Surely your car is exacting revenge due to being separated from it's Kugelfischer!

You know the remedy!

;-)

Cheers,

Ray

Mr-2002tii wrote:

Guys I 've had it with the drafts, its powerful and all, and I do want to keep them but there's always something, so here is my problem, when I step suddenly on the gas from a complete stop, it bogs for a second and then it takes off maybe its because I only have screens in front of them and not air filters and it gets a lot of air, I don't know what the problem could be- I tried to show off today with a spinning start and it bogged down on its face. Help!!!! Main jet 140 55F8 Rebuilt E21-1,8 motor with mild head work.

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'73 ///M2 2.5
'84 ///M635CSi

this is from my book "how to build and power tune Weber and Dellorto"


just highlighted this yesterday.

"A too small accelerator pump jet will cause the engine to die momentarily when the accelerator is depressed. Too large an accelerator pump jet causes the engine to 'bog', which effectively amounts to the same thing, (a slow car) and then pick up after the excess mixture has been removed from the engine"

"the following gives gives a basic starting range of accelerator pump jet sizes for modified engines (Ie with long duration camshafts, worked cylinder heads, high compression, extractor exhaust systems). Try the smallest jets first. The accelerator pump jets are listed as average, so expect to come down for sized for engines that are not overly modified."

Weber range for average use is 30, 35, 40, 45, 50, 55, and 60

500cc per cylinders (m10 ballpark): 45 on the high side, and 40's on the low side


that might head you in the right direction.

it gets more complicated with needles and stuff, but that's the basic guideline
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needy and demanding 72 02

Check to make sure the little rubber o-rings are in good shape for each accelerator pump. They're the big ones in plain sight on each barrel. Operate the throttle by hand, and see if any fuel leaks around them. If they can't hold any pressure, the the accelerator pumps will shoot fuel out thru the o-ring instead of sending it to the engine.
Just a thought, as its something easy to check.

But really, your fuel level might not be right. Do a search or contact dapbmw on setting the float level properly. You have to do it by actually checking the level of the fuel in the carb, with a main jet removed, using a measuring stick in the top while the engine is idling. I can't remember the exact number. 40mm comes to mind, but thats just a guess and I could be way off.
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4224479: 74 2002, #74 EP/FSP, daily driver
I beat my car like it owes me money!

It's a E21 motor guy!!!!

ray_koke wrote:

Surely your car is exacting revenge due to being separated from it's Kugelfischer! You know the remedy! ;-) Cheers, Ray Mr-2002tii wrote: Guys I 've had it with the drafts, its powerful and all, and I do want to keep them but there's always something, so here is my problem, when I step suddenly on the gas from a complete stop, it bogs for a second and then it takes off maybe its because I only have screens in front of them and not air filters and it gets a lot of air, I don't know what the problem could be- I tried to show off today with a spinning start and it bogged down on its face. Help!!!! Main jet 140 55F8 Rebuilt E21-1,8 motor with mild head work.

What size chokes are you running? If you want you 1.8 to have some low end grunt you should be in the 32 to 34mm range, also a 140 main jet is on the rich-end for a 1.8l engine to be running. Give us a list of your.

choke size

air corrector

emulsion tube

pump jet

when set up right the DCOE's should run with little fuss.
_________________
Marty
Don't worry about the world ending today,
Hell it's already tomorrow in Australia.

just getting ready to get started on carb install...this ought to be helpful

you did not post all of your jet and choke specs.

before you blame the carbs, is your timing right on? valves adjusted right? properly? distributor, ignition and fuel pump working ok?

make sure your floats and needle valves are in good condition. if not replace them. there might be also some dirt on the internal passges or the jets themselves?

to set your floats right the wet method is better. drive the car for a bit then park in a level spot and turn off the engine. remove the jet inspection cover and remove one of the main jet holders with the emulsion tube and jets. use a 1.5 or 2" finishing nail and slowly lower it to the hole till the nail hits the fuel/gas .now measure from the base on the top of the carb to where the fuel hits the nail. make a notch on the top of the nail or paint it so you get an accurate reading.

it should be 25mm +/-1mm. if not within that range adjust it.

for accelerator pump jet 40 or 45 is ideal and for the needle valves 200 or 225 is ok.

now there is also a simple fix for the bogging, try plugging the fuel bowl valves shut, this sometimes remedies the problem.

Oh, just give up, take 'em off,
put them in a box and send them to me!

heh.

t
_________________
I have a car disease. There is no cure.
I'm not even managing the symptoms very well...

I would gladly send them off, but problem is I donated the fuel injection to a fellow E30 enthousiast, and the sound they make is heavenly!!!

Mr-2002tii wrote:

It's a E21 motor guy!!!!

still, a tii needs the k-fish system- it's a matter of executing your custodial duties. i assume you 're not responsible for the wrong motor in the car; hopefully you do have some of the pieces, the proper block if nothing else. cut your losses now, and find the correct style k-fish system for your build number.

you'll thank me in the end.

robert w.

what year tii do you have? which of the tii bits do you still have left? anyway try to set your timing to a little bit advance it should reduce or eliminate the bog down.