Problems Changing Plugs 1990 Mercruiser

[shelikesit]

I just bought a 1990 Galaxy with a V-6 mercury inboard motor. I ran the junk gas that was in it because I didn't know any better.<br /><br />Now, since I have the tank spotless, new filters, new gas, I have no spark.<br /><br />It looks like I fried a couple plug wires that were close to the starter that I'm sure I got quite hot trying to start the thing with bad gas in the first place.<br /><br />Question is, I'm changing everything that has to do with the spark but can't get to the plugs.<br /><br />Do you really have to take the exaust manifold risers off this motor to change the plugs???? It sure looks like it. The tips of the plugs are very close to the manifold, so close that a socket can't get around it.<br /><br />Plus, the plugs are so deep in the head, you can't get a box wrench on any of the plugs. I know I need the manual but it's coming. In the meantime, I'm sure the no spark has something to do with the burnt wires, but what about the plugs, how do you get them out?<br /><br />It's Thanksgiving or I'd already have the wires, cap and coil changed. I believe the ignition module in the distributor may need to go too.<br /><br />Thanks, and sorry for clogging your brain.<br /><br />HAPPY THANKSGIVING !!!

 

[Don S]

Re: Problems Changing Plugs 1990 Mercruiser

I have no idea how you get to the plugs on your particular boat, I doubt anyone else will unless they know the model number of your boat.<br />Many manufacturers make it almost impossible to access needed maintenance items. Have on Campion that comes in every 3 or 4 years (When it quits running) because it has to have the engine removed to get to the spark plugs.<br />What ever you have to do to get to those plugs, you might as well change the starter. When they get so hot they melt plug wires, they have very little life left in them, and you really don't want to have it go bad on you out on the big water.<br />You might also want to look into some manuals for your engine and drive. Get the OEM Mercruiser manuals, not the Seloc or Clymers.

 

[Bondo]

Re: Problems Changing Plugs 1990 Mercruiser

Mines a 1990something 4.3LX Mercruiser,........<br /><br />Ayuh,.... Things are Alittle Tight,...... But,...... I've always used a Socket on Mine............

 

[shelikesit]

Re: Problems Changing Plugs 1990 Mercruiser

So I can get on top of the plug with a socket? It looked as though if I even tried it would break the ceramic.<br /><br />I did notice carbon buildup falling off from what looked liked a "rounded" area where each plug and boot go. Does this make sense maybe. Clean up some rust and carbon and I should, or "may" have room to get a socket on it.<br /><br />Thanks for your help, come morning I'll try to get a socket on. I really couldn't imagine having to remove the risers to remove the plugs, but from this purchase, I'm ready for anything.<br /><br />I love the boat, it's a 22ft cutty, but it ran wonderful for 10 minutes, then everything went to putz. I narrowed the initial problem down to bad gas and sludge, that's what I found when I went into the tank last night, bad gas and sludge.<br /><br />Thank You.

 

[shelikesit]

Re: Problems Changing Plugs 1990 Mercruiser

THANKS DON, was going for the clymer, but I appreciate the about face on that!<br /><br />The boat is a 1990 Galaxy model 228

 

[Don S]

Re: Problems Changing Plugs 1990 Mercruiser

If you have just a "Break the Plug" problem not get a getting to it problem, then you may just have to modify a sparkplug socket.<br />Also, do NOT use Champion spark plugs. They are longer and break very easily. Use either NGK, AC, or Bosch plugs which are shorter and less prone to breakage.<br /><br />

 

[tashasdaddy]

Re: Problems Changing Plugs 1990 Mercruiser

dan, i had the same problem. i took all the seats,upolstery out so you can have a goog work space, i laid down on the floor and with a 6-8 extenion was able it see the plug and work the socket on. you need a good flash light to get the new one in.

 

[shelikesit]

Re: Problems Changing Plugs 1990 Mercruiser

Thank You to all of you. I just couldn't believe you'd have to do 6 hours of remove and replace to do a 30 minute job.<br /><br />Don,<br />That grinding of the socket is all me, thanks. I sat for an hour or so trying to figure how to make a tool to do this.<br /><br />That idea never came to mind. I was ready to cut and bend a combination wrench but the plug sits too close to the head to get even that on.<br /><br />A grinding I will go, THANKS!

 

[Don S]

Re: Problems Changing Plugs 1990 Mercruiser

Break the old plugs off, and use the shorter plugs I mentioned when going back together. They will fit.<br />Bet if you look at the old plugs, they are Champions. The only ones I know that were THAT long.

 

[shelikesit]

Re: Problems Changing Plugs 1990 Mercruiser

Just break em off eh? Not a problem.<br /><br />I have the BR6FS NGK in hand. I'll go spray the ones in there down now with PB Blaster so in the morning, hopefully they'll just break loose and I can be on my way to getting my spark back.<br /><br />Inexperience bites, but it's worth sooooooooooooooo much in the long run.<br /><br />My next boat will be stripped of gas as soon as it gets home. Running what was in it caused all of this. The boat planed out and was heading to the inlet just fine, as soon as the sludge broke loose so did the "just fine"<br /><br />Thanks Again!

