4 Stroke spark plugs

Bigfoot

Well-Known Member
Joined
Jun 15, 2009
Messages
113
Reaction score
1
Points
0
Location
Alpharetta, Ga.
Why are the 4 Strokes using up spark plugs at such a fast pace? How many hours are you getting from a set? Anything to make em last?
 

Pez Vela

Well-Known Member
Joined
May 7, 2008
Messages
218
Reaction score
1
Points
18
Location
San Diego
These were replaced after 700 hours. Something's wrong with your motor.
 

Attachments

  • IMG_0848.jpg
    IMG_0848.jpg
    150.6 KB · Views: 3,888

Doc Stressor

Well-Known Member
Joined
Nov 13, 2009
Messages
1,186
Reaction score
295
Points
83
Location
Homosassa, FL
Model
Seafarer
Yep. I pulled mine after 400 hr and they were fine. Didn't even need to be re-gapped.

Have you been burning stale fuel or doing a lot of trolling?
 

Bigfoot

Well-Known Member
Joined
Jun 15, 2009
Messages
113
Reaction score
1
Points
0
Location
Alpharetta, Ga.
Doc Stressor said:
Yep. I pulled mine after 400 hr and they were fine. Didn't even need to be re-gapped.

Have you been burning stale fuel or doing a lot of trolling?


slow trolling yes...
 

Doc Stressor

Well-Known Member
Joined
Nov 13, 2009
Messages
1,186
Reaction score
295
Points
83
Location
Homosassa, FL
Model
Seafarer
There you go. Slow trolling will do it. 50-100 hr is all you can expect.

Generally the plugs are OK, just fouled. You can clean them with a soft wire brush most of the time. Be careful not to damage the electrodes. Re-gap if necessary and put them back in.

If you run RingFree and keep the fuel fresh they will last longer.
 

Bigfoot

Well-Known Member
Joined
Jun 15, 2009
Messages
113
Reaction score
1
Points
0
Location
Alpharetta, Ga.
Doc Stressor said:
There you go. Slow trolling will do it. 50-100 hr is all you can expect.

Generally the plugs are OK, just fouled. You can clean them with a soft wire brush most of the time. Be careful not to damage the electrodes. Re-gap if necessary and put them back in.

If you run RingFree and keep the fuel fresh they will last longer.


from long slow rides out of the river to pulling plugs around Lanier, suppose the low speed hours added up. sure didn't like my awesome running 4 banger spittin and well you know...

she was due for service anyway,. he'll get that to..he actually said the 4 bangers like em faster than the 2's In saying that, I had a 70 rude with 8 seasons of zero service....was an old motor on an old pontoon with no trailer...figured I'd repower when she died, problem was she never missed a beat...sold the whole rig after 8 years for 2500 and paid 3000 for her...$62.50 a year and I bet at least 1000hours +
 

richie rich

Well-Known Member
Joined
May 20, 2009
Messages
1,183
Reaction score
1
Points
0
Location
south windsor, CT
Doc Stressor said:
There you go. Slow trolling will do it. 50-100 hr is all you can expect.

Generally the plugs are OK, just fouled. You can clean them with a soft wire brush most of the time. Be careful not to damage the electrodes. Re-gap if necessary and put them back in.

If you run RingFree and keep the fuel fresh they will last longer.


other than maybe getting a little fouled from a rich mix, what would happen to the plug from slow trolling?
 

seasick

Well-Known Member
Joined
Aug 19, 2008
Messages
9,531
Reaction score
1,420
Points
113
Location
NYC
Personally, I don't like using a wire brush. If a small piece of bristle breaks off and ends up on the plug, it can drop into the cylinder and do damage to the cylinder. Plugs are relatively cheap compared to a rebuild:)
If your usage is usually limited to trolling, you might be able to go for a hotter plug. A good marine shop should be able to advise. Some of the spark plug manufactures may aslo offer information on different temperature rangs plugs. Of curse a hotter plug will burn up fasetr if run at high speed or. load
The first question that you answer is what condition your bad plugs are in. If they are just fouled, a hotter plug can help but if the electrodes are eroded or otherwise damaged, you have a different issue that needs to be addressed. I would also consider what additives if any you are adding to your fuel. Some may be a good thing but more is usually not necessarily better.
 

L.R.

Well-Known Member
Joined
Dec 4, 2013
Messages
80
Reaction score
1
Points
0
I agree you have something going on.I've run an 2005 225 Optimax since new...950 hrs.. I will Troll for 5-6 hrs...Plugs looked great after 300 hrs.! And thats a DFI 2-stroke..Now that being said...I will run Her for 15-20 mins. at 5K rpms.comin' back.I would think 4-stroke Plugs would last at least as long.Now that I have a F-225 Yamaha.We will see.
 

Fishtales

Well-Known Member
Joined
Jan 31, 2005
Messages
8,033
Reaction score
1,286
Points
113
? part of the yearly maint cycle to ensure a trouble free season.
 

georgemjr

Well-Known Member
Joined
Jan 2, 2009
Messages
442
Reaction score
38
Points
28
Location
Bay Shore, Long Island NY
I change mine every spring, after I have used the boat for a few hours (I like to start it up on the old plugs while I burn off the fogging fluid). I never thought of trying to get more time out of them, about 100 hours/season (although you all have me thinking now). I have heard that you should run those motors at top RPMS for a minute each full hour of use. I do not necessarily do that (I just hate "beating" on the boat), but I do open it up from time to time to clear it out. I have heard this recommendation from various sources.
 

Bigfoot

Well-Known Member
Joined
Jun 15, 2009
Messages
113
Reaction score
1
Points
0
Location
Alpharetta, Ga.
All I can say is running non-ethanol fuel and she was "cutting out", changed the plugs and like new again...

happens to my 4 stroker jet ski and my buddies...maybe the fuel on Lanier...