Spark Plug Change Frequency

B

Blue Cruiser

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Joined
Sep 16, 2006
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23441
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We have twin 5.0 liter 260 HP fuel injected Volvo Penta inboard/outboard engines in our cruiser. How often do you change spark plugs? How often do you add fuel injector cleaner? Do you have a preferred brand of fuel injector cleaner? The price on fuel injector cleaner seems to vary greatly 44-K (Napa store) being the highest at about $21.00 a bottle. This week both lower units were removed, serviced and re-installed. I then changed oil and oil filters on both engines and the fuel water separator on the starboard engine and added inexpensive fuel injector cleaner. The starboard fuel water separator had sediment which was visible when dumped in a whit plastic bucket. After about twenty minutes the starboard engine ran better, but would only wind up to about 4300 rpm at full throttle. I added fuel stabilizer to each tank and filled with gas. I then ran the boat for another twenty minutes and winterized. What should I plan on in the spring? Add more fuel injector cleaner and run or change spark plugs first. The existing plugs have 300 hours on them and are three years old. The port engine ran fine without adding fuel injector cleaner. Both engines have been run for 785 hours in fresh water.
 
Out of all that, yes, change your plugs every 3 years. Not for service life, but so they don't rust in place. Change the fuel filters each spring and more often if you see more crap in them next spring. Add no injector cleaner. Do add Stabil in the fall. Change your oil and filter each fall prior to lay-up. Follow the Volvo specs for your outboard service intervals.
 
Change spark plugs every spring. Fogging the engine when winterizing does nothing good for the plugs.
 
Not sure the year of your motor, had a 2004 8.1 crusader motor, 2008 changed the plugs, the ones I pulled out were as good as the new ones I put in. 150 + hours at that point. With that said, they had platinum , plugs that are rated for 100k in cars. Fuel injector cleaner, never on any boat or car. Oil changes, at the minimum once a year. Fuel filters, every few years, you may need it sooner depending on the quality of the fuel you get and how long it sits in your tank.
If you have an older boat, that went through the transition of ethanol, well then that is a game changer of all I stated.
 
quote:
Originally posted by Padraig

Change spark plugs every spring. Fogging the engine when winterizing does nothing good for the plugs.

Click to expand...


Fogging oil has nothing in it that doesn't burn off in 30 seconds after the next start. That being said, changing the plugs won't hurt anything either.

Fuel injector cleaner and other snake oils are not needed. That's my opinion and I'm stickin to it. To properly clean injectors requires special tools. Spend your money first on new fuel filters.
 
You've gotten good advice here. Most marine spark plugs never get enough usage to wear out. Changing them every year or two is just cheap insurance that a plug doesn't rust in place or rust out on you. There was a problem with some spark plugs blowing apart from rust-out. I think they were the Champion brand, but I'm not sure. A search on the forum should bring up some threads on plugs. I also don't recommend injector cleaners. They're rarely necessary simply because marine engines operate at close to maximum RPM, cleaning the injectors through the additives in the fuel. Fuel stabilizer is necessary because of the ethanol in our gas. Is you start to see grit in one of the fuel filters, you may have to have that fuel supply tank cleaned. Other than that, follow the manual for your engine and you'll be fine. Hy
 
Your maintenance schedule should reflect where and how you boat. Mfg recommendations are just that, GENERAL recomendations.

I run in saltwater with an average water temp of 60*. I change oil/filters 4-5 times a year and I use auto plugs. I average 250 hrs a year so I change everything an average of 50 hrs.

This schedule keeps me up close and personal with my engine and boat. Tuna trips take anywhere from 110 to 170 miles and up to 50 miles off shore. Things tend to break or go wrong under the worst conditions. I try to reduce those possibilities.
 
I change plugs at the end of the summer season, around 75 hours. Boat is trailered to Florida for the winter for another 75 or so hours so that means another plug change. Cheap insurance to avoid trouble. I use anti seize on the plugs so they come out easy. When I bought the boat it took me a week to get the plugs out. Used a lot of penetrating oil to loosen them. Not going through that again. Thought sure I would break one.
 
Volvo has a recommended maintenance schedule. Your choice is to follow what the engine manufacturer recommends or try to guess which stranger on the Internet knows better than the manufacturer.

Me, I follow the manufacturer's recommendations.
 
quote:
Originally posted by rawidman

Volvo has a recommended maintenance schedule. Your choice is to follow what the engine manufacturer recommends or try to guess which stranger on the Internet knows better than the manufacturer.

Me, I follow the manufacturer's recommendations.

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No disrespect, but maintenance schedules by all manufactures are way off the wall on what you need to do. Of course, throwing away money for needless maintenance is fine in my book if that makes you sleep better.
 
