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1275 With Weber 45 Issues

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#1 Brucey

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Posted 23 April 2018 - 04:10 AM

Hi, 

 

I have a 1960 Austin Mini with a 93 Rover 1275 in it. I am running electronic ignition with a brand new 12V unballasted coil. I restored this car recently so most of the parts including the Weber 45 DCOE are brand new. I am using NGK BP6ES plugs. I have listed the specs for the carb below:

 

Chokes 34mm

Main jet 150
Air corrector 180
Emulsion tube F2
Pump jet 40
Idle 50F2
Aux vent 4.5
 
Mr. Gasket 42S micro fuel pump 2-3.5 psi

 

My issue is as follows. The car does not start, and on the few occasions that it has it ran with a very rough idle and died within 10 seconds. If I went anywhere near the throttle it would die immediately. On occasion after the engine died, a cloud of thick white smoke would puff out of the velocity stacks. It smelled of fuel, so I imagine this is vapor fuel?

 

I have verified that there is fuel getting to the carb and that there is a spark at the leads. I cannot get a timing light on the engine as the car does not run, but my timing is estimated to be roughly 10 degrees. I have inspected the plugs and they smell of fuel and are starting to get a bit black. My idle mixture screws are set to 2 turns out after being screwed all the way down.

 

This sounds like a fueling issue and I have attached a picture of what my float bowl looks like. The carb is mounted at an angle due to the inlet manifold, and therefore the float bowls are filled unevenly. Could this be an issue, if so how would I go about fixing it?

 

Any help would be much appreciated!

Attached Files


Edited by Brucey, 23 April 2018 - 04:11 AM.


#2 Dusky

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Posted 23 April 2018 - 05:46 AM

Is it a standard engine?
Can you verify the pump jets are working?
Try starting it with the jet inspection cover removed

#3 nicklouse

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Posted 23 April 2018 - 07:40 AM

I would be starting by setting the timing.

 

you say you think it is at 10 deg. but it might be at 20 deg. so I would work on getting that sorted. a bulb across the coil used to be a good start.

 

re the float chamber it is just one.

 

you have fitted the rubber carb to inlet seals and set the crush washers or rubbers to the correct settings?

 

personally I would swap out the weber for an HIF44, it will make the same power and give better fuel returns.



#4 Retroman

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Posted 23 April 2018 - 11:08 AM

The angle of the carb should not e an issue

 

I would make setting the timing accurately a priority then try again

 

Its usual to find when starting a Weber carbed engine that there is a knack.

 

By that I mean its usually one or 2 pumps on the gas pedal before turning the key and then maybe just very light throttle to hold a high tickover, then maybe a few blips and if its warmed enough it should tick over on its own...have you set the idle screw too?

 

Don't keep pumping the gas pedal as it is literally squirting fuel in.

 

This will wet the plugs and possibly cause what you are up against, plus the timing.

 

I have sometimes had to heat plugs up to burn the fuel off and the heat can help the starting of a new unit too.



#5 Brucey

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Posted 23 April 2018 - 02:53 PM

Firstly, thank you for all the replies. 

 

Yes, the engine is a stock 1275 unit. I am using Misab plates and Thackeray washers between the carb and the inlet manifold to prevent vacuum leaks.

I did pump the throttle twice prior to starting. I have not yet adjusted the idle screw, I will do that to increase the idle speed I assume?

 

Timing does sound like an issue.Could someone please elaborate more on the test bulb method or any other method to set this?



#6 Rorf

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Posted 23 April 2018 - 08:17 PM

Sounds like it is totally flooded.

 

Are you getting spark?



#7 timmy850

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Posted 23 April 2018 - 10:49 PM

You can also get a helper to turn the car over while you slowly sweep the distributor through the range. I assume you've got the plug leads and distributor all around the right way. When you have the engine turned over by hand to 10 degrees the rotor should be pointing toward number 1 cylinder on the distributor cap

 

 

http://new.minimania...8A56D83229B.jpg
0E88EB0A-01FA-5CCC-53E5D8A56D83229B.jpg
Link: http://new.minimania...plug_wire_order



#8 Brucey

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Posted 07 June 2018 - 05:43 PM

Hi guys, 

Sorry for not updating but here it is. The car is now running, but I have been having an issue of an absurdly high idle (5k rpm). I have tried dropping down an idle jet size and searching for air leaks but no luck. I have even taped around the misab plates to ensure a good seal, but that doesn't fix it.

 

It is not a stuck throttle either, because I took a video looking down the barrel of the carbs to ensure that the throttle is not sticking open, and it's not. It has to be a large airleak somewhere for such a high idle, but I have no clue where it might be. I'm afraid to use carb cleaner to locate it, because that will only drive the rpm higher and it's already at the redline......

I do have a bad rocker cover gasket, could that be an issue?

Here is a link to the video:https://youtu.be/wKdYjpRmeMM

  



#9 Allrounder

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Posted 07 June 2018 - 07:24 PM

Can’t tell from the video but do you have the rubber seals between the carb and inlet manifold??

#10 Brucey

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Posted 07 June 2018 - 08:01 PM

Yes, I have the misab plates with thackeray washers installed. I don't have paper gaskets either side of the o-rings though, and I read somewhere that those are a good idea. Maybe that could be part of the issue. I've got some on the way, along with a new exhaust manifold gasket.



#11 nicklouse

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Posted 07 June 2018 - 08:21 PM

no paper gaskets. just the Misab plates and correctly tensioned tackery washers.



#12 Dusky

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Posted 07 June 2018 - 09:58 PM

Spray with water. That drops the revs. Were all o rings on the progression port hole banking screws installed? Does it lower the revs when screwing in the mixture screws? If not id suspect the choke barrels.

#13 Brucey

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Posted 08 June 2018 - 12:32 AM

I will check the progression holes. Could you elaborate on the choke barrels? I did change the chokes when I was re-jetting the carb, so maybe I did something wrong during the installation?



#14 Dusky

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Posted 08 June 2018 - 09:13 AM

Sorry, i meant the cold start piston, wrongly translated it :)
https://classiccarbs...9/64330.003.jpg

#15 Brucey

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Posted 09 June 2018 - 02:39 AM

Found the issue, idle speed screw was in just enough to be a problem. Didn't realise it would have such a large effect. With it closed the car will not run, as it does not get enough fuel but with the idle screw dialed in it would run at high rpm. The fuel bowl is draining faster than it is filling even with adjusted floats, so I've got a larger needle and seat on the way to increase the flow rate into the bowl.







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