What would cause this ?

« **on:** May 29, 2015, 11:52:29 PM »

After getting my starter issue figured out the engine would not idle at all... Checked plugs and found plugs for cylinders 6 & 8 missing the center electrode.. These were AC delco plugs gapped at .035. Engine temps was around 150... All other plugs were fine...I've never had this happen before so I'm wondering what would have caused this...

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« **Reply #1 on:** May 30, 2015, 07:43:45 AM »

Detonation causes that.

So that means those cylinders were lean for some reason.

« **Reply #2 on:** May 30, 2015, 10:57:13 AM »

Would detonation be caused by improper timing? Too advanced or too retarded

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« **Reply #3 on:** May 30, 2015, 11:08:44 AM »

Quote from: Handyman on May 30, 2015, 10:57:13 AM

Would detonation be caused by improper timing? Too advanced or too retarded

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one of the reasons

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« **Reply #4 on:** May 30, 2015, 11:25:33 AM »

Timing, vacuum leaks, carb issues, oil blowby, low octane fuel, and carbon build up can all cause this.

« **Reply #5 on:** May 30, 2015, 11:49:33 AM »

I would do a compression check. That core went somewhere.

What do the other plugs look like?

« **Reply #6 on:** May 30, 2015, 12:45:15 PM »

All the other plugs looked fine..looked like the 2 posted in the pics color wise.. Went and got NGK plugs. Will check timing today.. Where should the timing be?

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« **Reply #7 on:** May 30, 2015, 12:54:49 PM »

Quote from: Handyman on May 30, 2015, 12:45:15 PM

All the other plugs looked fine..looked like the 2 posted in the pics color wise.. Went and got NGK plugs. Will check timing today.. Where should the timing be?

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A good starting point is about 35° btdc at above 2,500 rpm. But it depends on what you have for advance built in to the distributor.

What exhaust system do you have? Reversion could do this as well, those cylinders are buddies. Might be something bigger going on.

Compression check should be first on the list. Make certain the throttle blades are wide open when you do the test. Many forget this step.

Good luck.

« **Reply #8 on:** May 30, 2015, 12:59:47 PM »

I have no clue how Much advance I have built into the distributor... The previous owner couldn't tell me much about the motor... But I think he knew more than he was wanting to tell me... If I can get this motor to run for the summer I will rebuild it over the winter. I have a couple spark plugs threads on the verge of being stripped so I'm cautious of how many times I take out and replace the plugs

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« **Reply #9 on:** May 30, 2015, 03:06:28 PM »

Quote from: Handyman on May 30, 2015, 12:59:47 PM

I have no clue how Much advance I have built into the distributor... The previous owner couldn't tell me much about the motor... But I think he knew more than he was wanting to tell me... If I can get this motor to run for the summer I will rebuild it over the winter. I have a couple spark plugs threads on the verge of being stripped so I'm cautious of how many times I take out and replace the plugs

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Super easy to find out your timing curve. Put the timing light to the motor at idle, once you have that number all you do is bring your RPM's up and watch it as the timing advances. When it stops, you subtract the idle timing from that number and you've got your timing curve.

For example, at idle, my motor will show 15* timing, at around 3000rpm my timing stops advancing at around 36*. I have 21* of timing advance. Once you find that number, you can time the motor at idle by just adding the 21* to whatever your idle timing is. Example, if you have 20* of timing advance, and you're shooting for 35* total timing, you'll set your idle timing at 15*.

« **Reply #10 on:** May 30, 2015, 04:57:51 PM »

I'm calling it quits on this damn boat.. I can't get it to idle for the life of me... The carb keeps filling up with gas and dies out. I can't time it due to it not idling, and when spark plugs start popping out of their holes... When I put the new plugs in I thought I felt one strip but it snugged down... When the plug popped out I went back and found all but #2 plug were all stripped.... Can't even do a compression check.

I thought the seller was hiding something when I asked about the motor.. When I first asked about the boat he instantly said that he knew nothing about it. He got it on a trade... He said he started it a few times etc... I think the fact that the interior was brand new and the hull was in over all great condition blinded me on the motor... I've been working on it the past few days and have found a bunch of jury rigged crap...I dropped everything I had saved on the purchase of the boat and have nothing left to get the heads repaired and the motor tuned/ rebuilt. So it will be a great lawn ornament for the rest of the summer....

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« **Reply #11 on:** May 30, 2015, 05:05:24 PM »

Carb filling with gas? U mean the boosters are leaking fuel at idle?. Thats a float level or poop holding the needle n seat open issue..

