Is this 73 CS is it running right?

J

Jendon2

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Here is a question for veteran cs owners .. being a newbie
Im not sure how a stock cs should feel or run? It seems kid of sluggish on taking off..like there is sort of a miss or stumble before it gets going ..seems to idle fine around 10,000 just when I push the accelerator it seems to sort of drag or take its time before it gets going not very smooth? just feels kind of heavy or lugging.is this the way a stock older cs is? Just put in new petronix elec ignition, have not replaced plugs or wires yet? Any ideas, I feel it runs great when its reved through the gears but kind of slow and heavy until you really punch it.. maybe this is normal your thoughts and knowledge here would be great

Don Smith
 
How long since the carbs were synched ?

it's been over 25 years since i drove my 2800 cs, but I remember
similar symptoms when the carbs were not optimally synched
over the full rev range, rather at a specific rpm.

I don't know how many times I had those carbs apart.

mike
 
Don,

question, how old is the gas? my recommendation (if you don't know) is to drain the tank, replace the fuel filter. start with the basic things. put new plugs, wires.

cheers
scott
 
I haven't driven mine when it was running properly yet, but sure remember a few rides in a new one back in the day. They pull very smoothly and rev out nicely. About twenty years ago I had a worn out Bavaria that had a very strong engine. It was a blast to run through the gears and built speed very linearly. I think you need some tuning.
 
Check your timing and carb accelerator pumps. There are threads here explaining how to adjust if they are not squirting down the carb when the linkage is moved off idle when accelerating, hesitation will occcur if no squirt.
 
Hesitation off the line--

+1 re carb accelerator pumps--assuming you have the original Zenith carbs on your E-9--

The pump injectors must squirt a fine spray of fuel at initial movement of the throttle or the lag/hesitation you describe will persist. The injector(s)--one in each carb--are prone to gum up and must be clean for the car to get off the line smartly.

Cleaning requires their removal--be very careful not to drop them as they are brass and can fall down the throat of your carb(s)--bad happening!!

Be sure to note their orientation aiming down the throat of each carb as that will affect their proper functioning. A very fine strand of wire along with a soak in solvent should clear the small orifice. Also as suggested--be sure the fuel you are using is clean, free of contamination and fresh.

Do these steps first as the condition you describe is usually directly related to your description of sluggish acceleration off the line problem. HTH
 
Don,
In my years of working on older BMW's whenever I have had to diagnose poor performance , especially off idle accleration, and the first thing I always check is the entire ignition system working correctly. By entire I mean the mechanical and vacumn advance units and well as whatever triggering system being used and what is the voltage to the coil. Does the OT mark on the flywheel line up with TDC on the cam or OT on the front pulley if you can see it. I always use the flywheel for timing. You would be suprised by how many people overlook the advance systems. They need to work correctly for the car to accelerate. If you have a two way vac unit does it work both ways. Because of emissions all the US coupes had two way units. My 70 2800 has the small dist but still has a two way vac unit. One way to test the unit is with a handheld vacum pump, you need to see if the diaphram is still good. The port closest to the dist is retard the other one is advance An alternative test is to connect one vacum port at a time to manifold vacum with the engine running. Retard the engine slows down and advance it speeds up. Set base timing with the advance/retard unit disconnected, I would use 22degrees@200 rpm less than stock ( more advance) as a starting point. When set the retard side is connected to manifold vacum and the advance is connected to ported vacum. The engine will slow down as it should and pickup with no hesitation with a snap throttle opening. You may have to adjust idle speed but it should not be a large adjustment if everything else is working ok. The mechanical advance is tested by turning the dist rotor clockwise and releasing. You should feel spring tension when you turn the rotor.
Once you have all of the ignition system working correctly then you can move on to fuel. Many places to go there but check for vacum leaks first. The Zenith , in fact I prefer them over the Weber, the early version is a great carb but can be screwed up very easily. You should have the later emission version which if they have not been screwed with will work but not as well as the earlier ones.

A bit of wisdom I learned years ago from a racing engine builder. You need to strike the match at the right time for everyhing to work the way it should.

BT Fields
 
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