Spark Plug recommendations...

[Touch of Madness]

I have a MY 2000 Larson Cabrio 290 with twin 5.0Gi PEFS Volvo Penta engines with duo-props. (serial #s: 4012013531 and 4012013532) Ever since the end of last season, I've lost 800 rpm off WOT on both engines. My fuel consumption has also increased from 17gph (at cruise) to almost 25gph and I don't have as much power getting on plane. I pulled the plugs from both engines and they were all wet. I suspect the non-Volvo plugs the marina said were comparable run too cold for my engines - unfortunately, I don't have the models #s of the plugs but they are Champians. Can someone recommend a good plug for these engines other than the standard recommendation from Volvo (can't always find them) that's good for cruising and some trolling? I'd like a plug that runs hotter (better performance and fuel consumption) even if I have to replace them every season or two. I put just over 100 hours on each engine per year.

 

[Bondo]

Re: Spark Plug recommendations...

AC, MR43T is the plugs you need,.......

If your motor is running Rich,...... That's a Carb Issue....

Hotter Plugs won't Fix a Carb Problem........

 

[Touch of Madness]

Re: Spark Plug recommendations...

If you don't know that these engines are Electronic Fuel Injected, is the recommendation still good?

 

[Bondo]

Re: Spark Plug recommendations...

Ayuh,.....

Regardless of it's Induction System it takes the AC MR43T plugs.......

If it's EFI,..... It's Still Too Rich......
But,... I'm not the 1 who's going to tell you How the Lean it Down.........

Just because I don't know How to Fix it,..... Doesn't change the Prognosis.........

 

[Touch of Madness]

Re: Spark Plug recommendations...

If too rich = carb/EFI issue, implying all plugs burn fuel equally, then why the MR43T recommendation?

Not trying to be ungrateful, just trying to insure that I get advice from someone who understands that a running rich problem caused from running a cold plug can be fixed by running a hotter plug.

 

[bruceb58]

Re: Spark Plug recommendations...

It may actually be the AC mr43lts on your engine. The Vortec heads need the longer plugs. If you look on your engine, there should be a decal that tells you what the number is.

Bondo gets no love!

 

[Bondo]

Re: Spark Plug recommendations...

Good Catch Bruce,..... I didn't notice the Year.....

ToM will have to make Sure his motor In Fact does have the Vortec Heads......

ToM,... Does your Intake Manifold have 8 bolts(4 on each side) holding it to the motor,......
Or are there 12 bolts(6 on each side),..??...

IF it's the Vortec motor(8 bolts),..... Then you'll need the Longer AC, MR43TLS plugs......

Other than That,........
The Fuel to Air ratio is controled by the Induction System, Carb, EFI, Whatever,.....
NOT by the Heat Range of the Sparkplugs..........

Increasing the Heat Range of the Sparkplugs is a Band-aid, that Doesn't Fix the Issue,....
It just Masks it,+ Co$t$ you Wa$ted Fuel.........

 

[newport dave]

Re: Spark Plug recommendations...

Are you sure it's not just a dirty bottom? (the boat I mean).

Dave

 

[Reel Poor]

Re: Spark Plug recommendations...

In 1999 and 2000 volvo had problems with those engines and said to only use the Champion RS12YC spark plugs ONLY. Failure to do so will cause engine failure. This type of failure is not covered under you Volvo Penta warranty. I read the service bullitin some where but cant remember where. I'll try to find it.

I tried to run the AC replacement plugs in my personal owned 2000 5.0 Gi (I hate Champion plugs) and they definitely effected performance. Went back to the Champions and problem solved.

 

[180shabah]

Re: Spark Plug recommendations...

http://www.sparkplugs.com/

Bondo, what happened to the "mugshot"?

 

[Bondo]

Re: Spark Plug recommendations...

Bondo, what happened to the "mugshot"?