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« **Reply #12 on:** May 30, 2015, 05:21:09 PM »

Quote from: aquaholic72 on May 30, 2015, 05:05:24 PM

Carb filling with gas? U mean the boosters are leaking fuel at idle?. Thats a float level or poop holding the needle n seat open issue..

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Once it starts and the idle starts to come down the front bowls on the carb starts to fill up with gas and then does out.. I don't know crap about carbs...but that's least of my worries...

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« **Reply #13 on:** May 30, 2015, 05:31:45 PM »

Quote from: Handyman on May 30, 2015, 05:21:09 PM

Once it starts and the idle starts to come down the front bowls on the carb starts to fill up with gas and then does out.. I don't know crap about carbs...but that's least of my worries...

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ya ur needle n seat probably has shit in it...but ur right, thats the least of ur worries... sorry brother...

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« **Reply #14 on:** May 30, 2015, 05:45:22 PM »

U probably should pull the heads, have them gone thru, plug threads fixed.. only good advice i can give is dont get frustrated, i know thats hard, but its part of bein a boat owner...something is allways gonna pop and smack u in face..frustration fixes nothing.... good luck..

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« **Reply #15 on:** May 30, 2015, 06:01:17 PM »

None of that sounds very serious, maybe two weekends worth of work (cruising). Don't get discouraged!

There are spark plug thread repair kits that you can use with the heads still installed. Put some grease on the tap to retain the metal chips so they don't fall down inside the engine.

Even if you have to pull the heads, assuming you don't have problems with the valves, you would only be into it for a set of gaskets.

Could you pull a valve cover and post up the casting numbers? If they are nothing special, even worse case scenario, shouldn't be expensive to fix.

I am assuming you have a Holley carb from your description. They are easy enough to rebuild (if necessary). Pick up the appropriate Holley Trick Kit and with just some basic hand tools, I am sure you can get it dialed.

I would say bring it by my shop and I would help you wrench on it, but I am about 200 miles south of you.

Time to man up and earn your namesake. Keep us in the loop and rough times will quickly be a thing of the past.

Cheers,

Joe

« **Reply #16 on:** May 30, 2015, 06:11:54 PM »

I did not know there was a spark plug thread repair kit.. Yes it's a Holley carb but I have no idea what size it is... I had to take a break from working on it.. I would pull the heads but I have no idea what the torque sequence is and I know there is a special sequence..

I will get this bastard figured out...just extremely frustrated right now..

Is there a stamping on the carb that say is what size it is?

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« **Reply #17 on:** May 30, 2015, 06:23:27 PM »

Quote from: Handyman on May 30, 2015, 06:11:54 PM

I will get this bastard figured out...just extremely frustrated right now..

« **Reply #18 on:** May 30, 2015, 06:26:48 PM »

List# on the choke horn.. tell us what it is, we can get u alil info..

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« **Reply #19 on:** May 30, 2015, 06:28:42 PM »

Quote from: Handyman on May 30, 2015, 06:11:54 PM

Is there a stamping on the carb that say is what size it is?

There are numbers on the choke shroud, but I don't know how to interpret them. There are a few carb gurus here that I am sure can tell you exactly what you have right off the top of their heads.

There are a few numbers, if you post them up, somebody will chime in or I will look them up when I get home.

« **Reply #20 on:** May 30, 2015, 06:38:26 PM »

Here are a couple pics of the carb

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« **Reply #21 on:** May 30, 2015, 06:44:32 PM »

Quote from: Handyman on May 30, 2015, 06:11:54 PM

I would pull the heads but I have no idea what the torque sequence is and I know there is a special sequence..

You're going to want to seal the head bolt threads on reassembly to prevent migration of water up the threads and into the oil. We also put a bead of blue Permatex in the fillets under the heads of the head bolts for redundancy.

« **Reply #22 on:** May 30, 2015, 08:06:14 PM »

Quote from: Handyman on May 30, 2015, 06:38:26 PM

Here are a couple pics of the carb

Look around on and near the choke shroud for some numbers. It's a dual feed double pumper and worth rebuilding.

« **Reply #23 on:** May 30, 2015, 08:27:11 PM »

Here is the carb numbers

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« **Reply #24 on:** May 30, 2015, 08:34:24 PM »

And the head casting numbers

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Handyman

philofab

Handyman

jimpen

philofab

GT Jets

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crazyjim

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aquaholic72

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aquaholic72

aquaholic72

Flusher

Handyman

Flusher

aquaholic72

Flusher

Handyman

Flusher

Flusher

Handyman

Handyman