Weber 28/36 running too rich

[johnn1493]

Hi everyone
First post from me. I’ve a Series 2 with a stock 1470cc engine which is taking its first few runs after years off road. Over the last two years I have swapped the chassis and renewed most of the suspension etc. The engine received new liners from the previous owner and so I haven’t really touched that side other than changing fluids. All new fuel tank and lines and an electric fuel pump with regulator.
Starts reasonably well but black sooty exhaust. Plugs fouling up very quickly.
The 28/36 Weber looks relatively new. I’ve stripped and cleaned reset float height. Checked ignition timing, replaced plugs and coil.

All jet sizes are as per ford cortina 1500 settings in book.

Put all back but still running rich with sooty black smoke exhaust. Turning the idle adjustment screw seems not to make any difference.

Haven’t checked valve clearances yet or given it a compression test.

Any ideas would be gratefully received.
Thanks
John

[4129R]

Does the Weber have an air filter?

Dirty air filter will restrict oxygen and make the engine run richer.

If the mixture is rich, they start easier, but run too rich when hot.

[BDA]

  johnn1493!!

Wish I could help you with your carb.

I know we’d all love to see pictures of your baby!

[jbcollier]

“Electric fuel pump with a regulator”

High fuel pressures cause the fuel to “squirt” and create turbulence in the float bowl.  This messes with the jetting.  Fit a proper low-pressure fuel pump that does not require a regulator.

While waiting for the pump, check your valve clearances.

If you search the forum there are posts with recommended 28/36 jet settings.

[Clifton]

Without a wideband you won't know where it is rich.
https://www.youtube.com/watch?v=MMTC6u0Nmk4

[johnn1493]

Thanks for the responses guys.
 To answer the various issues. 4129R -Sadly the air filter is new, so no lack of breathing. BDA - I bet you say that to all the guys but I've not got the hang of uploading yet! JBC - Good point, not sure that it is a low pressure pump. I put regulator on to 'ensure' low pressure. The pump is a Facet Posiflow. Any suggestion as to a good replacement or should I go back to a mechanical pump?  Will try temporary gravity feeding fuel from a can to see if any difference. The valves will need checking though. Clifton - Wide band video link interesting.

BDA  in lieu of photos members may be familiar with the car as I rather foolishly bought it at auction, unseen, for far too much £££(after one too many glasses of wine). Bought from Mathewsons (see Youtube Mathewsons Lotus Europa April 2022). Mathewsons are a well known classic car auctioneer in UK (Bangers & Cash TV programme) and having auctions on a Friday night on-line, as they did then, was a masterstroke in marketing!! As stated, I discovered the car needed a new chassis so lesson well learned - Don't drink and bid!! :-)
John   

[4129R]

This one?

https://www.youtube.com/watch?v=C-WNDFGJkAs

[johnn1493]

Yes that’s the one.

[BDA]

BDA - I bet you say that to all the guys

Yep!

Johnn, the usual problem people have posting pictures is resizing. Here’s one way of doing that: https://www.lotuseuropa.org/LotusForum/index.php?topic=1379.0

Another way is here: https://www.youtube.com/watch?v=O_55eg00H-w Use the snipping tool to save a part or all of your picture and post that.

[jbcollier]

Facet Posiflow pumps can put out any where from 1.5 psi to 10 psi depending on the model.  The one you want would be the 60304 which puts out between 1 - 2 psi.  My personal favourite pump is a German-made, SU-l knock-off, pump sold by BPNW.

I do not recommend using a pressure regulator.  They have been known to turn into fuel “shower-heads” and, time and time again, I have found the marked scale to bear no relationship to reality.

[johnn1493]

Thanks JB I shall check which pump I have and change if necessary and shall remove regulator.
As to resizing photos thanks for the tips BDA. Hopefully I've attached a couple here successfully!
I shall inform of progress in eliminating black smoke.

[BDA]

Your pictures came through great, johnn!

[Dilkris]

“Electric fuel pump with a regulator”

High fuel pressures cause the fuel to “squirt” and create turbulence in the float bowl.  This messes with the jetting.  Fit a proper low-pressure fuel pump that does not require a regulator.

Hi John - I've just read this thread and stopped at your above comment. Do you have a recommended fuel pressure for Dellorto 45's - my new fuel pump is running at 3psi without a regulator in line. Would you consider this too high?   

[jbcollier]

3 psi should be fine.

[S2Zetec54]

 :Welcome:Car looks great…. Great wheels