So we're doing a 73 restoration project

[jayhawk]

Michaelwk, I don't know if you have seen this youtube video about repair and tune up of 240Z flat top carbs, but if not, maybe this will be useful.  (don't know personally, as we have not yet started work on the flat tops for my '73): 

 

[Captain Obvious]

Pretty good video. Some mistakes on some details and some wrong names for stuff, but nothing harmful. He pulled one of the float pins out with tweezers at about twenty minutes in. That's how the float pins are "supposed" to come out. Hopefully yours will be that easy.

My biggest issue is that he spent a whole lot of time dinking around with dry mechanical float measurements... Tang should be some precise distance from the bottom of the float chamber? Rulers and calipers and all that? That's not the important part. What really matters is that the fuel depth is at the correct level in the sight glass. That's why they put in a sight glass in the first place!!  Put the float tang wherever it needs to be to get the wet measurement where it belongs. That dry measurement is ballpark only.

Get it close dry mechanically. Finalize it wet off the car by pouring gas into the carb. And then confirm final setting in place on the car.

He says he was never able to get a view of the bowl level with the carbs on the car? Well, you better be able to figure out a way to do that because at the end of the day, that's the only measurement that matters. All the rest of that dinking around to get things spot on dry is preliminary setting only.

Another issue with the whole video is it seemed staged and based on false premise. At the beginning, he's trying unsuccessfully trying to start the car with the air cleaner off. Well no shite.... The car won't start with the air cleaner off. That's probably because he's created some massive vacuum leaks with the air cleaner off. And then at the end, it still won't start because there's a wire off the ignition? Well who's to say that wire wasn't off at the beginning as well?    

The false premise...

My car won't start.
I "rebuild" my carbs (without even replacing the float needle valve or bowl gasket or disassembling the power valve to put in new diaphragms).
Now my car starts and everything is all better.
As proof, here's some shots of me happily tooling around my neighborhood.

Don't get me wrong, I'm not really knocking it. I'm happy to see someone actually working on the flat tops and giving them some love. That video could have just as easily been "here's how you take them off and replace them with round tops".  Haha!!

[Dave WM]

best birthday present I ever got, "bolt buster" induction heater. Expensive as heck but worth it after the hassle of a couple of hard to get at bolts get sheared off.

Now I see China is getting in on the action

https://www.banggood.com/900W-Rusty-Nut-Screw-Remover-Ductor-Magnetic-Induction-Heater-Kit-Automotive-Flameless-Heat-p-1336959.html?gmcCountry=US&currency=USD&createTmp=1&utm_source=googleshopping&utm_medium=cpc_elc&utm_content=frank&utm_campaign=pla-mix-us-pc-0626&gclid=Cj0KCQjwsMDeBRDMARIsAKrOP7F54ipCMtEAcUhjlNt-tpYl87Zh4oP721bngv-yv0LVuAnF7Gz2h3IaAvhdEALw_wcB&ID=48035&cur_warehouse=CN

Edited October 24, 2018 by Dave WM

[Michaelwk]

@jayhawk  Thanks for that link!  I actually think I watched part of that video a couple years ago, but I'd forgotten all about it until you posted it.  Definitely had some good details, like using the tweezers for the float pin, and was nice to see someone working on the exact same carb I have.  The grease on finger trick was also something I never would have thought of, but will definitely help getting some of those nuts back on. 

Based on how much fuel came out of his one carb, I think I'm on the right track.  Both my carbs had very little fuel in them when I opened the bowl.

@Captain Obvious  Thanks for the additional advice!  I ordered a couple rebuild kits so I can replace the gaskets, valve, etc.  No point in having to take the carbs apart again for that in the near future (assuming I get it dialed in decently after this first attempt).  I plan to clean up the outside also, especially that window, so hopefully I won't have too much trouble seeing the fuel level.  I have a mirror I use on my bicycle helmet which works beautifully since it's on an adjustable stick.  Also, my secret trick is wearing a head lamp when I work.  Always puts light right where I need it. 

I also didn't know that the car wouldn't start without the air cleaner on... good to know!

Hopefully the rebuild kits arrive by Saturday and I can do this all over the coming weekend. 

