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Old 4 Weeks Ago   #46
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Re: Jesus, would someone help?

Hi Grubeguy

Sounds good on the timing front. i can normally see the fuel going down inside the carb, i cant remember where it comes out of though. i do recollect seeing the vapour fumes in the inlet when the engine is hot but stationary and not running.

Tim
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Old 4 Weeks Ago   #47
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Re: Jesus, would someone help?

^^^ The fuel from the accelerator pump comes out of the acc. pump nozzle which looks like a little tapered alloy bar c. 3mm wide or maybe like a little beak projecting into the space between the inner and outer parts of the auxiliary venture i.e. close to the edge of the carb intake tract. This 'pump nozzle has a tapered hole underneath, slightly angled in order to direct the spray of fuel towards the centre of the carb bore. In practice the spray should ideally take the form of a tapered cone, you may find in practice, it's just a line of fuel being ejected.

If the top cover is removed from the carb, you should be able to see this acc. pump jet/nozzle clearly to one side of the auxiliary venturi. It wil be either pressed into a hole in the gasket surface or be held in place with a brass screw. There will be a delivery valve (ball and spring?) either bulit-in or just under it.
There are also a system of 1 or more ball valves into the accelerator pump unit and it's passageways to act as intake and discharge valves. Any of these ball valves can stick due to sediment build-up etc and can stop the accelerator pump from working. There is also a rubber type diaphragm inside the acc. pump housing which can become torn/perforated or the piston/plunger attached to the diaphragm can stick. Sometimes the carb will need to be soaked in solvent/carb cleaner to free things up, some people prefer to clean passageways using an ultrasonic cleaner.

Any workshop manual should show the above components/fuel circuits to allow you to trace them and check they're all clear.

Al.
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Old 3 Weeks Ago   #48
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Re: Jesus, would someone help?

A quick update - I've since been reminded to put the timing light pickup on #4 cylinder's wire, which when the engine is started, puts timing back to the 10-20 degree range. Looks like timing has been half the issue.

I'm still awaiting the manifold (and plunger) that I ordered, so I've not taken the carb off yet.

So an interesting tidbit - the car will start now without starting fluid but I still can't get it to idle reliably under 2000 rpm. Also when I first start it, it'll rev up to what seems normal for the thing, but then die, as if it's gas starved. This'll happen two or three times before the idle settles in and the car remains running.

Also, even when warmed up, the engine loves full choke. When I push the choke all the way in, the car won't run whatsoever. I have the idle mixture screw at 1.5 turns out from seated.

I'm also using a glass fuel filter, which is absolutely clear of junk, and when the engine was rebuilt, I had the tank boiled out and re-sealed. Does this sound like I have junk in the carb?
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Last edited by Grubeguy; 3 Weeks Ago at 13:07.
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Old 3 Weeks Ago   #49
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Re: Jesus, would someone help?

Hi Grubeguy

Yes your car WILL feel like its gas starved, this is due to the extra air going in where the plunger is not yet fitted.

Full choke adds more fuel to the mix, in other words allowing for the extra air.

Sit tight and wait for the plunger

Tim
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Old 3 Weeks Ago   #50
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Re: Jesus, would someone help?

Hi Grubeguy

If you look at the posting about "seat 850 leads"" order and use the sections 1 2 3a and 3b this should get the timing on the correct cylinder.

remember cylinder 1 is the one at the pulley end and nearest to you when you are working on the car( it say cylinder numbers in the casting on the head by the spark plug holes).

I dont think you have junk in the carb, you just have no plunger

Tim
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Old 2 Weeks Ago   #51
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Re: Jesus, would someone help?

Well, the issue wasn't just the plunger. I'll start from the top with a timeline.

The replacement manifold came and it spent a day in a carb cleaner back. So did the plunger, which also needed polishing with 1200 grit sand paper. I installed the thing after plugging up all (I mean ALL) the holes, reinstalled the carb, and it made no difference. I still needed starting fluid to get the thing going, it still idled like hell, and it wouldn't run without choke.

My buddy and I pulled the carb and took the top off, where I discovered I had verdigris/oxidation more than halfway up the float. I removed that with a vinegar soak and checked the float level - the damned thing needed to be adjusted in both positions. Both measurements were WAY off.


I pulled off the idle and main jets to discover both were plugged at the tip (I previously checked this and looked only at the holes halfway up the jet), as was the throttle accelerator pump nozzle. I pulled all three from a spare/junk carb I have, verified nothing plugged, and put them on the "best" carb.

"Best," by the way, denotes the one where the bushings were replaced by Pierce Manifolds.

We pulled the rest of the carb apart, looking for other signs of oxidation, cleaned everything anyway, reassembled and reinstalled the carb. I also emptied the tank using my electric pump and replaced the gas with a jerry can of fresh stuff. After letting the gasket sealant dry for 24 hours, the car started like a charm and now idles at 1500 or so without complaint.


I'm at a loss for words on the oxidized and improperly set float ...

See details at


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Old 2 Weeks Ago   #52
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Re: Jesus, would someone help?

Hi Grubeguy

Great news then, well done. 3 different carbs working badly. bet your relieved

A new tight engine will need a slightly higher than normal idle for a little while.

there should be a small drain nut in the bottom of the fuel tank if you wish to drain/flush again

Good progress

Tim
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Old 2 Weeks Ago   #53
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Re: Jesus, would someone help?

