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View Full Version : Is it supposed to be like this??



HyperDonzi
04-20-2003, 05:34 PM
This seems a bit bad...WHat all should I do? THis was the only plug like this, the others were fine. #3 cyl. http://www.donzi.net/photos/plug_detonate.jpg

BUIZILLA
04-20-2003, 05:48 PM
I don't know which looks worse...

the plug, or your thumb...

J

BigGrizzly
04-20-2003, 06:34 PM
I would at all cost replace that Thumb. Need to see the others, but I think it is nothing majior. Wait didn't you say you replaced the plugs in the middle of lasty summer. That plug looks a lot older than one summer, due to thr rust and the porceiin color.

smoothie
04-20-2003, 06:50 PM
I gotta agree with BUIZILLA...both are pretty chewed up :D Looks to me like something smacked into it the way that electrode is cracked off.

BUIZILLA
04-20-2003, 07:19 PM
Considering the horror stories I have been hearing lately DIRECTLY from the AC and Champion rep's first hand... I'd say get a new set of Denso's or NGK's in there. Looks almost like detonation from the raggedness of the break.

J

Trueser
04-20-2003, 07:25 PM
So since the thumb is covered.Or should be!

Whats the best spark plugs to use? And plug wires.


Trueser

HyperDonzi
04-20-2003, 07:37 PM
BigGrizzly:
I would at all cost replace that Thumb. Need to see the others, but I think it is nothing majior. Wait didn't you say you replaced the plugs in the middle of lasty summer. That plug looks a lot older than one summer, due to thr rust and the porceiin color. Yep, maybe 50 hours. As I was reading the box for the new ones, got to the part of "resists gap erosion" and my dad started laughing and reminded me of the copper ones we had in there for 2 1/2 years with out breaking like this. Then he asked how hard we ran at the shootout :D :p

The others are ok, look rich, but I figure that is from the fogging oil from winterizing. The gaps on all of them is about .042 from .035

MOP
04-20-2003, 08:35 PM
Hey guy they are right! What a gruesome thumb! Anyway that ugly plug may be an indicator of a problem. Get a new set of decent your choice plugs. Try the following, take it for a run go for about five minutes at 32-3500 RPM then just chop the throttle and shut it down! do not let it idle kill it quick. You want a good plug reading, hopefully all the plugs will be very close in color(real dark tan is sweet) if #3 still looks off you need to do some checking to find out why. bad color on one plug is not a good thing, are the wires new, did this just show up or was it running crappy last year. From the little I can see it looks like the electrode prong was blown off by detonation. Do a compression test they can be off quite a bit cold, you get lousey readings cold. Just see if you are reasonably close to book spec. Let us know what you find.

BillG
04-20-2003, 08:46 PM
I don't think you will get a good plug read unless the engine is under a load.
Bill G

Formula Jr
04-20-2003, 09:16 PM
Yup, first thing, assume the easiest solution.
That being that the plug electrode just broke off cause it was badly made. Compression test #3, as the little part may have scored the cylinder and or exhaust valve seating on its way out.

Formula Jr
04-20-2003, 09:30 PM
Since there's no edit button anymore, I'll continue. The cheap solution is to just replace the #3 with a new plug. What you are showing is a typical over gapped plug that broke its electrode off cause it was fussed with. Been there, done that, got the t-shirt. :D

HyperDonzi
04-21-2003, 07:43 AM
M.O.P.:
Hey guy they are right! What a gruesome thumb! Anyway that ugly plug may be an indicator of a problem. Get a new set of decent your choice plugs. Try the following, take it for a run go for about five minutes at 32-3500 RPM then just chop the throttle and shut it down! do not let it idle kill it quick. You want a good plug reading, hopefully all the plugs will be very close in color(real dark tan is sweet) if #3 still looks off you need to do some checking to find out why. bad color on one plug is not a good thing, are the wires new, did this just show up or was it running crappy last year. From the little I can see it looks like the electrode prong was blown off by detonation. Do a compression test they can be off quite a bit cold, you get lousey readings cold. Just see if you are reasonably close to book spec. Let us know what you find. The plug wires were old...Have a new set to install. The boat was running like crap all of last year, 4600 was the best I could get out of it, Season before nailed 5000. We have the new plugs, wires and rotor cap to install. The plugs are not the cause of it running bad. It was running like that before the plug change.

BUIZILLA
04-21-2003, 07:49 AM
You NEED to do a cylinder leak down test...

You have MORE than a spark plug problem at this point, the plug is the RESULT/SYMPTOM of your problem. In short, it's a CLUE to investigate further.

