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MG Midget and Sprite Technical - New Air cleaner: No instructions

I bought a "Longflow" air cleaner for my ZS carb. It has a small plastic elbow that could attach to the back plate of the air cleaner assembly, but it came with no diagram so I have no idea what to do with this.

Is it a vacuum line? Does it go to the charcoal canister?

Planning to start the new engine sometime in the next few days, and hoping to have everything hooked up right.

Thanks.

--john
jf Falconer

Hello John,

I checked my '77 midget 1500 with the single ZS carb. There are no elbow fittings and lines coming off the stock air cleaner assembly. All of the lines - fuel, vacuum, charcoal canister, and choke - are plumbed directly to the carb. My car was orginally purchased in California and these cars do have some differences with Federal spec cars.

I've seen a couple of 1500s with aftermarket air cleaners at car shows. Neither of them had lines coming off their air cleaners. IIRC, it seemed most, if not all, of their other lines were present.

FWIW, my '72 (with a single Weber carb/air cleaner) does have an elbow fitting with a line running to the oil separator on the timing cover.

Perhaps your fitting is an optional piece for different applications...?

Gryf has a 1500; maybe he'll weigh in here shortly.

Good luck with your engine start!

Cheers,

Glen
G. D. Phillips

My '76 has stock Federal emissions and there isn't anything coming off of the air filter housing either. Everything comes off the carb/intake manifold.
Clive Reddin 76 Midget

Thanks, guys. Seems like it has mutiple applications, and in my case the fittings aren't needed.

As expected, my effort to start the new engine didn't quite go as hoped. Once I narrow down the issue I'm sure I'll be asking for help!

(all I know so far is that there is no fuel coming out of the pump.)

Thanks.

--jf
john

JF: You haven't by any chance reversed the fuel lines on the pump have you? I've done that. Twice in fact!

If they are on correctly and no fuel flow, you may have a torn diaphragm in the pump.

If that's still ok, blow some air down the fuel line and listen for bubbles in the tank. There is also a small rubber type of fuel line under the chassis near the back of the engine. Had that break on me too!

All of those will stop you dead in the water.
Clive Reddin 76 Midget

Clive--

Thanks for the tips. You have broken thru my despair. I have a ZS carb, and there are two nipples. I put the charcoal canister vacuum line on the top one, and the fuel on the bottom. Hope that is right.

I've been worried about a line getting plugged during the "unassembled" phase that lasted a year. Your air bubble method sounds like a good way to test that. Am I right that there is no fuel pickup in the tank? Just the pump on the block, I think.

I'm also assuming that an air leak anywhere in the line will make it hard for the pump to suck the fuel, so I'm going to try to check that.

Feels like another "vacation day for midget work" coming on.

--jf
jf Falconer

Hi!

Right, the stock 1500 had no vacuum lines coming off the air filter box.

As for the vacuum pickoffs on the carb, the large diameter one draws through the charcoal canisters and from the vent on the rocker cover. The smaller connection is the vent from the float chamber. On my '78 it points forward, and is plumbed directly into the front charcoal canister down by the radiator. I think that on the earlier ones, it faced rearwards and went to the single canister up over the RH footwell.

-:G:-
Gryf Ketcherside

JF, the fuel inlet line on the Z-S is on the bottom of the carb.

There's a fuel pickup tube in the tank and only the fuel pump pulls fuel through the line. Any air leak may render your fuel system inoperative, depends on how big the leak is. No air leaks obviously is best!

The other thing and I haven't done it is that you didn't put the curved part of the fuel pump behind the camshaft did you when refitiing the pump? It is supposed to push against the camshaft and as the cam turns, it activates the pump.

That will stop fuel flow as well.

To see if you have fuel flow is to disconnect the fuel line at the carb and put the hose into a container and crank away!

Myself though, I'm leaning toward something simple such as no fuel, pump mounted incorrectly, fuel lines reversed on pump, plugged fuel line, broken rubber line under the body near transmission, ruptured diaphragm in fuel pump.

All are easily corrected though thank goodness!
Clive Reddin 76 Midget

Clive--

Uhh.... You may have hit on the issue. I recall working hard to get the arm of the fuel pump to hook under the cam (this was about 3 months ago). Sounds like a good place for me to start my investigation. I hope it is this simple.

As mentioned above, the tank and much of the line sat idle for a year, but I'm hoping nothing really changed. The pump was working when I took it out, so I wouldn't think the diaphragm is damaged.

Assuming there are no surprises at home tonight, I'll try blowing bubbles in the tank and then pull the pump and see what we can learn from there.

Thanks much for the clues. I'll report back.

--john
jf Falconer

Another way to verify fuel flow is to fit a clear filter just upstream of the carb. If you see fuel in the filter, it should be reaching the carb okay.

By the way, the fuel inlet for the ZS carb isn't exactly on the "bottom" as stated by Clive. It's on the back face of the carb, pointing toward the firewall, near the choke assembly.

-:G:-
Gryf Ketcherside

But do NOT expect to see the filter fill up. My mind still has issues with seeing a vertical fuel filter with the lower third filled, nothing ever seeming to go above that, but the car running just fine.
David "mysteries of science" Lieb
David Lieb

This thread was discussed between 21/03/2008 and 25/03/2008

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