Doing a Tune Up on my 2000 Merc 4.3L

JimKW

Petty Officer 1st Class
Joined
Jul 10, 2009
Messages
397
Finally decided to start doing some stuff myself on my 2000 Crownline 180BR. It's been running a little rough when I first start it so I thought I'd do a tune up. I've had for just over two years and thought it might have the original plugs in it. It was a chore to get to the plugs because somebody put all stripped headed screws to hold down the cover that goes around the engine. Once I got that off getting the plug out was a pice of cake. I spent two hours getting the cover off though. I will put new screws in with good heads because that should not have taken more than 10 minutes.

Well when I took the plug out it's an NGK R BPR6EFS. I'm assuming they have been replaced at least once since it's not an AC Delco and the plug looks fine to be honest, but I will replace them anyway. Wires and cap look fine so I probably won't even bother taking the Distributor Cap off. Just put in a new set of plugs.

The sticker on the flame arrestor says to gap them at .045. Is that what most people gap them at? Should I get AC Delco or just get another set of NGK's? It's been running fine so I don't have any complaints. Just kind of felt like doing something to it on a cool day.
 

Don S

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Aug 31, 2004
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62,321
Re: Doing a Tune Up on my 2000 Merc 4.3L

The sticker on the flame arrestor says to gap them at .045. Is that what most people gap them at?

What's the difference what others set there's at, yours is supposed to be .045 so why wouldn't you set them at that????

The NGK plugs are fine, but if you get new ones, get the BPR6EFS-11 plug. The -11 indicates the larger gap
 

soonerce

Cadet
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Aug 4, 2012
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11
Re: Doing a Tune Up on my 2000 Merc 4.3L

I just changed the plugs in my 2007 180BR and I gained 600 RPM at WOT.

I went with AC Delco MR43LTS. They are marine grade plugs, but I'm not sure if that is just a gimmick or not. They only cost me $3 a piece though. I set their gaps at 0.045 as recommended. The existing plugs were Delco also but not the MR43LTS as recommended by Mercruiser. They weren't fouled to terribly bad, but one was set with such a small gap it may have been shorted.
 

JimKW

Petty Officer 1st Class
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Jul 10, 2009
Messages
397
Re: Doing a Tune Up on my 2000 Merc 4.3L

I went with the AC Delco MR43LTS plugs also, and I gapped at .045. They did not have the NGK's in stock. I have not started it yet though. Too much trouble to pull the boat out of the garage, put the muffs on, start it up and then put it back in the garage. I don't see any reason why it would not start, so I'll just wait until tomorrow when I can take it out. If for some reason it would not start I would be bummed out, but would not want to work on it any more today. Which is another reason to wait.

Oh I don't know why I asked about the gap, but on my Volvo it's recommended to gap it different than what the specs say and I don't remember why.

I have to admit it does feel pretty good to finally do something on the boat myself. Like I said doing the plugs was a piece of cake, but getting the cover off from around the motor was a pain mainly because of what the last owner did when he stripped the heads on the screws.
 

JimKW

Petty Officer 1st Class
Joined
Jul 10, 2009
Messages
397
Re: Doing a Tune Up on my 2000 Merc 4.3L

Just an fyi if somebody is reading this. It ran good, but the lake was very choppy so I never got to WOT. The main difference I noticed was that it seemed to start much quicker when it was cold. I think it was probably a little smoother at idle when it was first started. It always ran fine once it warmed up.
 
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