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carburetor
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Supporting Member of Barthmobile.com 4/11
Picture of Tommy B. Willis
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Trying to answer bill h's questions.

quote:
Is it hard to start cold when it has sat for weeks? Probably. See next question

Is it hard to start cold when it has sat for a day? Yes, it is hard to start every day, or two days or after a week.

Does the accelerator pump work well? When the accelerator is depressed gas squirts down in the primaries

Does pumping the throttle half a dozen times
before cranking make any difference? No, you have to pump it 30 or 40 times. I know this is not correct. If you do this with the top of air cleaner off it will backfire a little. Ir scared the h___ out of me when this happened

Does the choke do its thing? Is it free? The rivets on the choke housing can be drilled out and replaced with screws for adjustment to compensate for the aging of the bimetallic coil inside. Not sure about choke, yet.
Once it lights off, does it run OK? When it cranks it will stumble for 20-30 seconds, may take a little longer, and then it runs great.

Is there fuel in the bowl after it has sat? This can be checked by looking down the throat as the throttle is pumped. When the throttle is pumped I can see gas being squirted in the primary side of the carb.

Q jets like to leak when really hot from a soft plug on the underside. This can cause hard starting, as the engine must be cranked to fill the float bowl. It seems to be filling the bowl??, but it also acts like the timing is off, or the choke is not working.
This is also a potential fire hazard. Check for fuel residue under the carb. The area should be cleaned well and a couple of paper towels packed under the carb. After a hot run, any carb leak will show up when the paper towels are inspected. Or a good sniff and visual test after a hot shutdown is good, too.
I will do the paper towel test tomorrow. During this cranking ritual i do not recall seeing the secondaries ever open,



A single conversation with a wise man is better than ten years of study.

"When injustice becomes law, resistance becomes a duty."

8408-3125-28FP3
1985 28' Regal
454 Chevrolet
P32 Chassis
 
Posts: 67 | Location: Central Mississippi  | Member Since: 05-26-2006Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 6/12
Formally known as "Humbojb"
Picture of Jim and Tere
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Tommy, Classic Industries in Ca probably can sell you the original fuel line that connects the fuel pump to the carb. No rubber hoses needed. I bought one for my 85 Regal. 800-854-1280 or www.classicindustries.com


Jim and TereJim and Tere

1985 Regal
29' Chevy 454 P32
8411 3172 29FP3B
Gear Vendor 6 Speed Tranny
 
Posts: 3174 | Location: madisonville tn usa | Member Since: 02-19-2005Reply With QuoteReport This Post
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Supporting Member of Barthmobile.com 11/13
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OK, we've eliminated the bowl going dry and we know the accelerator pump is working. The fact that you have to pump it 30 or 40 times could point to a choke problem. The fact that it stumbles after light off could also point to the choke.

However, clogging of small passages in the carb can act like a choke problem. The choke is supposed to give you a richer mixture when it is starting and cold. But if things are clogged inside, there still could be a problem with fuel getting where it's supposed to be.

I would not suspect timing unless you have reason to think something moved the distributor. Certainly, the backfire could indicate a timing problem, but a lean mixture would also do that. Does it backfire any other time? A malfunctioning choke would give you a lean mixture with a cold engine.

Of course, checking the timing is always good, as is a good visual inspection of the inside of the distributor. Make sure there is no dust of the red death (wasn't that a Poe story?) inside, and the advance weights are free and lightly lubed.

It is possible that a weak spark can cause starting problems. This could be anything from old plugs, weak coil, bad wires, rotor, cap, etc. Sadly, very few shops have Allen scopes any more. However, a weak spark will usually show up climbing hills, etc, as well. But a good hot spark assures better starting, so it is good to check.

So, as far as self help, looking at the carb, you need to clean it inside and out. Inside is well served by a dose of Red Line cleaner. Outside by one of the spray choke cleaners. The choke should go closed when the gas pedal is depressed and let up. It should stay closed for a little while, then slowly open up as the engine warms up. The metal tube from the choke housing to the manifold hot zone needs to be clear, too.

You will not see the secondaries open unless there is a lot of air flow at higher engine speeds.

Always wear eye protection when a carb intake is open. I have an old marine spark arrestor I stick on for backfire safety.


.

84 30T PeeThirty-Something, 502 powered
 
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Also, when checking timing, the distributor's weights get seized or rusted inside and this will affect the centrifugal advance.



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Posts: 7289 | Location: Newburgh, New York | Member Since: 05-10-2003Reply With QuoteReport This Post
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Info for anyone following my breakdown saga:

SHE RUNS we finally got her started today but she needs a little fine tuning.

Thanks to all that offered help and hope Smiler for a while we were not sure of the outcome.


Mary

Don't mess with us old folks, we don't get old by being stupid!
1968 Barth trailer, 1975 Barth Motorhome and 1985 Barth Motorhome

 
Posts: 1623 | Location: Obion, TN/Memphis, TN | Member Since: 11-23-2004Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 4/11
Picture of Tommy B. Willis
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Automatic choke was the cause of my hard starting problem. Apparently, the screws that hold the thermostat in the carb had vibrated out and it fell out . I found thermostat and screws laying on top of the intake. Re-installed the thermostat and it fired and ran at the first turn on the starter. Thanks for the help and advice. Now I have a generator that wants to flood the bowl of the carb??



A single conversation with a wise man is better than ten years of study.

"When injustice becomes law, resistance becomes a duty."

8408-3125-28FP3
1985 28' Regal
454 Chevrolet
P32 Chassis
 
Posts: 67 | Location: Central Mississippi  | Member Since: 05-26-2006Reply With QuoteReport This Post
First Month Member
Supporting Member of Barthmobile.com 11/13
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quote:
Originally posted by Tommy/MS:
I have a generator that wants to flood the bowl of the carb??


Two likely causes are:

1. Something holding the needle off the seat.

2. The float is no longer floating.

Number 1 is more common. A good dose of Red Line fuel system cleaner is an easy thing to try before going any farther. It is a superb carb cleaner-outer, and might clean out whatever is in your needle and seat. Another thing to try would be some compressed air into the fuel inlet to dislodge whatever.

Carbs that sit a lot develop strange stuff in the float bowl, so it is never a bad idea to have a look inside, anyway.

A new fuel filter would be a good idea.


.

84 30T PeeThirty-Something, 502 powered
 
Posts: 7397 | Location: AZ Central Highlands | Member Since: 01-09-2001Reply With QuoteReport This Post
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I will give all of those suggestions a try.
Thanks



A single conversation with a wise man is better than ten years of study.

"When injustice becomes law, resistance becomes a duty."

8408-3125-28FP3
1985 28' Regal
454 Chevrolet
P32 Chassis
 
Posts: 67 | Location: Central Mississippi  | Member Since: 05-26-2006Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 2/16
Captain Doom
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NAPA Vacuum switch listing, Possibly this is the one


Rusty


MilSpec AMG 6.5L TD 230HP; built-to-order by Peninsular Engines:  Hi-pop injectors, gear-driven camshaft, non-waste-gated, high-output turbo, 18:1 pistons.  Fuel economy increased by 15-20%, power, WOW!"StaRV II"

'94 28' Breakaway: MilSpec AMG 6.5L TD 230HP

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