Hi Folks,

I was able to take my new to me 914 for a short drive yesterday. The car is a 74 with what I think is the original 2.0. It has Dual weber 40's and what I think is the stock distributor. The cap and rotor look practically new and the plug wire in good condition. It wouldn't start a few weeks ago and I pulled the plugs (NGK 7) and cleaned them, fired right up after that (Never had webers before and I think I flooded the cycling a little pumping the gas pedal thinking it would help start.

Other observations.
The few times I have started it (usually after sitting over a week) I crank the engine, and give a dab of the gas pedal to get it to fire, usually takes several tries to get. running. After warming up a bit engine goes through revs well.

On the drive the engine runs very rough usually between 2-3k its barely pulling. Lots of hesitation and at odd times it pops to live a pulls great.

My first thought is to pull the carbs, do a thorough cleaning and check to see what jets are fitted and the condition of the floats.

Also planned are a timing check, valve adjust, oil and filter, fuel filter.

Is there any other details I can provide for suggestions on how to get things running well?

Thank you!
Steve

Welcome to carbs. You'll learn a lot.

You really need an AFR system to properly see what the engine is doing and tune accordingly. Could be lean mid-range, could be fat; could be the accel pump during transition. You just won't know w/o AFRs. - GA

EDIT: oh, and buy one of these: https://www.cbperformance.com/product-p/6537.htm

FWIW, usually the engine will catch after 3 slow regular pumps on the gas peddle when cold. Feather the gas for a minute until it idles on it’s own. As made 44s are pretty big for a 2.0. If that is what is installed. ESP if the webers have 36mm Venturi.

Those little tips on things like the start up help so much, It has 40's not 44's so I should be good there. Thank you!

Thank Greg,

Ideally I'd like to get it running well without adding much to the system, but I'll look at a AFR system.

I have a flow meter already that I've used for tuning Solex's on my 912 so I should be all set there.

I've seen folk recomend a book for tuning Webers (cant think of the exact book right now) but I'm not sure how helpful it would be compared to looking things up online and youtube videos. More research needed, and help from you guys!

You will find lots of carb info and jetting guidance here if you can spend some time doing searches, or people will pop them in eventually. Altitude matters...

SOT, where did you get the air hoses for the blower in that first pic?

I am also in the carb camp. What condition are the guts of the engine? compression, leak down, ... The carbs are probably tunable, but if the engine is not up to snuff, it is all moot.

They came with the car so not sure, they look perfect though, haven't seen anything exactly like them before.

If the car has been sitting for a while prior to your purchase I would definitely pull the carbs and go through them. Also make sure your fuel tank is clean and doesn't have junk plugging the outlet restricting fuel flow. I have refreshed a few cars after long period of sitting and fuel just gunks stuff up. They have ranged from a 356 that ran poorly to a 6 conversion that wouldn't even start it was so bad. Attending to the whole fuel system made them run great!

I dont think it sat without running for years, my understanding is that it was started and driven once in a while, Probably with some decent size gaps in there.

I looked in the tank and it looks very clean. I'll put in a new fuel filter in soon and before trying to run it again.

Agreed, maybe someone else will chime in.

Try some seafoam for a cleaner. I have some fogging oil for storage but I have not tried that for cleaning, not sure if that works, but you can spray in right in the carbs.

Skota23 I sent you a PM. Post a picture of your flow measuring tool. Fuel pump and location too.

While AFR gage is nice - carbs were successfully tuned without them for decades, and decades, and decades.

Webber 40s as purchased have venturi’s too large for good driveability. Putting a set of 40s right out of the box on the car results in over carburation for most 914s.

As produced 40s work pretty good on a 1971. It’s the 44s with the big Venturi that are dogs on smaller displacements. Back snapping and popping. Terrible transition. No telling what sort of cam is in the poster’s engine. A lot of unknowns. Starting with the fuel pump.

I have the 44s and yes on the back snapping, yes on the popping, but transition? Sorry can’t understand, (second lenguage issue here). My motor is 1974, 2.2L with ported and polished heads and manifolds. I use the car in high altitude Mexico City.
https://youtu.be/LIo7AnmsMPo

Click to view attachment
Click to view attachment

Try to determine which cylinder is missing at idle. Pull out the idle jet for that cylinder and blow it out. This is a very common issue with Webers as they run up thru mid throttle and RPM range on their idle jets. I carry a stubby screwdriver in my car the remove the idle jets at the side of the road.

Charlie

Basically 44s are too big. Especially so at high altitude where air has less density and requires less fuel.

You need to find Venturi’s that are about 28mm diameter to get a good vacuum signal. Rejet after you replace those. You’ll still have issues with off idle performance due to the larger 44mm throttle butterfly but it will drive better.

Ideally you should sell the 44s and use a set of 40s. In my experience running 40s on a 1911 cc engine with a performance cam, it needed smaller venturis 28s for good driveability. 30 mm Venturi’s were better on the top end at high RPM but that is not how a car gets driven in normal traffic.

@bbrock is at similar altitude - he posted his carb and jetting setup (for 40s) a while back.

Transition is how the motor performs as it comes off the idle jets (up to about 2500 RPm) and begins fueling off the main jets.

Most of the time at light throttle, the idle jets are providing the fuel.

