ignition coils are they either good or bad or can it be weak

[nailem]

Just as the topic reads. is an ignition coil either good or bad or can it be weak?

boat is running good but i am a fan of keeping up on maintenance items. i also am a fan of saving my money. so i have replaced the cap, rotor, plugs/wires. should i replace the coil or if it works its fine?
thanks

 

[Maclin]

Re: ignition coils are they either good or bad or can it be weak

They won't weaken over time. If your engine is running good at idle and thru the rpm range then relax. Even then, if you have problems it is probably not the coil. I'm just sayin'....

 

[JustJason]

Re: ignition coils are they either good or bad or can it be weak

I disagree... they can become weak over time. And they can certainly breakdown and not make enough voltage at close to WOT rpms to maintain spark.
But if you have no WOT issues... then it's fine.

 

[nailem]

Re: ignition coils are they either good or bad or can it be weak

thanks for the reply.

i have been fighting a prop/rpm issue. i have a 1986 sunrunner 220cv with a 5.0L alpha 1 gen 1. boat came with a 21p and would hardly plane, spare prop was a 17p which was better but still only hit 4000prm@WOT so i bought a 15p 4 blade and for the most part i am happy. planes off quickly but rpm is still only 4500-4600rpm@WOT verified with digital tach. it is just a family boat so it is not like i need the speed it just bothers me why i need such a short pitch. everyone in the prop section say i should be able to run a 19p.

so maybe a coil is worth a try????? anyone else.

 

[mmccoy555]

Re: ignition coils are they either good or bad or can it be weak

The coil can become weak but that usually means that it's in the process of becoming bad. Replace.

 

[JustJason]

Re: ignition coils are they either good or bad or can it be weak

when was the last time you had a full tune up?

 

[Maclin]

Re: ignition coils are they either good or bad or can it be weak

Most of them do not age, as in get weaker and weaker. When they fail it is more like an immediate attenuation in their output and they will yield weak or no spark. They are deemed "bad" by then, and it is not usually a gradual thing. Most are fluid filled to aid in cooling by increasing heat absorption capability. If they can keep the fluid in them they can last a long time. If they get hot and the fluid leaks out they will eventually fail.

 

[BodunkPHilroe1]

Re: ignition coils are they either good or bad or can it be weak

Can they overheat and malfunction? I am having an issue with my boat running strong for an hour or so and then won't restart. Can the coil cause that?

 

[BodunkPHilroe1]

Re: ignition coils are they either good or bad or can it be weak

I have not on the water at that time. Given it ran fine the next day I assumed it was not the coil.

What is the correct way to test the coil with an OHM meter?

 

[JustJason]

Re: ignition coils are they either good or bad or can it be weak

Start your own thread Bodunk

 

[nailem]

Re: ignition coils are they either good or bad or can it be weak

full tune up last year. new plugs, wires, cap, rotor, oil change, checked in tank fuel filter and filter on carb was cleaned. new water separator. new water pump impeller, out drive gear lube, bellows (all 3), lower shift cable, gimbal bearing. belts on motor. the only other thing i need to do is a carb rebuild although i think i will wait for my short Erie PA season to be over first.

any other suggestions would be appreciated.

i can look it up but what should the ohms be on the coil?

 

[nailem]

Re: ignition coils are they either good or bad or can it be weak

bump