Suzuki DF150 spark plug lifespan / change interval ?

[jack daniels marine]

This motor is a 2014 model with 190 hours on it. I have not inspected the plugs. How long can they be used before performance deteriorates?
The Suzuki owners manual only specifies " inspect every 12 months or 100 hours". There is no change interval mentioned.
The boat just seems a bit sluggish this season, It's probably the family putting on weight, however I don't mind spending a few $ on 4 spark plugs if it will help.

Are iridium spark plugs better? The "standard" plug in the DF150 is a V-power platinum BKR6E, according to the owners manual.
I do quite a lot of running at just 2000 rpm.

 

[99yam40]

I would stick to the plugs recommended

 

[ondarvr]

As long as the plugs are firing they offer little in the way of performance, gapped correctly they will be fine, so check that.

 

[jack daniels marine]

I have no experience with plugs in outboards, however plugs in similar standard car engines usually have a change interval of 40,000 miles at least.
That is 1600hrs in my car and after this time the gap is still usually within spec.
Are outboards harder on plugs than a car engine?

 

[ondarvr]

Outboards run at higher RPMs, so per hour they fire more often, but the plugs don't tend to wear out that fast. Decades ago in old 2 strokes with dirty oils and leaded fuel the plugs became fouled far more often, this mindset of frequent plug changes lingers and the first thing people do is change the plugs, it rarely helps, but may give you an indication of how the motors running from their condition, plus they're cheap and easy to change. Expensive plugs with exotic metals aren't "better", but they tend to last longer, so if you plan on long change intervals they work well, if you're going to change plugs every year it won't make a difference.

 

[jack daniels marine]

I doubt the spark plugs are affecting the performance then, with only 190 hrs on the motor.
Old fuel in the tank from last season may be reducing performance.

 

[99yam40]

higher the RPM the compression may change some and I have seen plugs not spark properly under compression.

does not hurt to try new ones

 

[Bayou Dave]

For what it's worth, my 2002 Suzuki DF140 manual says to inspect the plugs every 100 hours or 12 months and to change them every 200 hours or 12 months.