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Author Topic: Carb trouble  (Read 14021 times)
RazorbackNOR
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« on: February 13, 2008, 07:36:16 pm »

The Murena seems to have a bit of trouble with the carb. Needs a lot of choke to start, and when the choke is cut of, it spits and fires a couple of times, before dying out.

Any ideas what it might be...?
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2010 Mazda 3 1,6  Diesel Gunmetal Blue
1983 Matra Murena 2.2 Platine
50cc Pocketbike
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Anders Dinsen
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« Reply #1 on: February 13, 2008, 09:37:49 pm »

Most likely a vacuum leak, I'd say.
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'82 Murena 2.2 prep 142
'01 Grand Espace 24v
'08 Smart Fortwo 0,8 cdi
Oetker
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« Reply #2 on: February 14, 2008, 09:06:11 am »

Quote
-------
Most likely a vacuum leak, I'd say.
-------------------------------------------
Think so to.
Look at the hose in the lefside front where the plastic rubber connection is for the headlamps.
if it dies out the fuelpump can be a problem to.
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I feel like Jonah, only my fish looks different.
Murena 2.2 Red 1982. Murena 1.6 black on places.
RazorbackNOR
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« Reply #3 on: February 14, 2008, 01:07:46 pm »

Fuelpump IS a problem......

It is leaking, but PO has bought a new one that is on its way from Simon as we speak.
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2010 Mazda 3 1,6  Diesel Gunmetal Blue
1983 Matra Murena 2.2 Platine
50cc Pocketbike
IPSC shooter
RazorbackNOR
Sr. Member
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Posts: 494



« Reply #4 on: March 03, 2008, 09:24:42 am »

Hmm. been looking at the closest vacuum hose from distributor to carb, seem just fine, no cracks, no leaks. but seems like there are som other vacuum hoses going round down there, does anybody know which hoses go where?

And would a bad gasket on the carb give me the same kind of trouble....?
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2010 Mazda 3 1,6  Diesel Gunmetal Blue
1983 Matra Murena 2.2 Platine
50cc Pocketbike
IPSC shooter
Oetker
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« Reply #5 on: March 03, 2008, 10:10:42 am »

I give my best shot, aldo I am not a carb specialist.
If I had to find out I should do it like this.

First check if vacume on the ignition works.
Open the ignition.
Get the hose from the carb that goes to the vacume on the ignition.
Suck on it and see if the plate moves in the ignition and runs free.
Some oil may help there if not.
Adjust ignition without vacumehose on ignitiojn to 10 degree before udp cilinder 1.

disconect the vacumehose that goes to the plastic vacumepot and shut it of on the carb.
Try if thing go better.
If a gasket is bad between carb and inlet manifold, fix that first.
« Last Edit: March 03, 2008, 10:15:23 am by Oetker » Logged

I feel like Jonah, only my fish looks different.
Murena 2.2 Red 1982. Murena 1.6 black on places.
RazorbackNOR
Sr. Member
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Posts: 494



« Reply #6 on: March 03, 2008, 10:18:15 am »

Hard to tell from here, but could probably be in better shape, considering takeing it of and checking.....
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2010 Mazda 3 1,6  Diesel Gunmetal Blue
1983 Matra Murena 2.2 Platine
50cc Pocketbike
IPSC shooter
Oetker
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« Reply #7 on: March 03, 2008, 10:24:11 am »

A trick.

Take some vacumehose and put one side in youre ear.
Start the engine and listen with the other end around the gasket.
If you hear somewhere a changed sizling sound you can find out.
Do the thing I told you above first to eliminate things.
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I feel like Jonah, only my fish looks different.
Murena 2.2 Red 1982. Murena 1.6 black on places.
Oetker
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« Reply #8 on: March 03, 2008, 10:27:18 am »

Another thing, get of the airbox and check it.
Might have some loose foam in it wich can disturb things.
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I feel like Jonah, only my fish looks different.
Murena 2.2 Red 1982. Murena 1.6 black on places.
Anders Dinsen
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« Reply #9 on: March 03, 2008, 11:33:14 am »

There's a few things that can go wrong.

