Merc 3.0 Issue

[joey76]

Good Day All,

Hope someone can help...

My boat is an 03 Bayliner 185BR with a merc 3.0. Very low hours, ran perfect last summer. Then last fall I changed the plugs, gear lube, oil, drained the block and exhaust manifold, fogged it, put stabil in a full tank and stored it for the winter.

I took it out for the first time this season and upon wot a clicking noise was heard coming from the motor. It sounded like raw spark on metal..I shut her down and checked in and around and found nothing out of place. Fired it back up and attempted wot again...Same thing happened after about 60 seconds or so only now I noticed I was also losing power...Brought it down to idle, clicking stops and power is back...Tryed it again and the same thing happens. Temp was normal as well as the oil pressure. What am I missing?

Help Please

Thanks,
Joe

 

[Bifflefan]

Re: Merc 3.0 Issue

What about the cap rotor and wires???
if it has multi coils then could be one arcing to ground.
Try running it in the dark and see if there is anything odd.
Just my thoughts...

 

[bomar76]

Re: Merc 3.0 Issue

if it has multi coils then could be one arcing to ground.

What 3.0 liter Mercruiser ever produced had more than one coil?????????????

 

[joey76]

Re: Merc 3.0 Issue

Coil and wires are in great shape. I just pulled the plugs and #1 looks pretty bad. I cant decide if it would fall under detnation or not..The Ground Electrode looks like it became way too hot and is melted a bit..I think? Some of the Center Electrode looks to shaven down a bit as well.

 

[fat fanny]

Re: Merc 3.0 Issue

Just a thought did you turn it over a few times with out the plugs before starting during de- winterization to push out any fogging oil from the cylinders this could have caused the plug issue? You could also check all the electrical connection to ensure them to be tight and clean. Hope this helps good luck! post back with results.

 

[Bondo]

Re: Merc 3.0 Issue

I cant decide if it would fall under detnation or not..

Ayuh,... That's what it Is,.... I'd guess the Fuel Filters are plugged up causing it to go Lean at wot...

 

[joey76]

Re: Merc 3.0 Issue

I did not turn it without the plugs during De-Winterization..oops (still learning)
All of the connections look great and fit nice and tight. I will replace the fuel filter along with the plugs in a few days and then try to take it for a test ride later in the week and post the results. Thanks everyone for the feedback..

 

[NHGuy]

Re: Merc 3.0 Issue

If it still acts up with new plugs you can try to check for bad wires by spraying water mist on the plug wires. Bad wires will arc out sometimes if you wet them.

 

[joey76]

Re: Merc 3.0 Issue

Well I think/hope I have found the problem..While getting ready for fresh plugs I started looking a little closer at everything just to be sure I didn't miss something. I started reading the info on the top of the arrestor and noticed the plug gap recommendations..It says 0.045, wait, what? So I pull out my Seloc Manual and flip to the page I had marked for plug gap...0.035 is listed in the book and I know I used the 0.035 as I wrote it down with the date. Any thoughts as to why these numbers are different?

 

[joey76]

Re: Merc 3.0 Issue

Well they sent the incorrect plugs so I am still out of the water. While waiting I have been researching to help ease my mind and now I am wondering if I even have the correct plug to use at all. Here is what I have found...

The plate on my Arrestor says it is Plug AC MR43LTS with a Gap of .045

The Seloc Manual Lists the AC MR43LTS as an Option, but with a gap of .035 as well as an NGK BPR6EFS with a gap of .035 and the Champion (which I used this first go around) also with a .035 gap.

I called Mercruiser and they actually advised me not use the AC MR43LTS with a gap of .045 as listed on the Arrestor and that the NGK BPR6EFS is the most updated with a gap of .035...

I am sooo frustrated and confused...Who thought that changing spark plugs could be such a pain..

Any thoughts guys?

 

[fat fanny]

Re: Merc 3.0 Issue

When I first syarted working on my boat I bought a clymers manul to help with things I didn't know and it did for the most part but I also found out that I have alsolearned to be an editor by owning it meaning that the a,ount of misprints and shadey descriptions are numerous do yourself a favor and go tot he adults only section at the top of this forum and download your manual for free ( thanx to DonS) You will feel more confident with the corect information whan working on your rig and as far as not using AC plugs all I can say to that is nonsence!!!!!!! I would not put anything other than AC in a GM power plant.

 

[bomar76]

Re: Merc 3.0 Issue

The Seloc Manual

Found your problem.

 

[tschmidty]

Re: Merc 3.0 Issue

Yes download the correct manual, but why do we think the incorrect plugs/gap could be causing the clicking at WOT? Just not sure what might be going on to cause that. I could see things like the coil, wires, maybe the distributor advance springs broken and the clicking being in the distributor (have you checked the distributor and/or timing?) but just not sure what the plugs would have to do with the OP's original description of the problem.

 

[joey76]

Re: Merc 3.0 Issue Update:

Re: Merc 3.0 Issue Update:

Update:

I called Mercruiser again today and they stated that I should only be using NGK BPR6EFS with a gap of .035. I talked to my local Bayliner Dealer/Service Dept and they also stated to "use what Mercury tells you to use". I bit the bullet and bought the NGK's..Got home, gapped the plugs, put them in and was off to the nearest lake. It fired right away, let it warm up to normal temp and away I went..I made about four or five passes, all ranges of speed including wot. No Noise, No Loss of Power and it seemed to run smoother than it ever has before..Problem fixed? I hope so...I am planning a weekend long trip for the holiday so I guess time will tell..

Thanks for all of your input and the information on the Manual. I will be downloading that asap.

 

[tschmidty]

Re: Merc 3.0 Issue Update:

Re: Merc 3.0 Issue Update:

Wacky, not sure how that would have caused the noise. Maybe with the too large gap it was grounding to the block externally instead. I supposed that makes sense.

 

[earlandamys180]

Re: Merc 3.0 Issue

I had a very similar problem with my 98 3.0 and I went through it all plugs,wires,cap,rotor button and even a new ignition module and I would take it out and it would seem fine for awhile and then it would rare its ugly head again. It ended up being the 80 amp fuse that hangs on the positive side of the starter that with the vibration of the 3.0 engines the nut had backed off and was laying in the bilge and at times there was good contact (boat ran fine) and bad contact (but ran poorly with ignition noise) replaced that fuse due to arching out so long it messed the threads up and problem was fixed. So if it starts again give that a look.

 

[JaseBosto]

Re: Merc 3.0 Issue

I would say you probably have plug wire issues as well.

Sorry to hijack the thread here, but seeing as we are on the 3.0 subject....

Do they typically run rough? Mine runs rough at idle when cold. Plus it can be difficult to start at all times but runs fine when running.

 

[earlandamys180]

Re: Merc 3.0 Issue

I would say you probably have plug wire issues as well.

Sorry to hijack the thread here, but seeing as we are on the 3.0 subject....

Do they typically run rough? Mine runs rough at idle when cold. Plus it can be difficult to start at all times but runs fine when running.

Yes mine does when cold and kinda ruff when warm but usually starts good after warmed up.I normally let mine run for about 10 minutes with the throttle at about 1200 rpms when I first start it this helps.