RUNNING ON

[123abc]

just put in my freshly built clevo has a decent cam some port work small chamber heads relieved comps about 10/1, holley 570 street avenger 68f 72r jets 6.5 p/valve and im using 98 in it, my prob is im getting run on when i shut it off if i retard the timing it idles shit advance it it runs on any ideas and not running hot

[hybrid]

Check float height, and potentially lower your idle a little if you can.

[unilec5544]

What ignition system are you running?

[123abc]

electronic i had the same setup on my old motor worked fine i only reused my carb but the cam is quite a bit larger 223/224 duration and 507 lift im thinking maybe pv and jets are too small im only getting about 5 vac on my holley vac guage if i ramp up timing i get pinging under accel but maybe its too lean

[unilec5544]

Some electronic systems can cause run on by retaining a small current build up, also you can have this issue with plugs that are in the wrong heat range, so what plugs do you have?

[123abc]

number 6 in heat range ngk

[Shaunp]

idle too high?/ bit lean maybe.

[123abc]

it was suggested that my pv is to small 6.5 as im only getting about 5" of vacum at idle it may be fueling up

[hybrid]

Fueling up shouldn't cause run-on, but happy to be proven wrong.
It's usually a timing/lean/idle speed issue.
It's essentially pre-ignition, so the causes are often the same and being rich is generally not one of the causes.

[123abc]

changed the pv and reset the carb while off the idle slot was open to far but i cracked the back ones a little and closed the front ones up seemed to work but still dies off after idling for a while the more it idles the worse it gets like running out of fuel blip the gas and it springs back into life, drives fine to just wont hold an idle for long,

[123abc]

seem to have the run on sorted but idle new issuei wonder if the pump is to light for the job

[unilec5544]

Wow 5in. vacuum, doesn't seem a lot, you must be running a big cam or you have a vacuum leak somewhere. Try spraying some carb cleaner around the carb and manifold.

[Shaunp]

Wow 5in. vacuum, doesn't seem a lot, you must be running a big cam or you have a vacuum leak somewhere. Try spraying some carb cleaner around the carb and manifold.

Nah 224 @50 and 500 thou, not a super big cam.

[123abc]

checked for leaks doesn't seem to be any vac issues unless it coming form the bottom of the valley gasket ill try to upload a video tomorrow

[123abc]

gapped plugs at 35 tested for vac leaks played with tyiming a bit