As the car needs choke to run, it seems to be running too lean, but it could also be poor ignition. Don't touch the distributor yet as the car should be able to run without the vacuum advance working (it's an economy device).

Check for vacuum leaks first. You have inspected the vacuum to the distrubutor, that's good. There are two hoses connected to the manifold: Ensure that there are no leaks there. One goes to the brake servo, the other to the popup headlight mechanism. Inspect and replace any worn hoses.

Check ignition (not the distributor yet): Check all spark plugs. Check the leads with an ohm-meter (should show between 1kOhm and 3kOhm AFAIR depending on length). Check the distributor cap and rotor. The cap should be without signs of sparks on the terminals, and the same goes for the rotor. Replace both if you are in doubth.

Then remove the carburettor, take it apart and clean it. This car has been standing for a long time, right? Petrol can form a greasy substance over years which will block the small passages in the carb. Take a look at my page http://dinsen.net/murena/carburettor/ for inspiration. Replace main gasket and o-ring, and needle valve. Adjust float height. Your photo just shows the connections to the carb, it shows nothign about how it looks inside!

You have a new fuel pump, but the pump is probably the least critical component in this system. The carb must be perfect, though.

I owe all I know about this to Roy - we can ask him if you run out of luck, but I think you have a bit to work on now Smiley

Good luck!
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'82 Murena 2.2 prep 142
'01 Grand Espace 24v
'08 Smart Fortwo 0,8 cdi
RazorbackNOR
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« Reply #10 on: March 03, 2008, 11:48:19 am »

yes, i know..... was actually a pic i took of the fuel inlet, just posted it cause it was around there. Seem to remember someone talked about how to check if there where any leaks on the carb-head gasket.... could a leak here give these problems? The tank and vacuum to the tank seem ok, since the lights rise normally.
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2010 Mazda 3 1,6  Diesel Gunmetal Blue
1983 Matra Murena 2.2 Platine
50cc Pocketbike
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Anders Dinsen
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« Reply #11 on: March 03, 2008, 02:47:37 pm »

yes, i know..... was actually a pic i took of the fuel inlet, just posted it cause it was around there. Seem to remember someone talked about how to check if there where any leaks on the carb-head gasket.... could a leak here give these problems? The tank and vacuum to the tank seem ok, since the lights rise normally.

Leaks in the circuit for the popup headlights show when you shut off the engine and switch on the light: even several minutes later it should be able to lift the headlights (at least once).

Yes, the gasket can cause problems, but not likely. More likely is a restricted or blocked fuel channel.

I have had the gasket leaking slightly, but that did not cause any running problems, only petrol fumes in the engine room (smell of fuel).

You need to address this problem very systematically or you will end up frustrated and have wasted a lot of time! Wink
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'82 Murena 2.2 prep 142
'01 Grand Espace 24v
'08 Smart Fortwo 0,8 cdi
Oetker
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« Reply #12 on: March 03, 2008, 02:52:22 pm »

quote Anders
----------------
 Don't touch the distributor yet.
------------------------------------------
Sorry Anders, I don't agree on that.
If the rubber inside the vacumepot on the ignition is leaking, then false air will come from there in the carbs right away.
If the car was standing for a very long time you should also change the fuell, and agreed, the carb should be cleaned.
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I feel like Jonah, only my fish looks different.
Murena 2.2 Red 1982. Murena 1.6 black on places.
Oetker
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Posts: 1048



« Reply #13 on: March 03, 2008, 03:00:23 pm »

or in case you are lazy, put in a new carb Grin

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I feel like Jonah, only my fish looks different.
Murena 2.2 Red 1982. Murena 1.6 black on places.
RazorbackNOR
Sr. Member
****
Posts: 494



« Reply #14 on: March 03, 2008, 03:08:32 pm »

I guess a bottle of carb-cleaner would be a TOO easy way to go then.....  Cheesy Grin
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2010 Mazda 3 1,6  Diesel Gunmetal Blue
1983 Matra Murena 2.2 Platine
50cc Pocketbike
IPSC shooter
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