Changing spark plugs

[Bad Habit]

How often should plugs be changed? Boat is used mainly for fishing so it’s at trolling speed 90% if the time. It’s a 1987 350 Chevy mercruiser with a little over 5000 hours. It still runs fine but the plugs have not been touched in a few years. Is it a “ if it ain’t broke don’t fix it” thing?

[High Bidder]

I was wondering the same thing. Your plugs are relatively easy to change but I have a 302 Ford engine. I have to remove the exhaust manifolds to change plugs so I have not been enclined to change them often. Also plug wires are not available for Ford engines so I am hesitant to pull the wires and risk breaking one. I haven't changed the plugs for the last 5 years when I installed new manifolds but I only use my boat for about 200 hrs each year.

[tuffishooker]

Take a-plug out and look at it #1 The spark plug wires do not last forever either ! Two opposing views #1 If it ain't broke don't fix it ! #2 Follow a regular service plan ! No easy answer but every mechanical issue I have had has been lack of regular service on my part ! Remember that FRAM commercial " Pay me now , or pay me later but later is always more !" Thanks for asking this is a great site !

[Sk8man]

High Bidder - Not sure what plugs were used the last time installed but usually the Platinums are installed when new and they are intended to last for 100,000 miles on cars with that engine. If subsequent plugs were those I should think you should be good with only that much use despite the use being different than on a car. Those plugs are very fragile and often break during removal and a special tool  may be required to get out the plug if that happens.

[tuffishooker]

Plugs MAY be easier to remove if the block is hot/warm ! Put on Anti-Seize lubricant [ Permatex] on the plugs when re-instating ! Again if you are going to change the plugs change the wires and you are done !

[Iceman]

7 hours ago, tuffishooker said:

Take a-plug out and look at it #1 The spark plug wires do not last forever either ! Two opposing views #1 If it ain't broke don't fix it ! #2 Follow a regular service plan ! No easy answer but every mechanical issue I have had has been lack of regular service on my part ! Remember that FRAM commercial " Pay me now , or pay me later but later is always more !" Thanks for asking this is a great site !

Tuff;

 

Love your honesty about owning the mechanical issues, as I feel the same way.

 

John

Edited September 27, 2020 by Iceman