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21' Daytona
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395 Posts
Discussion Starter #1
Not on a boat, but on my `67 Fairlane Hardtop. Factory 390 4V Holley. I can't seem to get the surging out of it. If I set the timing where it runs good, it pings and surges. If I back the timing off, it's lazy and comes to an idle slowly, and just plain ol idles/runs like crap (along with drinking the fuel...more than to be expected). I can't remember the number of the carb off hand, but it's a factory `67 4V application. The engine has a mild cam and true 2.5" exhaust, nothing special. I've checked for vacuum leaks and have the correct PV's in it.

Looking for a little insight on something I may be missing ??? Thanks guys !!!
 

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steelcomp was here
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26,512 Posts
Not on a boat, but on my `67 Fairlane Hardtop. Factory 390 4V Holley. I can't seem to get the surging out of it. If I set the timing where it runs good, it pings and surges. If I back the timing off, it's lazy and comes to an idle slowly, and just plain ol idles/runs like crap (along with drinking the fuel...more than to be expected). I can't remember the number of the carb off hand, but it's a factory `67 4V application. The engine has a mild cam and true 2.5" exhaust, nothing special. I've checked for vacuum leaks and have the correct PV's in it.

Looking for a little insight on something I may be missing ??? Thanks guys !!!
Check the vac advance diaphragm. Are you disconnecting this when you set your timing? Also, check for a worn out distributor. Worn points plate, worn shaft, just plain worn out.
 

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21' Daytona
Joined
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395 Posts
Discussion Starter #4
I am disconnecting the dist vacuum when setting base timing, and have sucked on the vacuum line while engine is running...rpm's increased. I have not pulled the distributor out to see what shape it's in. A good idea, maybe send it out to have the curve checked as well.
 

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Registered
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2,234 Posts
Something jumped out at me when I read this, has it ever run well?, sounds like it jumped time (cam), what is the vacuum at idle?, maybe plugged exhaust also, would explain the pinging...

Sometimes the answer is so simple you look right over it...
 

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Cantard
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5,017 Posts
Something jumped out at me when I read this, has it ever run well?, sounds like it jumped time (cam), what is the vacuum at idle?, maybe plugged exhaust also, would explain the pinging...

Sometimes the answer is so simple you look right over it...
Good point. What are you setting the base at? Vac would /could also tell a story. What are your points gaped at?
 
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