HELP!! SU carbs suddenly..

[beandip]

First of all if the piston rises and gets stuck , the butterflies are connected to the linkage and if you let off on the throttle the air is cut off to the engine. The butterflies controll the engine speed the vacuum piston only controlls the fuel mixture . So sticking vacuum piston couldent be the coulpret here. First check on binding linkage or weak return spring. WHAT ARE WELAND COVERS ? sorry but I have never heard of them on anything much less SUs . I don't claim to know all but this is a new one . Gary

[sakijo]

WHAT ARE WELAND COVERS ? sorry but I have never heard of them on anything much less SUs . I don't claim to know all but this is a new one . Gary

I think it's WEIAND - Auto performance parts and accessories. Their logo was a big W with WEIAND across it. Have not seen much of their product in years.

[astrohog]

1 bravo 6 - thanks, but, yes, oil level is fine!!

Zeiss 150 - the problem does NOT go away when I tap the pedal. I very well could have some kind of vacuum leak as all the hoses and lines are all original. I will do some closer inspection of vacuum lines.

kenz240z - I have inspected the brakes (and replaced the rear shoes!!) Have not got to bleed the lines yet (no brake bleeder and no helper as of yet!:mad: ). You offer very good advice on the flex lines. I will do that next!! Coolant system/radiator was next on my list. As I do not have a garage here at home (hopefully get that built next spring??) I am getting ready to store my Z for the winter and start on her again next spring.

Beandip - I will try to get some pics of the Weiand covers for you. I think they are cool looking (and (after-market) period-correct), but have been told the stock airbox is probably better, so as soon as I get the stock box cleaned up, it is going back on! The mech linkage seems fine, but I will have to re-check all of the springs as they are all old and should be replaced.

WOW! Thanks for all the suggestions guys, I sure appreciate all of the support!!!!

Regards,

Jeff

[sblake01]

WHAT ARE WELAND COVERS ?

As Sajiko said, he means Weiand and by 'covers' he means air cleaners. Weiand wes a big time speed equipment company that had been around for years and, like as is the sign of the times, they've been bought out by Holley as they've bought out a lot of the old school high performance names like Hooker Headers, Earl's etc.

http://www.holley.com/index.asp?division=Weiand

[240ZMan]

I would focus my efforts on the throttle and linkage. It's hard to imagine a vacuum link that would provide enough air to cause the car to keep accelerating beyond 80 mph! And to Beandip's point earlier, even if the piston wasn't falling, with the throttle closed your engine would not continue to accelerate at that speed.

If you can get your buddy to help, one of you should look at the linkage while the other sits in the car and floors the accelerator. Do this with the engine off:) You're looking for something that could cause the throttles to stick open. Let us know what you find.

[Arne]

Hmm, you know, I've seen cases where one of the pair of carbs will have the throttle lever catch on the choke linkage and hang there. This could definitely cause this type of thing.

I know Bryan won't mind me messing up a copy of his picture for a good purpose like this. Look closely at yours where I have circled in yellow.

[beandip]

As Sajiko said, he means Weiand and by 'covers' he means air cleaners. Weiand wes a big time speed equipment company that had been around for years and, like as is the sign of the times, they've been bought out by Holley as they've bought out a lot of the old school high performance names like Hooker Headers, Earl's etc.

http://www.holley.com/index.asp?division=Weiand

I remember Weiand the made intake manifolds and Heads for the old Flat head Ford engines . I haven't seen or heard of them since the late '50s . I stand corrected . After so long I didn't even remember the name. Gary