Ironracer
Gearhead
Heck Yeah! That a great Thing!
Idle drop by 500 rpm?
- Thread starter Ironracer
- Start date
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Ironracer
Gearhead
The damn thing was fine after I fired it up yesterday, thumping..... it spit at me again, today after I came home from work... That Engine Has NEVER done that.... ever! Maybe I should try blocking the brake master line off...
512Stroker
We are all here because we are not all there.
If you mean "spit at me" that is back firing out the carb, that is more related to a timing issue, or an extreme lean condition.
Are you using a stock harmonic balancer?
Timing will not have a 1200rpm difference from part to drive.
You have a major vacuum leak.
Opening the idle screw and moving the idle mixture screws out to compensate for a lean condition caused by a vacuum leak.
You have a major vacuum leak.
Opening the idle screw and moving the idle mixture screws out to compensate for a lean condition caused by a vacuum leak.
Ironracer
Gearhead
Yessir, stock Balancer
Ironracer
Gearhead
When she popped outta the Primaries yesterday, even though the Carb has alleged " blowout protection " could that pop a power valve, And would that cause a vacuum leak?
No. you can take the PV out and throw it in the ditch and it will not affect idle. POWER valve. It's on the POWER circuit. Not the idle circuit.
I tried to point out that it sounded like a vacuum leak and advised you to inspect for such many posts ago. I'm backin out of this, because now you're going in so many directions, I'm not sure you'll ever get it right.
Either too lean or not enough timing. Kim
I was trying to tell him how to eliminate the timing as a suspect, and I'll be a mutha ****** if somebody doesn't come in and send him off a different direction. It's not about being right. It's about helping the guy out of process of elimination and these guys just jump on and just **** up a good diagnostic flow chart. So I give up.
Always good to have a spare good working carb around to put on and see how nice it runs.
Edelbrock 1406 600 cfm, electric choke. Done Deal
You think not enough timing could cause a 1200rpm drop from park to drive?
I don't think so, but maybe.
Yes Process of Elimination, best way to get to the bottom of the problem.
A blown power valve will cause an extremely rich condition and the idle mixture screws will have no effect if it is blown.
I tend to agree, but until it's eliminated as a suspect, I'll be sumbitch if we'll ever know. It's called diagnosis. You eliminate one system at a time. I've been doing diagnostic work on carbureted and distributed engines for over 40 years. There's a procedure. I tried my damndest to outline it. **** it.
Could be both. He had the carb off so the base gasket could be bitched. Kim
No it won't. Tell me how. The throttle blades are closed at idle. There MUST be airflow across the boosters to pull fuel from the power circuit. The rich idle from a blown power valve is a myth that's been repeated over and over again until it's been believed and it's dead wrong.
Ironracer
Gearhead
Well, I'm just spitballing RustyRatRod, it started Blasting Rain and lightning, plus it was dinner time. So I was simply asking if that would do that. My Bad, Dude. All my Lil Non Rubber caps are there. Cause the Rubber ones dry rot In a year or so. The carb base and intake were wiped w/ a Lil Alcohol yesterday, plus it sounded and ran killer, at first. When it backfired through the carb, could it have split a cap? Other than pulling the 3/8 line to the brake master, I'm not sure where to look... any suggestions? Could the backfire have blown the intake gasket? If I knew, I wouldn't be bothering Ya! The only actions I've taken a Wrench to, is ones You kindly gave me. My Bro Doug has a 770 on his 460, he said he'd bring it by at one point. The ol lady, him , and I will be outside, cutting bad stucco, replacing a door jamb, painting, and doing a metal roof over a mobile home this week, so I doubt I'll get to do but a Lil at a time... sucks Bro. If You care to give me a list, to work down, Id Greatly appreciate It Rob! Close the secondaries first? Then Do the timing w/ a vacuum gauge? I'd like to rule out a vacuum leak... hell, I don't know where the heck to start, i just wanna get there! Thank You Rob!
Ironracer
Gearhead
Bought a new composite Mr Gasket 54c yesterday..
It's ok. It's not you. I'm trying to give you a diagnostic map and you're gettin railroaded around every corner. I realize now I just caint do it from here.
Ironracer
Gearhead
Aww Man...
Good of you to help out @RustyRatRod
Hopefully some of the guys looking in learned some of the diagnostic steps on how to go about this.
Over the internet diagnostics, no easy task.
Ironracer
Gearhead
Agreed George Jets! @RustyRatRod, That Brother has Helped me Alot, alot of Y'all Have, weather Ya know it or not! I was on FBBO when I built the 66 Sat. Propwash and Kim both helped me. Was along time ago. And the recipe for the 340 was pulled outta here, back then. From me Lurking! EVERYONES Help is GREATLY appreciated, DAG-NABBIT! ( Best Denver Pyle Voice-over )
512Stroker
We are all here because we are not all there.
Easy big Boy, easy.
The OP is never going to get the engine to idle at 450 rpm in drive regardless of what you or anyone else recommends.
Keep up the good work and remember your blood pressure.
Stay Kool
Jim K
I'm not trying for 450.
512Stroker
We are all here because we are not all there.
There is a good possibility that the balancer has slipped on the rubber isolation ring and is no longer giving you an accurate timing indication, pretty common with older stock balancers. It would be a good practice to verify that the timming marks are correct.
First follow the trouble shooting guideline's that members like @RustyRatRod have recommended
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