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Author Topic:   Sparkplugs for Merc 150 Optimax
wenchris posted 10-11-2003 04:09 PM ET (US)   Profile for wenchris   Send Email to wenchris  
I seem to be a little confused, the owners manual recommened NGK plugs. It states for severe duty: NGK #PZFR5F-11,@ $12.00 a pop, for light duty NGK #ZFR5F-11@ $4.00 a pop. Merc Dealer says to use only the new NGK Iridium plugs @ $14.00 a pop. I Am Confused ??? Can someone clear this up so I can get my Whaler back in the water. Thanx Jimmy
dauntlass 18 posted 10-11-2003 07:43 PM ET (US)     Profile for dauntlass 18  Send Email to dauntlass 18     
I use NGK pzfr5f-11 in my 200 hp Optimax.That is what the Mercury shop manual calls for.Try may have some information on various Ngk plugs and maybe better prices.I think iridium may be a replacement for the platinum plugs mentioned above.
jimh posted 10-12-2003 12:08 AM ET (US)     Profile for jimh  Send Email to jimh     
I recently ordered from Their prices are good and the shipping is very good ($4). The plugs are sent from Quebec; it takes about 10 days.
wenchris posted 10-13-2003 11:17 AM ET (US)     Profile for wenchris  Send Email to wenchris     
Thanks good prices on once again this forum pulls through.
BillD posted 10-23-2003 05:07 PM ET (US)     Profile for BillD  Send Email to BillD     
I was actually speaking with my Mercury service department today about winterizing my motor and they mentioned that it was time for new plugs and they were recommending the new NGK Iridium plugs. So I asked why. The new plugs are supposed to help in the Optimax engines for owners that idle or troll frequently. I believe they said they helped reduce carbon build up. I'll ask again when I drop off my boat.
wenchris posted 10-23-2003 10:02 PM ET (US)     Profile for wenchris  Send Email to wenchris     
Thanks just ordered some from paid $12.69 each. Free shipping,cheaper than Merc dealer Jimmy
walleye seeker posted 04-15-2004 04:40 PM ET (US)     Profile for walleye seeker  Send Email to walleye seeker     
I noticed this post when I was searching for a good deal on the PZFR5F-11 NGK spark plug. I know it's old but, I found
these plugs at for $9.98. There part number is 4363. Can be ordered on line.
skategoat posted 04-15-2004 04:45 PM ET (US)     Profile for skategoat  Send Email to skategoat     
Margins are better on the iridium plugs or the dealers buy into the marketing. My experience from 20 years of mucking with old cars - go copper and change them frequently.
lakeman posted 04-16-2004 02:38 PM ET (US)     Profile for lakeman  Send Email to lakeman     
I just bought the PZFR5F-11 NGK at advance auto parts or the old discount auto parts store for $10 amd the manager felt sorry for me and gave me a 5% discount on top of that.
I guess this might be for Florida people, I do not know if they are out of state.
walleye seeker posted 04-19-2004 06:11 PM ET (US)     Profile for walleye seeker  Send Email to walleye seeker     
I have six PZFR5F-11 NGK's. One is new the other five have 49 hours on them. All are excellent condition (one new) I will sell the bunch for $30 plus ship. I replaced these with new ones and when I took them out they were as good as the new ones. Could hardly tell the diff. Replaced them anyway. No diff on engine running. They all worked fine.
bsmotril posted 04-20-2004 12:35 PM ET (US)     Profile for bsmotril  Send Email to bsmotril     
Copper Plugs in an Opti motor will last you at most 50 hrs if you're lucky, and less if you run at the upper end of the stratified charge range around 2800 rpm. Plus, they are not the easiest to change unless you have u-joint socket adabpters, or wobble socket to get to the bottom plugs. On an opti, the platinum plugs make sense and will easily last 100hrs. I got close to 200 hrs on my last sets.
sportroyalwulf posted 04-20-2004 01:30 PM ET (US)     Profile for sportroyalwulf  Send Email to sportroyalwulf     
This is my first year of un-winterizing my motor (60 hp bigfoot). The owners manual specification called for Champion plugs. I went to a mercury dealer and he said that NGK was the reccomended plug to use. Normally my choice would probably be something other than the champ. I asked if he had any service bulletins etc. that would explain that NGK was the reccomended choice. My position is that as long as this thing is under warranty, I will be installing exactly what is reccomended (in writing) by mercury. My belief being that any excuse to not do warranty service will be quickly exercised by a dealer and mercury. He could not produce any factory literature that indicated that the NGK was a requirement. I bought the champs.

Similar experience not related to plugs. The factory specs say to use 10w30w mercury/quicksilver oil for all around and 20w50 for more severe conditions. The store I went to was out of the 10w30 as there was a lable on the shelf indicating that at one time they carried the product. This guy told me that the recomended oil was the 20w50 and that they did not even make 10w30. It is local business operations like this that make mail order look much better.

bsmotril posted 04-27-2004 11:45 AM ET (US)     Profile for bsmotril  Send Email to bsmotril     
One other thing to note about plugs. The threads on the NKGs have rolled edges, versus very sharp edges on the the Champions. On an aluminum cylinder head, the roll edges are less abusive to the threads in the head. They also better allow for coating the threads with anti-seize and actually having some of it stay in the thread area.
jimh posted 04-28-2004 01:03 AM ET (US)     Profile for jimh  Send Email to jimh     
[Please note that the most recent comments to this thread were posted in April, 2004]

Bills--Thanks for the information on the NGK plugs and their threads.

Regarding the Optimax spark plug change on a V-6 block like the 2.5-liter 150-HP engine: I recently was looking closely at one of these and it appeared that removing the plugs would be a bit of a project, particularly for the lowest plug on the port side of the engine.

Is it necessary to remove any other engine component to get access to the plugs for changing them? (Of course, I understand you have to remove the ignition wire and boot!)

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