Just bought a 1973 240Z, won't start

[Weasel73240Z]

I just bought a 1973 240Z with 26,000 original miles on it, from the original owner. The car is in amazing shape, very little rust, but has not run much over the last several years. The girl I bought it from said she started it every few months, but it hadn't started for about 8 - 9 months. Its been garaged in Massachusetts since it was new.

I'm new to the Z (I've wanted one my whole life, and finallly found "the one"), and I definitely don't know much about these Hitachis flat top carbs. The car will run if I spray starter fluid in the carbs. I'm getting fuel to the carbs (I cranked it with both lines disconnected), and it runs with starter fluid, so I'm sure there's spark. What should I do first, just a real thorough carb cleaning to make sure there's no build-up inside.

And if that's the answer, does anyone know where I can get an exploded view of this type of carb. I don't like working on carbs "blind". Nothing worse than seeing a spring fall out, and not knowing where it came from.

[e_racer1999]

welcome! and yes, it sounds like your carbies are all gunked up. i don't know of a website that has an exploded view of flattops; i know that there are a few people on this site that have had success in rebuilding those carbs, though. perhaps they will chime in....

[DaveN]

Exploded view... go to carfiche.com The microfiche section has the S30 series parts fiches. Section 10B covers the 73' flat tops.

This site is primarily for British SU owners, but has good "how they work" and how to maintain material, much of it applicable to all SU versions.

http://www.teglerizer.com/sucarbs/index.html

[JimmyZ]

Congrats on the new Z!

I think you're right in assuming it's gunked up carbs. Mine sat on a shelf for years and the needle valves were seized with some white residue. Laquer thinner works great as a dissolver/cleaner of varnish. Also check that the exit end of the fuel rail is flowing fuel. There is a pin sized hole which helps maintain pressure. Don't enlarge the hole if clogged but instead run some LT through it and blow with air.

It's pretty straightforward taking the float bowl covers off. Remove fuel line and screws holding float cover on then tap a little to break the gasket if any. Just be gentle with the float and it's arm. A pair of needle nose will easily remove the float hinge pin. From there soak the top of the bowl in a glass of LT and it will free up. There is a very fine spring/wire retention doohickey on the end of the needle. (At least on my round top SU's) Soaking is a better approach if the needle is seized due to the possible damage to this part if you slip while gripping/pulling. Keep the LT away from the float if it's plastic. I wouldn't want to find out if it could stand up to LT.

2c

Jim

[JimmyZ]

Disregard my post above. Just took a look at the Haynes manual and found that the flattops are VERY different from the roundies.

http://images.google.com/imgres?imgurl=http://www.ztherapy.com/images/Flattops.jpg&imgrefurl=http://www.ztherapy.com/technical_stuff/spotterguides/zcar/240spotter.htm&h=135&w=210&sz=5&hl=en&start=5&um=1&tbnid=Y_ErE3LGhZC8tM:&tbnh=68&tbnw=106&prev=/images%3Fq%3D240z%2Bflat%2Btops%26svnum%3D10%26um%3D1%26hl%3Den%26safe%3Doff%26rls%3DGGLD,GGLD:2004-21,GGLD:en%26sa%3DN

Here's a link to Ztherapy with a fuzzy picture of what they refer to as a "boat anchor":)

The Haynes M did have some nice pictures and maintenance descriptions for the flattops though.

The flat tops are nowhere near as simple as the earlier style SU's.

[sblake01]

Here's a link to Ztherapy with a fuzzy picture of what they refer to as a "boat anchor"

And from the Ztherapy link:

Evil things, these square mouthed carbs. If you have these carbs on your 240Z-trash them and get ZTherapy SU's

As I have said before, flattops not as good as rountops but can be usable, but this company has always been over zealous in their bad mouthing of flattops. I'm sure that that's in part that they don't sell or rebuild flattops which opens up the market for the 6/72-11/74 cars. I don't work with flattops anymore since I have EFI cars now but back in the late 70s into the 80s a friend and I used to rebuild them and they worked fine. If I could do it (with help-he had the shop) then it can be done. End of story, just my opinion, not trying to open up that debate again. Clean them up and see how they work before you think about roundtops.

[geezer]

Welcome to the site. Are you kidding me? 26,000 original miles? I don't think I could bring myself to change a thing on this car if it's in this good of a condition. I think it would be worth your while to learn all you can about these dreaded flat tops. Others have got then to run well without problems. The fear of the unknown & the lack of money to be made servicing them have forced many to swap them out, maybe prematurely, taking the easy way out. Just depends how concerned you are with originality and do you have the mindset & patients to learn about and maintain these carbs?

[MikeW]

Are you sure the fuel itself is good? You probably don't want to use fuel that's been sitting in the tank for 9+ months.

[geezer]

You should check the internal filters and clean them if they are clogged. Both types, F1/R1 & F2/R2 have an internal filter.

[Weasel73240Z]

Thanks to everyone for the help. I took the round tops apart today (I just couldn't wait any longer) and I think i found my problem. The needle valve on the front carb was stuck, so the fuel bowl couldn't fill. The bowl was dry as a bone. Cleaned it up, freed it up, and I think I'm in business.

I was amazed at how simple the design was once I got the carb apart. I totally cleaned the damping piston housings, and got them to slide real easy. I haven't started the car yet, because I don't have any damping oil, and I spilled what was in there all over myself when I took it apart (lesson learned). I'll get some tomorrow and see if I found the problem, fingers crossed! How much of the damping oil should I put in to start? They are pretty much dry now.

Just to be safe, I'm replacing all of the fuel filters, cleaning all of the lines, and I tested both the mechanical and electric fuel pumps. They both seem to be working fine. I've got a feeling that I'll have her running by tomorrow night.

I'm think about removing the emmisssions stuff, but the car is so original, I'm afraid to remove anything. What do you think, to desmog, or not to desmog, that is the question.

I'll post some pictures of the car once I get a chance. It really is hard to believe that this car has been in Massachusetts for 34 years!

[sblake01]

......and I definitely don't know much about these Hitachis flat top carbs.........

.......I took the round tops apart today.......

Which do you have?

[EScanlon]

Weasel:

After you clarify which type of carb you have (Flat Tops are just that FLAT on top and the edge is definitely noticeable, while the Round tops have a domed top and a soft transition to the sides of the carb.) then you can take advantage of this site and really get all sorts of info.

As far as what type and how much oil to use, get 20 weight Motorcycle Fork damper fluid. Gary M. (Beandip) found it at a motorcycle shop and it has worked great for both of us. Some people will claim ATF or some other weight oil, but 20 wt is what the FSM calls for.

As far as how much, just enough to cover the top of the plunger that screws into the top of the carb.

By the way Beandip is the one that has (patiently)fexplained all this to me so if you have a bunch of questions ask him.

E