Merc plug substitution? please help......

[petryshyn]

Hi gents:<br /><br />I have a 1978 70HP 3cyl. long shaft merc. S#7087833 or S#4994955 (for our US friends)<br /><br />Maybe I'm old fashioned, but I hate the perma-gap plug recommended for this engine.(L76V)<br />>Is there enough clearance to run a conventional plug? Has anyone tried this? Is it documented anywhere? If a different plug is used, are the heat ranges compatable?<br /><br />Please....any comments??

 

[Ross J]

Re: Merc plug substitution? please help......

Hi, Ho Schematic,<br />Is this one of the "Blue Band" outboards?<br />If so then I believe there is indeed a substitute in the short plug range. We used to run shorts in a 90hp "Blue Band" motor that came with those new fangled things you mention. I'm sorry, for the life of me I can't recall the type or number. Somebody is bound to know this info.<br />Regards<br />Ross

 

[Rex]

Re: Merc plug substitution? please help......

IT MUST BE A 78 CAUSE THE NUMBER START AT<br />4825249 AND YOUR ID IS 4994955.<br />I WOULD GO WITH A CHAMPION PLUG AND YOU<br />CAN GO 1 HEAT RANGE HIGHER. JUST TO KEEP<br />THE PLUGS CLEANER.<br />GOOD LUCK<br />REX A HUBBLE

 

[PurpleDragon]

Re: Merc plug substitution? please help......

While we're on the subject of spark-plugs, I've been trying to locate replacements for my Champion H8J plugs.<br /><br />I've looked at several sites, including the Champion site, and can't find reference to the "H" family of plugs by Champion. <br /><br />I'm presuming that the particular one is not manufactured anymore... Does anyone know a part number for a replacement? (or a pointer to a site that would help us all?)<br /><br />Thanks,<br />Rex S.

 

[DP]

Re: Merc plug substitution? please help......

Rex<br /><br />Looks to me that it would now be a Champion H8C or NGK B6L

 

[Trent]

Re: Merc plug substitution? please help......

Check out WWW.clubplug.net look around the site a little and do some cross matching you might find what your looking for??

 

[petryshyn]

Re: Merc plug substitution? please help......

Trent:<br />There are cross-overs available, but I'm looking for different electrode style. The OEM is a perma-gap, and I want a conventional electrode. Any thoughts??<br /><br />

 

[Trent]

Re: Merc plug substitution? please help......

Yes I understand and have seen this before...Let me get the old brain back in gear! Their is a cross over if I remember correctly.. I will get back to you on it. <br /><br />What is your problem with the perma-gap? They have worked well for me!! You got a problem? <br /><br />You still in the I want to gap a plug mode?? <br /><br />Heck It took me ten years to get away from points, plugs, and condensors on my old truck...<br /><br /><br />Guess im getting old..Just turned 41 last week.

 

[mbb]

Re: Merc plug substitution? please help......

My old merc 90 uses the L76V with no problems. But when I got it it had AC-M44C plugs on 3 of the cyls, and it ran fine (these are conventional electrode). Ive never seen another cross reference though for any plug other than the NGK BUHW.<br /><br />P.S. Thanks for the education.

 

[Hooty]

Re: Merc plug substitution? please help......

Spec's for my Evilrude call for a UL77V surface gap plug but I've been running L77J4's without problems.<br /><br />c/6<br /><br />hooty

 

[Stream_fisherKY]

Re: Merc plug substitution? please help......

Can anyone tell me what the proper gap size is for a 76 model 9.9 evinrude. I am having trouble keeping plugs alive in my engine and i am looking for answers to the problem. I have considered the coil as the source but i wanted to make sure i'm using the right plug/gap to eliminate that from the list of potential causes.

 

[petryshyn]

Re: Merc plug substitution? please help......

Thanks to all who responded. Keep the comments coming if you think of more....<br /><br /><br />Hi mbb:<br />Thanks for the number!! I'll check that out!!<br /><br />Hi Trent:<br /><br />The problem I have is when I leave her sit for a week or two, she miss fires when first started up. She clears only with WOT in gear. Then she's good for the rest of the day, even if she's allowed to cool completely. If I use her everyday...no problems, I can go the season without changing plugs. If I let her sit for a week or 2, I'll change plugs 2 or 3 times a season. Its done this as long as I've had it (10 years). Had some free time, so I decided to find out why. Pulled the plugs several times before starting it and found that oil accumulates in a little puddle between the center electrode and ground. If I wipe this off before starting it.....problem solved. I believe its just the shape of the area that allows oil to settle in on. I've tried a hotter heat range......no change. I've used 3 different oils (even ran 100:1 for awhile) same thing. It also may have something to do with me storing my boat in a drive-in boat-house. I never have to tilt the engine up, and I'm not going to just to please a permagap. Tilting it would probably prevent this accumulation but..... I'd rather put in a better plug. I'd appreciate the cross you say you've seen....thanks<br />

 

[petryshyn]

Re: Merc plug substitution? please help......

Stream_fisherKY <br /><br />UL81J set at .030"

 

[Stream_fisherKY]

Re: Merc plug substitution? please help......

Schematic:<br /><br />Thanks for the info. you've been really helpful. I am trying to find that cross for you but so far no luck. Will let you know as soon as i come across it.

 

[BRG25]

Re: Merc plug substitution? please help......

NGK has a cross reference in Excel format you can download if it helps.<br /> http://home.att.net/~ngkaz/wsb/html/view.cgi-home.html-.html

 

[petryshyn]

Re: Merc plug substitution? please help......

Trent.......any luck?

 

[petryshyn]

Re: Merc plug substitution? please help......

bump