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Discussion Starter · #1 ·
Hey friends,

My old 65 mustang (V8 289 with a new holley carb) is in trouble.

It was driving great for a year or so. A few days ago it had trouble starting. When it did start, it had a very rough and uneven idle, and very low power when driving - like it wasn't running on all 8 cylinders, felt like.

When i revved it in idle, it backfired and a lot of black gunk shot out of the exhaust (picture of the gunk on my driveway included).

It then idled OK, but there was A LOT of think white smoke and a strong gas smell - I might have flooded it with all the starting attempts, though.

I pulled a spark plug and it's very black, and oily (picture of the spark plug included).

I took an oil sample, you can see new oil in the shot glass on the left, and my dark-looking oil on the right.

Anyone have any advice on:
1) what could be the cause/problem of this?
2) how to proceed? How to i fix it?

Thanks so much to you all in advance!

Road surface Automotive tire Wood Rectangle Asphalt

Liquid Drinkware Water Fluid Tin can

Household hardware Finger Thumb Auto part Gas

· Registered
2 Posts
Discussion Starter · #6 ·
First of all, thanks to all of you for the many and interesting replies! You're great0

I'll answer your questions as best i can:

  • as far as I know, the egnine was never rebuilt
  • the odometer says 25.000 miles, seller said 125.000 miles. No knowing how many times it really rolled around, though.
  • the carb was changed about 1.5 years ago from the original autolite 2100 to a holley 500 cfm street avenger
  • I had driven the car quite recenttly, most recently was a week before the issue. 3-hour drive and it drove like a charm
  • the oil is abouit a year old. I've driven about 1000 miles since the oil change.
  • i don't think the oil smells like gasoline, but i'm terrible at smelling things so not 100 sire :)

I'm pulling the rest of the spark plugs today to see how they all look individually. New ones have been ordered and are in the mail. I've also got a new set of spark plug wires sitring around, so I will take this opportunity to switch them out as well.

Once the plugs/wires have been replaced, I'm gonna try to start it, just to see what happens.

Basically next actions:
  • pull/inspect all plugs
  • put in new plugs
  • put in new wires
  • check float level (there's a little glass window on the side of the holley carb
  • If all the spark plugs look equally black/oily, was thinking about making the mixture a bot leaner too

After this i'll try to start her up, see what happens.

I'll post back here with the results, any further advice is greatly appreciated - keep it simple i'm a bit of a hobbyist/noob ;)
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