 

Michael

[Michaelwk]

11 hours ago, Dave WM said:

best birthday present I ever got, "bolt buster" induction heater. Expensive as heck but worth it after the hassle of a couple of hard to get at bolts get sheared off.

Now I see China is getting in on the action

https://www.banggood.com/900W-Rusty-Nut-Screw-Remover-Ductor-Magnetic-Induction-Heater-Kit-Automotive-Flameless-Heat-p-1336959.html?gmcCountry=US&currency=USD&createTmp=1&utm_source=googleshopping&utm_medium=cpc_elc&utm_content=frank&utm_campaign=pla-mix-us-pc-0626&gclid=Cj0KCQjwsMDeBRDMARIsAKrOP7F54ipCMtEAcUhjlNt-tpYl87Zh4oP721bngv-yv0LVuAnF7Gz2h3IaAvhdEALw_wcB&ID=48035&cur_warehouse=CN

Interesting tool... that might have to be a christmas present to myself!

 

[Captain Obvious]

Well it's not a guarantee that the car won't start without the air cleaner. However, there are some hose connections (like the thermostatic inlet air valve and the idle compensator) that will present as vacuum leaks if they are not connected to the air cleaner (or otherwise plugged).

So if you're running way rich, then having those tubes bleeding air directly into the intake manifolds would actually HELP the engine run. But if everything is tuned properly and you are not running way rich, those unmetered air sources would make steady idle impossible and would probably prevent engine starting.

Viewing the float bowl levels is easy with one of those little one inch diameter mirrors (on a telescoping stalk) in one hand and a bright flashlight in the other. Once you figure out how to angle everything, you can check the bowl levels on the car in a matter of seconds. Might be able to do it with a head mounted lamp as well, but I've never tried that.

[jayhawk]

16 hours ago, Captain Obvious said:

Viewing the float bowl levels is easy with one of those little one inch diameter mirrors (on a telescoping stalk) in one hand and a bright flashlight in the other. Once you figure out how to angle everything, you can check the bowl levels on the car in a matter of seconds. Might be able to do it with a head mounted lamp as well, but I've never tried that.

I wonder if one of the cheap endoscopes on Amazon (some less than $20) that attach to a smartphone would work for checking the float bowl levels:

 

[Captain Obvious]

Unless the endoscope has a ninety degree head on it, you might not be able to fit it between the two carbs to view the rear sight glass. Would work easy for the front, but might not work for the rear. A little mirror on the end though, could convert to a ninety degree view.

Tell ya what... Come to my place and I'll show you how to see the bowl levels in situ!

$3.99 at Horror Fright. This and a good flashlight:

[jayhawk]

On 10/25/2018 at 6:32 PM, Captain Obvious said:

Unless the endoscope has a ninety degree head on it, you might not be able to fit it between the two carbs to view the rear sight glass. Would work easy for the front, but might not work for the rear. A little mirror on the end though, could convert to a ninety degree view.

Good point.  I looked on Amazon and some do come with a mirror, or you can purchase a mirror for these endoscopes separately.  https://www.amazon.com/Magnet-Mirror-Borescope-Wireless-Endoscope/dp/B074M8QGBF?keywords=endoscope+mirror&qid=1540604733&sr=8-4&ref=sr_1_4.

I'll get one and see how well it works in a couple of weeks when I visit my car at Motorman7's.  I'll report back here.

[Captain Obvious]

Neat. Those mirror attachments look like they might be just the ticket for getting down between the two carbs. Do report back. That would be easier (albeit more expensive) than what I do. And once you have a tool like that, I'm sure you can come up with other uses!

[siteunseen]

I want one!  As my eyesight gets a little fuzzier everyday. ?

[darom]

I have one of those $3.99 Harbor Freight mirror tools (what is left of it). Just be careful extending it too far - I was inspecting one of my 04 Ford's powerstroke's cylinder heads (valve cover removed, injectors and high pressure oil rail out) when the telescopic tube got disconnected and I dropped 2 metal little flat plates down my engine. I found one. The other ended up in my IPR valve blowing a hole through its metal screen. These plates are used in the H&F tool to hold telescopic pieces together.