The Joke with Haut had ran it's course,+ the Ugly guy who was following Me around was causing abit of a Problem.......
Down in the Boating forum, there's a Stolen Boat thread that really took the cake,.....
And,....
About the same time Xtraham had just changed to a New avatar,.....Due to te fact that I've Loved this avatar ever since I saw it on Xtraham's posts,... I asked Tom if he was Done with it,+ could I use it......
God Bless Him,... Tom agreed,+ sent it to me,.....
Being the Motorhead that I am,..... I'll be wearing it Proudly..........

In 1999 and 2000 volvo had problems with those engines and said to only use the Champion RS12YC spark plugs ONLY. Failure to do so will cause engine failure.

I'd like to hear More about this,........
It just Doesn't Add Up to Me.....................

 

[Reel Poor]

Re: Spark Plug recommendations...

In 1999 and 2000 volvo had problems with those engines and said to only use the Champion RS12YC spark plugs ONLY. Failure to do so will cause engine failure.

I'd like to hear More about this,........
It just Doesn't Add Up to Me.....................

I haven't had much time to try to find it yet. I did do some looking but was unsuccessful. I can post a pic of the sticker the was Volvo Penta installed on the origional engines I pulled out of my boat. Would you like to see that?

Maybe when Don gets back he may know more.

 

[Don S]

Re: Spark Plug recommendations...

Here is that Service Bulletin.

 

[Bondo]

Re: Spark Plug recommendations...

Is there a cross to AC,...??....

 

[Tail_Gunner]

Re: Spark Plug recommendations...

None here: http://198.208.187.182/internet/VehicleCrossReference.jsp?autosel=A&part=+RS12Y

 

[Gary H NC]

Re: Spark Plug recommendations...

Not to hijack but i asked for ac MR43T plugs at Napa and they said the new # was AC 10,, Does that make sense or did i get the wrong plugs?

 

[Reel Poor]

Re: Spark Plug recommendations...

Ya know guys this is the reason we have to go by the manufacturers guidlines. Sometime there are factors that we don't know about and cannot get information on about the reasons behind the designers choich to use a specific part. In this particular instance Volve has obviously done something to the engine to change the combustion chamber activity and the AC plugs could not handle the change. Volvo Penta went to the drawing board and figured out the problem and came to the conclusion that a Champion plug would do the job. Sometimes it's not a smart move to change out a factory part (name brand that we may not like) for a different name brand part that we "think" may be superior. I also feel these type problems are more prevelent in todays computer controlled engines and will get worse in the future. Sooooo......If you stick to the manufacturers application chart/guide you shouldn't run up against this type of self inflicted problems.

As for the bulletin DonS posted there is more info out there somewhere that goes into a more detailed description about the problems that were occuring with the engines. It's been probably five or six years ago that I came across this stuff. For the life of me I can't remember where it was. Believe me if I could find it I would post it.

 

[Don S]

Re: Spark Plug recommendations...

I agree 100% with what RP says.
Volvo also doesn't tell it's dealers or techs the WHY on anything. All they do is say "DO THIS" or DO NOT Do This"
While it would be nice to know what is going on in the corporate offices, trust me, we will never be invited.
There are people here that like to speculate, but in reality, they are only guessing.
Like RP says, use what is recommended. If you don't then deal with the consequneces. Rather it's spark plugs, Oil, oil filters, fuel filters, or electrical parts. Just because something LOOKS the same as a cheep imitation part doesn't make it work like the real thing.

And BOATS are not the same as CARS..... Deal with it.

 

[Touch of Madness]

Re: Spark Plug recommendations...

Everyone, THANKS FOR THE ADVICE!! We DIY'ers don't get bulletins. Don, any idea as to what gets damaged and symtoms of that damage? I'm wondering if my lack of power and excessive fuel consumption is an indication of such damage?

 

[bjcsc]

Re: Spark Plug recommendations...

Your lack of power and excessive fuel consumption is related to your plugs being wet as you said in your initial post. I don't know if you meant wet with water or wet with fuel. I would assume wet with fuel is what you meant, and your combustion ratio is way out of whack. Sounds to me like your system is dumping fuel and you need to figure out why. Keep in mind that if your plugs are getting that wet with fuel you're probably washing down the cylinder walls a bit, too. Is your oil diluted with fuel?

BTW, that's the same plug I use (RS12YC)...