 

[shelikesit]

Re: Problems Changing Plugs 1990 Mercruiser

The NGK plugs are gapped @ .030 I was told to increase this to .040<br /><br />Does this sound right?<br /><br />Thanks

 

[DHPMARINE]

Re: Problems Changing Plugs 1990 Mercruiser

I've been using braille to replace sparkplugs for years,but never had it correct a no spark problem.<br /><br />Am I missing something here ?<br /><br />DHP

 

[seahorse5]

Re: Problems Changing Plugs 1990 Mercruiser

SnapOn has come out recently with a new "shorty" 5/8" spark plug socket for limited access situations.

 

[Weirdwalt]

Re: Problems Changing Plugs 1990 Mercruiser

You can grind them down like that or sometimes you and get a wobbly on the hex on the end of it. All you have to do is break it loose then you can get a plug boot on it and unscrew it.

 

[shelikesit]

Re: Problems Changing Plugs 1990 Mercruiser

DHP, your on the money.<br /><br />Braille was it, and still no spark is it also.<br /><br />Today took 6 plugs, new wires, rotor, cap, rewired starter, and a deck wash.<br /><br />Still no spark.<br /><br />Tomorrow may bring a coil, ignition module and a couple new nerves to burn.<br /><br />Thanks for all the help, DonS, your were right, champion plugs where there. Your pretty darn astute to the game.

 

[Don S]

Re: Problems Changing Plugs 1990 Mercruiser

"Astute" hmmmmmm. Never called that before. <br />I work on these darn boats for a living, so I have seen it before, many times.<br />It's time to STOP throwing parts at it and find out the problem.<br />You need to get a VOM or DVM to check the ignition system. Make sure the lanyard is installed in the kill switch and the switch works then go through the following troublshooting chart.<br /><br />

<br /><br />One note about the chart, the ignition module and the ignition sensor are NOT the same item. Many people make that mistake and order the wrong thing.

 

[SeaRay24Sorrento]

Re: Problems Changing Plugs 1990 Mercruiser

A tip to get new plugs started: Cut a length of rubber hose and slip it on the small end of the plug, now u have a long flexible u-joint to get them started and finger tight, then pop it off and snug it up. Worth shopping for a new spark plug socket, some are bigger than others on the outside. The small one I got has some grinding on the ends and has worked in just about every application. A modified 3/8" extention with a wobble end helps as well. Get a grindin'. Was able to do an easy compression test this way on my '88 Merc. 4.3l.

 

[shelikesit]

Re: Problems Changing Plugs 1990 Mercruiser

Hey thanks for everything from everyone.<br /><br />Don S. a question for you about the mercruiser ignition thunderbolt 5. The ignition computer on the triangle mount, 1990 model, there's a solid black wire with a small ring on it. It's just dangling there. It's the only solid black wire coming from that plug. That $300 plug from I found out, and hope I don't have to replace. It's the main brain and the only part left that I haven't changed.<br /><br />I just got funds revived and got a voltometer and your diagram printed. I'm going out to put the last 2 parts on. The ignition sensor and starter voltage regulator.<br /><br />I replaced the coil, plugs, rotor, cap, wires, starter amd have the ignition sensor left. I'm glad all this happened, if it ran right from the get go I would of spent my money on bait and gas. This way I'm getting to know the motor up close and personal and you'll be able to eat off it from the fan belt to the bulkhead before the rest of the boat sees a car wash.<br /><br />Thanks to everyone for the help, to my amazement I used a bit of everyone and everything went well.<br /><br />So, to reiterate, I have a solid balck wire coming from my main brain dangling, and just incase anyone is froggy, there's a blue and white one coming from the other side of the motor just dangling also. It's part of 2 wires, the other goes to a manifild sensor, a bubble shaped devise mounted to the manifold I think.<br /><br />Thanks a ton, I may have spent but you guys saved me a ton.

 

[Bondo]

Re: Problems Changing Plugs 1990 Mercruiser

So, to reiterate, I have a solid balck wire coming from my main brain dangling, and just incase anyone is froggy, there's a blue and white one coming from the other side of the motor just dangling also. It's part of 2 wires, the other goes to a manifild sensor, a bubble shaped devise mounted to the manifold I think.

Maybe,........ This will Help,...................

 

[shelikesit]

Re: Problems Changing Plugs 1990 Mercruiser

It looks like it mounts to the distributor, is that possible,<br /><br />MANNNNNNNNNNNNNNNNNNNNNNNNNNNN THANKS ALOT FOR THAT LINK !!!!!!!!!!!!!!