J

smoothie
04-21-2003, 10:30 AM
You may want to check your air cleaner hardware and make sure its all there,maybe something went down the wrong hole.

Ralph Savarese
04-21-2003, 11:36 AM
Had the same problem but mine was on #5 the compression ratio was too high causing detonation . In my case melting valves also three times this happen before finally
I replaced the Cylinder heads.
I Went back to the old style external bolt heads.
Is this a new motor ?
what heads, Pistons, compression ratio?

HyperDonzi
04-21-2003, 02:35 PM
Bone stock 1990 4.3l Carb motor. Not sure of CR...Im sure those Vortec heads arent much more expensive than the stock ones....

BUIZILLA
04-21-2003, 02:56 PM
Hyper, I had the SAME exact problem on my 1990 4.3 V6 OMC. I ran 36* total with 93 octane for 8 years, and "someone" in my family filled it with 87 for a couple weekends of HARD skiing and burned the tips off two plugs. Electrodes smacked 2 pistons and damaged 2 valve seats... Make sure the TOTAL timing is only 32*-33*, regardless of what rpm the timing maxes at, with 87 octane. Initial should be about 10* @ 700 rpm. The Vortec's do NOT like a lot of total timing on 87 octane. If it's a Merc, look on your module for the degrees of total advance, scribed on the face, and get back to us.

J

been there, did that, bought a 350-310 instead of 2 spark plugs, and 2 valve seats :D

Forrest
04-21-2003, 02:57 PM
Tommy, I would go with BUIZILLA's recomendations on this one. Also notice that center electrode as well. It looks like it's worn at a angle facing what's left of the side electrode. Now, that plug didn't get that way just after your last outing. If you don't have a problem now, you probabaly have one in the works. Also, make sure that those plugs are the correct heat range for that engine as well. Too often, plugs that are too hot somehow find their way into marine engines. Not good.

Rootsy
04-21-2003, 03:12 PM
i think we need a well lit close-up shot of the electrode area... better to see if things melted or if it is mechanical damage...

whatever happened to that thing... i have a gut feeling that you may have injured more than just that poor little champ. all of that metal had to go somewhere!

i'd go with buizilla's checklist first and formost... and check that compression on that cylinder...

DonzigoJR
04-21-2003, 03:31 PM
Hyper,

That is one busted up thumb!!!!! I know you just turned sixteen, so I would be concerned about fixing both the thumb and the engine. Unless your soon to be Donzi girl appreciates the Busted look. :D :D If so, then buy her Mcdonald's for dinner :p , and, put her to work on the boat. As far as the plug, I would agree that this is a indication for further investigation. Try a run with the new plugs, and thrn see what they look like. :confused:

David

Formula Jr
04-21-2003, 05:54 PM
Tommy, you said the other plugs were fine.
Oky. Show us the other plugs, banged up thumb and all. PS. the books are in route - on the slow train.

HyperDonzi
04-21-2003, 08:20 PM
http://www.donzi.net/photos/hyperplug1.jpg

http://www.donzi.net/photos/hyperplug2.jpg

http://www.donzi.net/photos/hyperplug3.jpg

http://www.donzi.net/photos/hyperplug4.jpg

http://www.donzi.net/photos/hyperplug5.jpg

Theres some pics...The busted up one is cylinder 3, the other is cylinder 4 and all the others look like that. How possible is it that the timins slipped some and will that be responsible for a 500rpm loss?

MOP
04-21-2003, 08:40 PM
Pictures are uglier than your thumb, looks like most of the tip is there just blown out straight. I think you got a demon in that engine looks like hot carbon lit off. Did you check compression or lack of yet? Looks alot like one I had that scored the wall and was blowing oil by and lit off was pretty ugly inside needed a bore job and full rebuild.

Forrest
04-22-2003, 09:51 AM
Tommy, you're trying too hard with the camera. Pull back a little, get some GoJo, and don't chew your nails. Those $149 digital cameras don't do so well up close. Better to see an in-focus plug a little farther away than an out-of-focus plug up close.

Terry0341
04-22-2003, 10:57 AM
I hate it when it goes down the wrong hole! :D

Ranman
04-22-2003, 12:16 PM
On a bit of a side note, some cameras have "flower mode". I don't know the actual name, but on my camera the button has a flower on it. Anyway, when you push the button to activate "flower mode" the focal point is about 9" from the subject. This means hold the camera 9" from the plug and take your pic. It's amazing (on my camera at least) how much better the close-up pics come out.

MOP
04-22-2003, 07:09 PM
Macro setting for super close ups :D