Changing spark plugs

[REELMAN]

how often do you all change your spark plugs in your motors?

[walleyewacker]

Reelman,

I'll be interested to hear the replies. I had my old boat
winterized by the dealer for the 3 years I owned it and they
never did change the plugs. On the invoice it said they checked
them,ok. And I never had a problem fowling them. And who knows
how many years before I got it that they had been replaced!?

[FlyBoy]

I change mine every spring (after storage).

I've never had a plug problem, but who knows if I would have if I didn't change them?

Its just part of the spring ritual I guess.

-John

[fishhunter]

If the plugs are cheap or if I fogged the motor I would change them after running the fogging oil out. On my Opti I had 200 hours on it and never did change the plugs.

[Hangman]

My Opti always blew the powerhead before the plugs needed changing. Good thing cause the 2 on the bottom are a bear to change.

[MarkG]

I am not one to wait until the plugs deteriorate to where they are giving me problems, I prefer that the motor is always running at optimum. So I change mine every spring, after I have burned out the fogging oil.Plug performance deteriorates so gradually, hard to even notice mostly until a new set goes in. If you troll a lot,especially with a 2 stroke they should be changed out more often for optimum performance. A 4 stroke that is only being used for cruising, or a lot of WOT,and very little idling, can probably get a lot more time between plug changes,maybe even several seasons.

[eyeman_1]

I most likely don't need to but I change mine every spring after running out the fogging oil and the old gas in the boat. I don't see a big issue with fouling but I error on the cautious side. I spend a good deal of time fishing big water and don't want any issues with my motor. I also keep a spare set of plugs for the main and kicker motor on board just in case. Why not?

[moldmakerIL]

Going on the 8th season for the plugs in the 175EFI.
Change them every other season in the 9.9four.
Maybe time for a change eh?

[Bradnd]

On my 4-stroke kicker, I put in new plugs each Spring. Will pull them out once during the summer for cleaning. I put alot of hours on the kicker compared to the big motor. I also pull the plugs on the big motor & clean up each Spring. Used to change them every couple years. That may change now, since I have upgraded to a hpdi.

It all depends on how the motors are run, alot of idling, trolling, & etc and how many hours are put on them. Plugs are cheap insurance for keeping your engines running at peak performance.

Take care,

Brad

[Nordicron1]

I use to change out in spring but now the last 2 years I have just been taking them out and scrubing them off with a little seafoam and they look as good as new. Only takes about 1min to clean each plug. Can do this as often as you want to always keep them going strong.

[THILL]

I do the same(clean them up and put em back in)on my OPTI and the look good as new. Soon as I see some wear on the electrode I'll change em.

[Eighties Pike]

Be carefull guys when changing plugs not to strip your thread
reinstalling the plug. I did this on a 40 4-stroke merc last fall. They had to take the head off to fix it right and it cost big $$.
It can happen to anyone I'm sure. I learned my lesson the hard way.
Just be carefull.

[REW]

Note on changing plugs.
Yes, it is fairly easy to strip the threads on an aluminum block.
This is why, I ALWAYS put anti-seize compound on every spark plug when I put it back in the block.
Then, when you go to change it a day, year, or 10 years later, the plugs will come out, without taking the threads with it.

--
With respect to changing plugs -
I also used to change the plugs every year.
However, I am currently going on the 4th year with no plug changes.
The engine runs, starts and idles fine, with no change in gas mileage. When I pull the plugs they look fine, so I simply reinstall them.

I do run synthetic oil, which helps to preclude plug fouling. I suspect that that probably does help the plug situation.
Bottom line - if you want to change the plugs, go ahead. However, if you compared this to changing plugs on your car - and lets say that an average fisherpersons motor runs for 75 hours a year - which might be typical or not -- how does that compare to your car.
Lets say that you run your car for a few years, and lets say that you run your car with an average speed of 40 mph. idle, midrange, start stop long trips - Lets also say that you do the average of 15,000 miles per year. This means that you will have about 375 hours per year on your car engine. Now, lets say that you go to an old time plug change of once every 30,000 miles. This would equal changing the plugs every two years at 15,000 miles per year.
This further means that you will be putting 750 hours on your engine in that time.

So, does it make a lot of sense to change outboard spark plugs at 75 hours, when you typically run a very conservative 750 hours on your automobile spark plugs??

I suppose if you have a poorly set up engine, if you do a lot of very low speed running, if you tend to foul out - due to oil fouling, cold running and or incorrect carb setting.

But, if non of the above were true - and probably more representative of todays four stroke engines - the typical outboard should go at least 10 years before a plug change is required.

Take care
REW