Reading Spark Plugs

[leotismumford]

Hello everyone this is my first post and any assistance would be greatly appreciated. I have a 1985 C10 Scottsdale Stepside with a 350 engine, Holley 4bbl, turbo 350 trans. Truck will not even spin a tire. Cranks and idles well, no smoke, no knocks, trans shifts well. Revs slow and not much torque. Just seems under powered. for a cruiser it runs great. I put a K&N air filter to have plenty of air flow and new plugs. Been a while since I've looked at spark plugs so I'm including the pics on this post hoping that there are still some out there versed in the black arts of plug reading and that they may share their wisdom.

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[Snoots]

Change those plugs. You have an HEI ignition so gap the new plugs at .045. Check your timing. It appears that your timing is retarded. I believe your initial timing should be 10-12 BTDC. Make sure your vacuum advance canister on your distributor has manifold vacuum and is operating properly.

 

[fast 99]

I've seen far worse. Might be a little rich or burning some oil but nothing I would get overly concerned about. Don't forget the mechanical advance.

 

[leotismumford]

Thanks! I'll round up the timing light. Once I drive it about 20-30 minutes it doesn't want to start as easy as when it is cold. a few times it has run backwards (or that's what the older guys called it) when I shut it off after driving it a while. I do have an HEI and the plugs are set at .035. Also running a small holley 4bbl I'll get the model number but it looks to be a small one like a 650cfm. Factory heads with a mild cam as quoted by the seller.

 

[SquareRoot]

Thanks! I'll round up the timing light. Once I drive it about 20-30 minutes it doesn't want to start as easy as when it is cold. a few times it has run backwards (or that's what the older guys called it) when I shut it off after driving it a while. I do have an HEI and the plugs are set at .035. Also running a small holley 4bbl I'll get the model number but it looks to be a small one like a 650cfm. Factory heads with a mild cam as quoted by the seller.

Probably got a decent amount of carbon buildup. That can create "hot spots" in the cylinder and cause pre-ignition especially after its warmed up. "Back in the day" it we would pull the air cleaner, rev it up to about 3500 and dump ATF in it. Smoked like hell but it actually cleaned the carbon out. Had the side benefit of killing the mosquitoes for a 1/2 mile radius. I would put in a new set of plugs just cuz.

 

[fast 99]

High idle may cause run-on. That can be very destructive to internals.

Hard hot start has been a problem since the invention of carbs. A few things that can be tested or tried:
high fuel pressure
high fuel level in carb bowls
add a phenolic spacer
use non ethanol fuel
higher octane fuel

Others here may add additional possible solutions.

 

[Snoots]

If it runs backwards when you shut it off, it's a timing issue.

 

[potent rodent]

like stated before check your timing, check your vac adv its either on ported or full manifold vacume

 

[Craig Nedrow]

Dieseling or running on is normally caused by advanced timing for the gas you are using.