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Originally Posted by SB
(Post 4845731)
Looking thru my phone my eyes went to cyl #6 for now.
Appears to me like many pepper marks. ”Detonation shows up on the plugs as spotting on the porcelain. There are two different types of spotting seen. One type appears as just black spots and the other appears as little bright spots like diamonds. The black spots (look like pepper sprinkled on the plug) indicate a little too much heat on the plug which causes detonation by having the heated plug fire off the mixture prior to the spark firing. This creates two flame fronts that collide and can cause great amounts of damage. If you see black spots on the porcelain and you know the tune-up is correct then you may need a colder plug. If you are not sure then increase the carburetor jet size slightly, take out some timing, or go to a colder plug. If you hold the plug in the sun and you see what appears to be small diamonds on the porcelain then your detonation is severe enough to be blowing off the aluminum from your piston and you need to add fuel and/or take out timing now.” 8 7 6 5 4 3 2 1 |
Originally Posted by boostbros
(Post 4845868)
those 2 black plugs are something wrong wires not on correct cyl? cam firing order swap? black and wet is not firing
I checked wires before my last outing and #2 almost didn't feel like it was on good. I was hoping for an improvement, but no change. I will verify the firing order again to rule that out. The boat feels down on power from what I would expect and the timing is all out of whack. You'd think this place would want to get me in. I even told them I'd pay labor if everything checked out. For F*CKS sake. You don't think it's firing at all on those two cylinders? |
Originally Posted by boostbros
(Post 4845868)
those 2 black plugs are something wrong wires not on correct cyl? cam firing order swap? black and wet is not firing
Originally Posted by ThisIsLivin
(Post 4845854)
How old is the balancer? They set the timing before doing any hard dyno runs and the ring could have slipped and now reads 40. Get a piston stop and check your timing mark. 3924 is recommended by AFR for Pump Gas, I run them in my motor and they are not too hot based on the ring on the electrode. But my motor runs super cool anyway. You definitely have some distribution issues. Even bank looks a little rich across the board with 4 and 7 really fat. I would try a 1" tapered spacer with a 1" open to try and get better distribution. When I pull my plugs you can't tell one from the other and I'm running a custom 1000CFM 4150 on a Brodix HV2000 intake with both spacers I mentioned.
I may actually have an old HVH super sucker I ran on my car years back. I'll see if I can dig it up and give that a try. BTW I have the plugs facing like you're looking at the engine, so it's the odd bank and #2 and #5. Not that it really matters, issues at the end of the day. 8 7 6 5 4 3 2 1 Appreciate all the advice man! |
Originally Posted by SB
(Post 4845874)
I just got a look with little better video screen at #6 plug and it’s really concerning.
8 7 6 5 4 3 2 1 Amazing this thing was apparently dyno tuned too. |
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Originally Posted by SB
(Post 4845926)
does the ground electrode show anything that would also mimic detonation? |
Glazing on porcelain shows rich at idle.
Black specs show detonation typically from too hot plugs and/or timing. More detonation would show up as tiny aluminum balls down towards bottom of porcelain. You need a good kight snd sometimes magnifying glass to see it. I’d set total timing to 34. I’d run a colder plug. The autolite 3923 or ngk bkr6e. Maybe even bkr7e for now to play it safe ? Gap any of these to .035”. btw: slightly off topic, but since it will be effected when you change total timing, what is your initial timing ? |
Go to Walmart and get yourself an Otoscope in the pharmacy department for checking your plugs. Best money I ever spent. If you had 2 cylinders not firing you would have a hard time getting on plane and it would shake something terrible. What ignition are you running and what wires? Check the jets on the carb to see if they are the same on both sides as well.
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Originally Posted by ThisIsLivin
(Post 4845941)
Go to Walmart and get yourself an Otoscope in the pharmacy department for checking your plugs. Best money I ever spent. If you had 2 cylinders not firing you would have a hard time getting on plane and it would shake something terrible. What ignition are you running and what wires? Check the jets on the carb to see if they are the same on both sides as well.
Shop just text me back and said: "if the plugs look like this after normal boating then they're fine. It's a carburetor with a big plenum." |
I find a spark plug magnifier is a great tool to see the plug but I still don`t know what I`m looking at .
I thought the ground strap tells the timing story ... https://cimg6.ibsrv.net/gimg/www.off...0bed11a11f.jpg |
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