Somewhere in this forum there's a chart from, I think, the Dellorto bible, but I can't find it now. Attached is bascially the same thing.

CB has 44 IDF venturis available down to 32mm:

https://www.cbperformance.com/product-p/6356.htm

A plugged or partly pugged idle jet will pop and low power and run poorly like a dead cylinder. When it hits the main circuit it will come alive again and pull good .

Webber 40 with 28 vents run pretty good with small stock engines( 2.0 and less) and stock exhausts

Thanks Folks, theres alot of good advise and places to start.

Some of you may be familiar with the car. It used to belong to Joan who was married to Dave from Triad West. I'll make sure to give a proper update on the car and some of the things that came with the car that will pay respect to Joan and Dave.

Here are a few more notes to clear up any confusion.

Its a 2.0 with Weber 40's
the 40's have 28 venturis installed

Car slightly hard to start (but its cold here in Wisconsin)
Idle is fine after warming up
Car runs poorly (*pretty much undrivable) when load is applied and mostly between 2-3k

More info to share with the group.

Location and type of fuel pump
Fuel pressure regulator
More photos of general setup

To do list
New fuel filter
Adjust valves
check timing
Pull carbs and clean (what are the odds it will need a rebuild kit?)

Theres probably more and I'll post things as I make progress and have questions.

Thanks again!

Clean the carbs well. Make sure the tiny holes (the transition holes) above the throttle plate are clear. The transition ports are doing the fuelling up to about 2500-3000 RPM. Set float levels (often overlooked) per Weber manual.

Just get the carb rebuild kits. Odds are very high o-rings, gaskets, diamphram for the accelerator pump, and the seal on the float needle have all seen better days. The kit is cheap relative to the time and labor to go though the carbs, and to resynch when all is reinstalled. Don’t be cheap. Do it right.

You’ll be back in business.

Thanks Superhawk996, good advise!

That is a clean 914.

The stock 2.0 distributor ?
I think you'll have to change that.
Those who replied with carb advise can probably offer dizzy info too.

I don't believe anyone has mentioned how important sync is. Not only sync between the barrels, but sync between left and right side.

After they have been thoroughly cleaned and rebuilt AND timing, valves, all that is correct you can throw them back on the car.

Have the linkage fully disconnected and get the car to idle with the base turn settings of the mixture screws. Once it idles you can start to sync the carbs with the syncrometer. Once you have both sides equal it is time to put the linkage back on and ensure the idle does not change because of this introduction. Both sides should still be set to the same measurements. You can then set the the throttle to different points and check both sides stay in sync. open the throttle to 1800 - 2000, check both sides, 2500 - 3000 check both sides. By doing this you will know your linkage and carbs are in sync through the throttle range. You want to make sure this is correct so you can start to tune the carbs while driving with different jets.

Step one is mostly done. I think I did a pretty good job cleaning everything and the service kit just arrived. I’ll button the carbs back up tomorrow and get after the valves and timing.

Couple

More

Photos

Love the garage wall - like the repurposed / barn lumber look

Car not to shabby either

Wile you have it all apart - note the size of all your jets and the Venturi’s - you’ll need to know these if carb needs tuning later. You may have to take the venturis out of the carb body to see marked size.

Here’s the fuel pump and filter.

And here’s the pressure regulator

Thanks Superhawk996! Noted on the jet sizes. I’ll do that! I can see 28 on the Venturi’s

Wow, those 'snails' have doubled in price since I bought one

Looks like an old Facet fuel pump. You might want to test it for pressure, before and after the pressure regulator. Ideally, 3.5 psi is adequate for your application. You may not need the regulator

Good reading: https://usermanual.wiki/Document/WeberCarbu...1746466219/view

You could upgrade the FP to a CB rotary which will consistently deliver the proper amount of pressure. It will also clean all 3 of those items shown as it also comes with a fuel filter in line.

You should be good to start with the 28s. It will give you the easiest time dialing it in. Once you have a consistent AFR from cruise to WOT then you can adjust you power band by moving up in venturis.

Only other suggestion is to upgrade the Dizzy with a pertronix Svda. The advance will definitely help smooth transition from rest. Only thing better than that is a 123ignition.

I'm think of building a kit to help others dial in their carbs. I have several jets and vents. Try out the different ones. Find the set that makes it work and send the kit back.

Nditiz1
great idea the Jets and Emulsion tubes add up quick

Man a tuning kit would be the cats pajama’s.

I was always torn between 28 mm venturis (great day to day driveability on a 1911cc with a moderate carb cam) and the 30mm venturis that opened up the top end (4700 RPM+) but at the expense of initial tip in response.

You’re in a great place. I was afraid you’d find 32’s or something even bigger.

Thanks for the comments and advice guys. Here’s my plan as of now.

Carbs are cleaned and I have a rebuild kit with gaskets, o rings, float needles (forgot to order the top gaskets for under the air filters, ordering now) and I’m going the put them back together noting the jets. Install as is for now.

Put a new fuel filter in (same type) and test the pressure before and after the FPR. I may change this setup to the one suggested and may reconnect the return line back to the tank.

Timing and valve adjustment then tune the carbs and see how it drives.

It was a busy weekend and i didn’t get as much time as I would have liked to work on it.

Thanks again!
Steve