How often should ignition coils be changed?

[iamsaws]

Hi,
I have a 1997 40 HP mercury. It was bought new by my grandfather. Still runs good. Im just curious to how often the ignition coils should be changed and is it worth it to just go ahead and buy four new ones (4 CYL) and do preventive maintenance. I am also hoping this will minutely help with gas consumption.

thanks!

 

[444]

Nope. Waste of money, if they're working fine, leave em.

 

[gm280]

You change them when they stop working and not a minute before...

 

[iamsaws]

Ok!

Thanks! And that goes for all the ignition components?

 

[scrapper042000]

very rare issue on that one ,no worries ,if anything the switch box can cause a miss on one cylinder or a no spark condition ,if that is the 4 cylinder version I am thinking of ,good classic copy and block from the merc 50 hp dependable motor ...if you have the other version ,I think your only concern is time for a new water pump impeller ....for a piece of mind ,merc impellers are small in design and not long lasting compared to other brands ..and check your lower unit oil before operating

 

[hotrod53]

I have 3 of 4 original coils on my 1977 Merc 500. Leave them alone and run it. Leave a plug wite off and watch one melt down.... And I can prove it, lol.

 

[iamsaws]

thanks again. What would be best practice maintenance? Everything seems to be running fine. Is there something I should do to ensure that? I only run non ethanol gas. Change the spark plugs each season etc. My ultimate goal as everyones is when I go to start it, it starts. thanks!

 

[Chinewalker]

New water pump every 2-3 seasons. Check all hoses for deterioration. Drain and refill lower unit oil at end of every season. Check propshaft for fishing line.