad! Similar experience last week with the manager of the local WestMarine.

The ABYC allows a length of unprotected (unfused) wiring and depending on certain conditions the length can be 7, 40 or 72 inches. The basic allowance is 7 inches. I believe their reasoning is, "What can go wrong in 7 inches?" (plenty if you ask me). In non-authoritative, seat of the pants, common sense application, unprotected wiring is bad practice period. For Mr. Mechanic, his distance is wrong and his suggestion fusing is unnecessary, unsafe.

As an example of official standards that are often eschewed, the National Electric Code allows wiring of different voltage systems to be placed in the same conduits and junction boxes provided the wire rating meets the highest voltage present. No responsible electrician does that however. 120/208 voltage systems are completely separated from 277/480 systems with their own conduits and boxes. Point being although allowed, true craftsman apply a higher standard. Same with the fusing discussion and the ABYC.

Speaking of "experts", you ought to hear some of the Shinola dispensed by the experts wearing orange aprons in the Home Depot electrical department. Someday they'll kill someone if they haven't already.

[roadnsky]

As an example of official standards that are often eschewed, the National Electric Code allows wiring of different voltage systems to be placed in the same conduits and junction boxes provided the wire rating meets the highest voltage present. No responsible electrician does that however. 120/208 voltage systems are completely separated from 277/480 systems with their own conduits and boxes. Point being although allowed, true craftsman apply a higher standard. Same with the fusing discussion and the ABYC.

A Gold Star for Neil for proper (and timely) use of expanded vocabulary.

[ndutton]

Insider comment for us old timers

That word was branded on my brain a few years ago on this forum, took me out of the running for a free set of spark plugs too. I could have eschewed "eschew" but my strategy is if I use it enough it will become ubiquitous and hopefully level the playing field next time.

Ken at Moyer Marine recommends a coil between 3.5 and 4.5, perfect would be 4.
I am putting in the PerTronix electronic ignition and they recommend the Flamethrower Coil which is rated at 3.0.

Ken has not ever let me down, however Pertronix is in the business and they made the system.
Any suggestions

This is from post #179 of the "Coil Input Information" thread. The basis of the math is Pertronix's own advisement, buried deep in their literature, of a 4 amp system maximum.

If all of us who made the move to EI had only followed Don's advice from February 2005 of a 4 ohm coil, none of this would have happened. None of it.

I used a 3 ohm coil. After all, Pertronix - whose name is on the EI unit - said their coil (3 ohm) was the perfect match to their EI system. Well, it ain't. The math works out at 12 volts but once you consider alternator voltage when the engine is running - somewhere between 13.8 and 14 + volts (less system voltage drop), their math flies out the window.

Using a coil or coil and resistor combination of 4 ohms protects the EI system up to 16 volts. Pertronix won't tell you that (why I don't know) but Don did nearly seven years ago.

The math or alternatively the provided resistor calculator varies because all of us have different voltages at the coil due to differences in wiring systems and their resultant voltage drop and differences in alternator output voltages (the manually adjustable crowd often being the worst offenders). The 4 ohm coil figure works well for those who flunked math.

[warefuller]

Coil failures

Almost all coils are 6-volt coils - they have a low impedance (resistance). If they are run at 12-volts they will get quite hot and eventually fail. Either use a high-resistance coil or add an external resistance (auto parts store) in series with the coil. An even better choice (with a 6-volt coil) is to wire the coil so that it gets 12 volts when the ignition switch is in 'start', and 6 volts when in 'run'.

Ware

(without a silly quotation)

[ndutton]

EWDS reference again

During the EI/coil studies of a few years ago one of our members performed some excellent input voltage testing. Using a 3Ω coil (can't remember the brand he tested) without supplemental external resistance he found that engine performance significantly degraded when coil input voltage dropped below 9 volts. We used his test results when determining the coil voltage parameter trip point for the EWDS.

[67c&ccorv]

Almost all coils are 6-volt coils - they have a low impedance (resistance). If they are run at 12-volts they will get quite hot and eventually fail. Either use a high-resistance coil or add an external resistance (auto parts store) in series with the coil. An even better choice (with a 6-volt coil) is to wire the coil so that it gets 12 volts when the ignition switch is in 'start', and 6 volts when in 'run'.

Ware

(without a silly quotation)

Norton motorcycles used 6 volt coils in their 12 volt systems in order to provide a "hot" spark on startup when voltage was low due to a depleted battery.

A ballast resistor was wired into the system to prevent the coils from overheating and the points from burning once the engine was started and system voltage was up to full value.

[blhickson]

Ginny sounds better, starts better, but...

When I was able to get back to the boat, distinct gas smell and scavenge tube was leaking like a sieve. Got that corrected. Alternator with new voltage regulator and coil measuring 4.2 ohms re-installed. The choke lever needed some adjustment but not much, and I did ensure that the carb throat was open with no choke and closed with choke on. Now, the engine starts better but not great. Even before all this, the engine would start with full choke on the 2nd try and then I could push the choke in very slowly and engine would run.
Now, the choke does not seem to impact how quickly the engine catches and I think if I get the time tomorrow, I will remove the starter and take it to get tested.
In the meantime, last Sunday, the engine did start after about 4 tries with throttle and choke and ran smoothly for about 20 minutes, then died a slow fuel starvation death. This is what has been happening for 2 years. The engine will run as long as I want it to sitting at the dock. It seems like it only dies when its under load in a current or wind.
I'm flummoxed. I am getting a tach tho, but I don't think it has much to do with the rpms of the engine. So, how would the effort put forth by the engine impact a) whether it gets sufficient fuel and/or b) if it can get sufficient spark?
Thanks. Oh, and where does the external resistor go on the coil?

[ndutton]

Two thoughts:

1) Under load the engine uses considerably more fuel so I'd look at fuel delivery (including the fuel tank vent) and the internal carburetor float valve. A fuel pressure gauge would be helpful.

2) How did you determine an external resistor was needed? A 4.2Ω coil with electronic ignition wouldn't need one unless the coil input voltage was over 16.8 volts (or 14.3 volts if you choose to follow the recommended 15% safety factor). The resistor is installed in series with either small wire on the coil. Pertronix's installation instructions shows it on the positive side.

[blhickson]

I will borrow a fuel pressure gauge and check that out. Wouldn't it be easier to check the fuel pressure and see what that says first before taking the carb off to recheck the float? I tested the float in slightly heated water when I rebuilt it and no leaks. When I reassembled it I made very sure that it was level with the body but at that time knew nothing about the specific clearance. The carb is a devil to get to.
Re: the fuel vent. When running engine out in current/wind and it begins to exhibit the usual symptoms, I have cracked the gas filler cap and it does allow it to run a bit longer, one time quite a few minutes longer. Now that I think about it, that time was at slack tide too. I have checked the vent line for obstructions and I will check again. <sigh>
I was really just curious about the resistor but thank you. And thank you very much for your help. I'm checking the starter and solenoid as the batteries are new and should not be any cause for starter issues. May seem like a lot going on but it's really not. Just ruling stuff out (like the faulty voltage regulator!).