I drove it home from the dealer last week - 125 miles with noproblems. Car was warm at the dealership when i got it.

Went out of town on business for a few days.

I can get it to start, but can't get it to run right. I (mistakenly) thought that the black handlever on the floor was a choke, so I used it like a choke, and it still didin't run right. I ran out of time this am and had to take my daily driver, but even after about 15 min of struggling, it still wouldn't run right! (shouldn't it have been warm by then, or does it stay flooded for that long?)

Anyhow, I've operated a car with a choke beforew, but it was set with tha accelerator, and the car automatically moved of the choke as it warmed. I'm told now that these carbs do not have a choke (is that true?)

My question: How do I get the car to run right?

Being as I have yet to drive the car since picking it up, I must say I'm a bit discouraged!

If anyone is bored and wants to call me now to teach me instead of by email, my # is (215) 328-2029 (daytime work, east coast time). Also, you could shoot me an email franck_skobieranda@merck.com
and I can call you.
Thanks, Franck

 

Hi Franck..!

OK - first bit of advice is don't play with the needle settings, air by-pass screw, etc. Leave those alone, OK?

My guess is that the idle jet(s) are clogged - which is typical if the carbs have been disturbed as they probably were at the dealer if they were worked on - or even a fuel filter was changed. To check them - I want you to do this...

Start the car - and it will have a "lumpy" idle. Then, with a stubby flatblade screwdriver (there isn't a lot of room) - loosen each of the idle jet screws ONLY 3/4 of a turn, one at a time.. If the engine idle DROPS - then that Idle jet is fine. Find the idle jets when, if you loosen it - the idle speed picks up (you are freeing the clogged circut).

When you find the jets that are clogged - unscrew them all the way (and watch for the rubber o-ring that should be around the screw - don't lose it!). Next - pull the actual idle JET out of the screw housing (it pulls out). Then - clean it out (i.e. - blow throgh it with compressed air, a jet spray of Gumout - whatever.)

Do this for each jet that is clogged.

Also - check that you have a CLEAN fuel filter (I have 3 on my carbed P'cars each - one main and two small filters before each carb housing).

My guess that's the problem (a clogged jet(s)). If it doesn't solve the problem - write back, and I'll walk you through "Step Two" on how to check the idle circut, the floats, the pressure, set the needles, etc. Carbs are a blast when they run right - but a PAIN when they don't... Unfortunately - the tendency fo folks is to play with the air/needles to compensate for a simple problem. When they do that - the carb is thrown out of sync throat-to-throat and side to side balance is then gone as well. In other words - you'll have to re-tune everything if you start playing with the basic settings...

Oh - the reason that it runs with your choke is that you are dumping fuel into the circuit that has the clogged jet.. It isn't an "elegant" solution (you are flooding the good systems by forcing them to take more fuel - but it does work in a pinch

Best to you..!!

 

The black lever on the floor is the hand throttle, used to maintain a higher rpm, while the car warms up. You use it after you have the car fired.

And as John said youll need good fuel filter(s) and after youve installed some good filters get to work on cleaning the gunk out of the idle and main circuits, dont change any setting just yet

good luck !!!

 

Been there Done that! if you can call me and Ill tell you what I had to do its a little detailed to go into typing you know what I mean
505-442-9079

 

Thanks to you guys so far.
I appeciate your help.

Jim in New Hampshire:
1) Does the idle jet problaem happen "all at once"?
Like I said, I test drove the car in mid-March - just fine.
I bought it and drove it home x 125 miles on 4/3/02.
Boom! - prblem started "all at once" yesterday.

2) Do I check the idle jets with the car cold or at OT?

3) I see two small, clear housing fuel filters, immediately upstream of each bank of carbs. Where is the 3rd filter? Please tell me its not in the tank!

4) Where do I find the idle jet screws? I've never worked on Webers before.

5) Before I got your email, I went out ot futz with the car a bit. Started it with some pedal pressure with cranking - no problem. used the hand throttle to move up idle speed after starting, for like 3 minutes, then moved the throttle to the floor. Went for a short drive. Everything went fine for 10 minutes / 3 miles of suburban driving. The first time I pushed on the gas coming out of a turn, the car stumbled, and continued to stumble for the rest of the 2 mile ride back home, with any appreciable accelerator pedal pressure.

Any ideas?

Tim-
Like Jim advised, I promise I won't mess with settings!

