Motor issue

[the butcher]

How often do folks here change spark plugs? What are the most common issues related to spark plugs that haven't been changed out in time? Anyone have motor issues such as loss of power amd vibrations when trying to get up on plane? This is what I am experiencing and wondering if it could be spark plug related. 200 hrs on my 4 year old 4 stroke 115 with original plugs. Of course it could be a host of other causes like bad injector or coils etc but wondering if my symptoms are low or highly attributable to leaving the plugs in for the 4 years and 200 hrs without changing them out... have ordered new plugs and will swap out hut just curious if others have had same symptoms and it fixed it with new plugs.it

 

[ryanb]

I'd say that it would be unlikely to be spark plugs. Fuel issues would be my guess. Change all your filters if they are due, check for blockages, injector cleaner, maybe some seafoam as well for good measure. Make sure there's no water in the fuel. Is your gas fresh?

 

[Old Fisher]

Your symptoms could be fuel or ignition related. Changing spark plugs is always a good idea when experiencing ignition problems and yours are due. Also look at the plug boots at the same time. Ryanb is correct about fuel filters, etc. Do the easy and obvious stuff first. It’s just good maintenance and it will eliminate some of the possible causes of your issue. Then test and let us know.

 

[RogersonCrusoe]

In my experience changing/inspecting the sparkplugs are the result of other things going wrong. Too much fuel, water/corrosion issues, coils etc... Never had a problem with just the sparkplug.

Edit, if you suspect a sparkplug issue, check it for spark by grounding it against the motor and turning it over (use insulated pliers and/or hold the rubber boot. If it sparks consistently, then you're good

 

[scott craven]

First thing I would do is run 1/2 can of seafoam in a 5 gallon tank of fresh fuel through the motor.
Good possibility it will fix it.

 

[zurk]

i change my plugs annually with the annual service. i'm too lazy to inspect them and too paranoid to keep old ones in. plus they are cheap as all hell and an extra twenty bux is not going to harm anything.

 

[Aces]

200 hours isnt much I change mine every 350

 

[sly_karma]

While it's good to change maintenance items like plugs and fuel filters anyway, blindly throwing new parts at an engine problem is an expensive substitute for actually diagnosing the problem. If you haven't already done so, get the factory service manual for your model, and a cable and diagnostic software. Those are valuable tools and you may well be able to figure it out. Beyond that there are dedicated online user groups that provide useful help ( vs generic groups like social media or THT).

 

[sasqman]

i change my plugs annually with the annual service. i'm too lazy to inspect them and too paranoid to keep old ones in. plus they are cheap as all hell and an extra twenty bux is not going to harm anything.

Same same. Plugs and fuel filters every year. Easy things to eliminate.

 

[gone fishin]

did I miss it, but what kind of motor are you running?

 

[Corey_lax]

200 hours isnt much I change mine every 350

350 is good but I’d imagine the break in period would be harder on the plugs compared to once your fully broken in.

I’d put my money on fuel filters but I’d still change the plugs to get a fresh start on the maintenance schedule at 200 hours

 

[Aces]

350 is good but I’d imagine the break in period would be harder on the plugs compared to once your fully broken in.

I’d put my money on fuel filters but I’d still change the plugs to get a fresh start on the maintenance schedule at 200 hours

agree about the filters

 

[Brando]

Not uncommon for the porcelain to crack on a plug and arc out or a wire/coil to to crack and do the same. Usually shows itself a under load.

 

[ship happens]

115 4 stroke what exactly ? Big difference there

If it's merc then the plugs fail. Seen it several times in my career only on the merc four strokes. Seen total misfires repeatedly due to plugs not functioning. The coil pack CDI coils also fail once and a while.

 

[Fixit]

if your using platinum plugs you could likely leave the plugs in til the engine died, if they're standard plugs I would inspect them every 100 hours while changing the oil to know how they're doing. would likely last 3 seasons without troubles
I ran my truck for 200,000kms on the original platinum plugs before I noticed a rough idle

 

[jim morrow]

Old plugs have a bigger gap, so starting is harder. 200 hours is old. If it was an I/O and could not get up to plane, then distributor prolly worn out...

 

[gunnerlove]

Pulling them to inspect costs $zero.
Finding a cracked electrode is causing a miss before throwing real money at it.... priceless.

 

[Foxsea]

I hope you have it figured by now. We had a Yammy F115 since 2006 and changed the plugs once in over 1200 hours. Not cause we had to, either.

Fuel issues are much more common. Water in fuel is a common issue. Filters are a for-sure change. Could go as far as injectors but that's an easy change-out, too.