The BG 44k is excellent stuff It wont hurt a thing. I don't know how much fuel your boat holds but if you add the 44k make sure you have enough of it for the amount of fuel in your tanks. The 44k I NOT the cheap stuff from Advance or Walmart it is really good for the fuel systems. It is the best stuff out there to use .....that is if you don't have them professionally cleaned with a system . The throttle bodies and IAC motors should be cleaned while your at it .
 
1. Has ANYONE ever worn out a set of plugs on an injected engine?

2. Has ANYONE experienced plugged injectors from "bad gas" on a boat that was used regularly?

3. Reread waltery's post. His advice is appropriate for 99% of boaters.
 
Curious, are those who say their plugs last 3 or4 years and 150 hrs. Were the plus checked regularly during the 3 (or more) year interval?

Supposedly we have experienced boaters here. Spark plugs can tell you a lot about your engine. If your engine is running perfect, you're lucky. If it's running rich or worse, lean, and the plugs aren't checked and they foul out on you in the middle of your trip...or they burn up the engine from being over lean. Both of these problems are potentially life threatening that could have been remedied.

Of course, some may say they are checked by the dealer or mechanic...just ask barre river

http://www.boatered.com/forum/topic.asp?TOPIC_ID=163437
 
My engines use Iridium plugs that do last quite a long time, but I agree 100% with Charlie that the only way to know the condition of the plugs and gap is to pull them and look . I probably replace them about every 3 yrs even though they look good just as preventative maintenance, but I try to get them out once a year to see what they want to tell me about combustion conditions. And I clean them up a bit, check or re-gap and reinstall with a slight bit of never-seize on the thread and dielectric grease on the upper exterior of the plug and inside of the boot.
It's hard enough getting anywhere near those plugs and getting the boots to release (they would never come off without straight boot pliers since I can only barely touch them with 1 or 2 fingertips).
If I put that off for "undetermined time" and waited until I thought a plug was bad, it would be nigh onto impossible get them out even without problems from SW corrosion (ever had a RW pump leak and spray water?) or concern for neglected plugs running lean and breaking off ,etc. .

And FWIW- Like Charlie, I also change oil and filter approx. every 50 hours just as Crusader specs for these higher revving Vortec engines like most gas-inboard engines of the past 10-12 yrs or so. The oil on top may look great on the dipstick with engine off , but it still looks black at 50 hrs when pumped out . And to my mind that black is contaminants the engine would do best without for best life and performance. Probably serious overkill at 50 hrs unless running often at very high cruise RPM (I don't), but on boat engines particularly it seems wise to stay pretty close to the mfgrs' preventative-maint. specs. .

Do you remember to check pencil anodes every 30 days and replace if ~50% visibly missing since the rest is very porous? A couple friends had to replace $$$ heat exchangers or coolers this year and flush the SW out of the engines or oil since they habitually only replaced the $4? missing pencil anode insert once a year.
 
No, I do not pull the plugs and inspect, as I do not pull the plugs in my cars either. And the cars get far greater hours of out of the plugs than my boat. Yes, my engine is running perfectly. No I'm not lucky, I'm just prudent in keeping up with maintenance and know what to look for from the standpoint of fuel burn, odors, and sounds. If my engine wasn't running perfectly, I would be foolish to ignore the symptoms. I might pull a plug or two then to inspect them. With today's engines, oils, and plugs, the days of yearly tune-ups are over. I only change them based on my maintenance schedule.

The situation Barrenriver had has nothing to do with pulling plugs and inspecting them. He bought a boat at auction and inherited the problems of the boat. How would pulling plugs aid in diagnosing electronic throttle problems?
 
Every spring after starting and running on the hose. I still believe that fogging the engine does not do the plugs any good. If I am wrong.....the new plugs will not break me and I get a chance to inspect the old ones
 
There is a hell of a lot of expence incurred by boaters fixing items that are not broken.
 
Stephen, You've been here from the beginning. Surely you don't equate a daily driven auto to a boat that at most is run once or twice a week for part of the year and sits for month on end.

An engine running lean will seem to run normal as it melts your pistons or exhaust valves and plugs.

You do maintenance and check plugs and that's my point. You're gonna catch them potential problems only if you're down there fiddling around the engines(s).

I mentioned BarrenRiver only because he asked, as well as others, if the drives were checked. In fact he asked again and again and was assured they were checked. What I'm getting at is DO NOT TRUST the guy doing the work or more importantly, the guy overseeing the work. He DIDN'T do the work, he just assigned it so he's just saying what was supposed to be done...and he probably has gotten away with it for years.

I'm just saying...
 
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