Jim in New Mexico - I will try to call you!
Franck

 

[quote]Originally posted by Mein 14:
<strong>
1) Does the idle jet problaem happen "all at once"? </strong><hr></blockquote>

It could... If the car was sitting for a while - the bowls are down on fuel - and when they fill - you are moving any contaminants through the system - and any particles (and I mean SMALL" particles!) - will clog the idle jets.. If you find a clogged jet - you'll scratch your head as to how something that small can cause such a BIG problem

[quote]<strong>
2) Do I check the idle jets with the car cold </strong> <hr></blockquote>

Preferably warm. It's easier to hear the change in the idles as they are unscrewed and the engine reacts better to small fuel changes..
[quote]<strong>
3) I see two small, clear housing fuel filters... </strong><hr></blockquote>

Yep - those are good Also - you should see a filter either on the left hand engine compartment shelf or just aft of the front tank (POs have been known to put filters anywhere in-line

[quote]<strong>
4) Where do I find the idle jet screws? I've never worked on Webers before. </strong><hr></blockquote>

OK - on the outside "side" of the carb body, you will notice a number of 10mm bolt heads, and a screw with a spring around it - don't touch any of those Near the top of the carb body - you will see 3 BRASS head screws for a flat blade screwdriver. There is a screwhead for each "throat". These BRASS headed screws are the ones you want to try turning out 3/4 of a turn....

[quote]<strong>
5) Before I got your email, I went out ot futz with the car a bit. Started it with some pedal pressure with cranking... </strong><hr></blockquote>

To start your car, if it has been sitting for a while and is stone cold - let the fuel pump run for a bit (about 10 seconds) - then depress the gas pedal (pump) twice - and fire it up. By running the fuel pump - you are filling the bowls and priming the carb circuits and filling the gas-line/filters with fuel...

If the car is warm - DON'T pump the gas pedal (usually) and depress it and start the car...

Anyway - I hope this helps!! Also - while you are in there (engine compartment) check that your plug wires are properly seated and everything is tight/connected on the ignition/distributor. With your long description above - it also sounds like a plug wire may be loose? So check those as well, OK??

 

Sorry about not posting my experiences....
I've been doing a few things nightly & then driving the car to check to see if the problem was solved. Two out-of-town business trips, plus my wife's birthday present to me (freedom last Saturday to go to the Hershey meet) hasn't helped either!

What I 've done so far:

1) I checked the operation of the idle jets when the car was up to operating temperature. At baseline, all 6 jets were fully screwed in. Loosening each jet failed to make the car stumble for 3 of the 6 jets, so I just pulled them all and cleaned them. I pulled each jet out of the screw holder and blasted them with Gumout - for a few jets, the blast of Gumout changed from a weak spray to a strong spray. I cleaned them along the long axis bore of each jet, and also the intersecting bore that goes across the jet

No change from this service.

2) I replaced my fuel filters. There is no engine compartment-munted fuel filter in the car (my car is an E originally - wasn't that a fuelie with a compartment-mounted fuel filter?), but there was a small, translucent plastic filter just upstream of each carb. The filters had no brand name or part #. I replaced both filters with glass-barrelled Purolator filters that matched the inner dimeter of the fuel line.

No change from this service either.

I have also observed a few more things, but don't know what to make of them:

1) Now that I know how to cold start the car, it runs fine while fully warmiing up. In fact, the first one or two hard accelerations after a 5 minute warm up period seem to produce the full power and smoothness I experienced during my initial drive home with the car. However, in subsequent accelerations, the car chokes & stumbles with any appreciable throttle input (the more gas, the worse).

2) If I'm coasting in a straight line, and I give it, say, 50% gas, it stumbles a certain amount. However, if I'm cornering and give it the same 50% of gas coming out of the corner, it stumbles more prominently, coughs, and backfires multiple times.

Again, any help is greatly appreciated - maybe buying a 31 year-old carburated 911 was stupid!
I haven't touched a carb since I worked on my Dad's lawn mower as a 14 year-old! <img src="graemlins/crying.gif" border="0" alt="[crying]" />

 

ttt

 

Not that I have ever tried, but I have read a few times of people with rusty fuel tanks having such a problem.

The rust blocks the fuel line output (there is a strainer, apparently - it blacks that).

Can you check the tank for rust?

One last thing - does the problem now only occur when the engine is hot - ie, fully up to temp but not a problem before then? If so, I had many problems with this until I tested my ignition wires.... I had a Beru connector which would stop conducting when hot.

Cam

 

Hi Cameron-
Wow - I've never met a New Zealander before!

Yes, the problem is present cold, but more present at OT. I think I need to go through the ignition (cap, rotor, wires, plugs) as well as fuel delivery.

Now the township has torn up our street, so I can't drive it anyway. This is like having a supermodel in the bedroon, and you've just locked yourself in the bathroom!