Hi Grubeguy,

I watched your video.

A few observations:-

1) Cleaning out the idle jets - the idle jet that you showed can be separated into 2 parts, they just pull apart, the join is at the base of the threads. You can use 2 pairs of pliers to separate the 2 parts of this jet (use some jaw protection, if you're ham-fisted). The 2 holes in the side are what allow fuel from the emulsion tube to enter the idle jet, the tiny hole in the end is what meters the fuel (according to the number on the jet e.g. 45 = 0.45mm orifice) into the idle hole in the carb bore adjacent to the throttle plate when it's at idle. So the tiny hole is the one that's important, not unusual for a little bit of dirt to remain inside the idle jet despite soaking/blowing out, unless it's separated into it's 2 parts for cleaning.

(This separation/cleaning of the idle jet was covered recently in the Fiat 126 section, if you're interested check out the thread 'Non Starter! HELP PLEASE' see posts#10,12,15.)

2) It looks to me that your choke flap is not closing fully (from what I can see in your video). It needs to completely close off the opening for cold starting.
Also it appears that the interconnecting link from the choke and the throttle isn't actually opening the throttle when the choke is engaged (on). This link rod adjustment by judicious bending was covered earlier in this thread by 'timmycm850'. Iirc, with full choke engaged, the throttle should be opened by this linkage to give an idle speed of c. 1500 rpm.

3) Looking at your video where you show the carb top removed and are discussing the float adjustment - did you remove the large brass nut (c. 19mm or maybe larger?) adjacent to the fuel pipe intake and return connections.
Under this brass nut, there is a nylon mesh filter, this often gets choked with sediment etc. Cleaning this gauze filter is regarded as part of a normal full service on the car and should have been done on a re-built carb.

Good to see that you finally got your engine running. Just goes to show that you can't always trust the work of others, including professional 'shops!

Al.
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Old 2 Weeks Ago   #54
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Re: Jesus, would someone help?

Al,

NO KIDDING (re: trusting a shop's work). Hard lesson learned indeed. At least I learned how "not to" by doing - I can;t learn a thing unless I actually do it.

The 19mm nut - no, I didn't remove or inspect, though I suppose I should have.

Regarding the choke flap, keep in mind that I didn't engage the choke when I started the car in the video. Adjustment is gently bending of the linkage, yes?

Now that the little bugger is running, I might as well fill up the forum with other requests and such
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Old 2 Weeks Ago   #55
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Re: Jesus, would someone help?

Quote Originally Posted by Grubeguy View Post
Al,

NO KIDDING (re: trusting a shop's work). Hard lesson learned indeed. At least I learned how "not to" by doing - I can;t learn a thing unless I actually do it.

The 19mm nut - no, I didn't remove or inspect, though I suppose I should have.

Regarding the choke flap, keep in mind that I didn't engage the choke when I started the car in the video. Adjustment is gently bending of the linkage, yes?

Now that the little bugger is running, I might as well fill up the forum with other requests and such
Hi Grubeguy,

Sometimes mistakes are made in 'shops e.g. one person might have cleaned the outside of the carb, intending to strip it later. Another person might have seen the 'cleaned' carb, assumed it was finished and sent it back to the customer? The amount of corrosion/green build-up on the float is unusual - I wonder if some sort of chemical soak was used on this carb and not cleaned off?

The mesh filter under the 19mm nut beside the fuel pipes on the carb is accessible without removing the carb top (you're probably fed-up doing this).
Just put a rag underneath as a small amount of fuel will escape when the nut is undone. The mesh filter usually stays in the hole and just pulls out - a small mirror is your friend here in seeing what you're doing. Just clean and refit the filter followed by the 19mm nut -iirc this nut doesn't use any type of sealing washer, it has a taper seat instead.

As you're running the engine with an idle speed of 1500 rpm at the moment, there's no point in messing with the choke linkage connecting rod to the throttle unless you later cut the idle speed down to c.900rpm and want to be able to start the engine in cold conditions. (I note that this doesn't apply to where you are at present, although I did hear mention of the choke and did iirc see it being engaged early on in your video when you were trying but failing to get the engine to start).

You might compare this link rod on your other carbs to get an idea of the 'normal shape' - it looks to be to have been straightened a little, there's usually a gentle but noticeable slight bend in one location, maybe 1/3 of the way along? (relying on 40 year old memories here ).

As you're running with an idle speed of 1500? rpm at present, bear in mind that the engine is probably drawing fuel from the progression holes in the carb bore and maybe not from the idle fuel hole. As a result you might find that adjusting the idle mixture screw has little or no effect, I'd recommend setting this mixture adjustment screw to 1, 1/2 turns out from a lightly seated position and leave it alone. (just for clarity - the idle mixture screw is the one that screws into the carb body near it's base, the idle speed screw is the one that is fitted on the throttle linkage and it's end bears against the carb body).

Hth,

Al.
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Old 2 Weeks Ago   #56
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Re: Jesus, would someone help?

Al, I'm with you - I'm 1.5 full turns out on the idle mixture screw, and am using the idle adjust as needed. I can take it down to about 1000rpm, but the engine barely runs. Honestly, now that I have a working, starting and idling engine, I'm just about tickled pink. I know there's always work to get done and improvements to be made, but having walked away from the car for a couple years (not counting starting the engine once a month or so), my interest is reinvigorated. I might even make it a daily driver until the heat and humidity becomes unbearable ...
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