I have just gotten my car running after 4 years in restoration. It runs well except I have this issue with the idle speed not staying the same. Seems to get worse when hot. Does not happen when given gas. Thanks

Submitted by DavidBarnes71@… on Wed, 05/29/2013 - 19:56

I will add my experience to the other folks here. With the exception of floats leaking in my Strombergs the problems I originally trouble shot as carb problems turned out to be air leaks instead. The one that stumped me the longest was the gasket leak where the cross-over pipe on the 68's mates to the top of the exhaust manifold. Check every place you can think of where air might leak into the intake system.

I also had a spark plug carbon foul and cause mis-fire problems due to what I assume now was a very rich condition caused by a leaking float

David Barnes
68 E-type FHC

Submitted by ckrop@aol.com on Wed, 05/29/2013 - 13:29

It smooths out with choke or throttle.I plugged the vacuum line coming out of intake and that didn't help.I will double check gaskets. Thanks for all the suggestions

Submitted by NC47-47501 on Wed, 05/29/2013 - 11:58

I have a similar issue with my 66 coupe. Smooths out with a little choke but never quite right. Different size metering rods worked with another of my cars and am planning on trying the same with this one. Is there an easy way to check for a vacuum leak as Tom mentioned?

Submitted by hilstonsmg@aol.com on Wed, 05/29/2013 - 01:06

I've had SU's on cars for the last 50 years, even had one on a Harley and have tryed damn near anything for dashpot oil. Marvel Mistery Oil, ATF, 3 in 1 oil, and in my youth the distiled sweat of virgins. Most of the books recommend 20 or 40 wt. motor oil and that has served me well all these years. Other guys swear by their choices, just make sure you have enough and give something else a shot if you must. The virgin sweat is hard to find these days and my wife would kill me if I looked. Drive it like you stole it...............Don

Submitted by bonnettoboot@e… on Wed, 05/29/2013 - 00:32

The oil used in the dampers depends on the climate. In cold winter climates -such as in Scandinavia- it needs to be 10 or 20. In hot summer climates -such as Los Angeles- it can be 40 or 50. I have always used 40. As for transmission fluid, Volvo - who used SU's on its early cars- suggested using it instead of motor oil. Perhaps some of our Nova Scotia members could tell us what they use in winter.

Submitted by DavidBarnes71@… on Tue, 05/28/2013 - 20:31

I have always used automatic transmission fluid in place of the official SAE 20 engine oil called out in the manual for the Strombergs on my car. I heard it as a suggestion years ago from a guy who had done a lot of work on older Jags. Has worked fine for 10+ years. I will let other folks correct me if it does not work well in SU's.

David Barnes
68 E-type FHC

Submitted by SE09-51114J on Tue, 05/28/2013 - 20:19

They actually make a damper oil. however, what they say in a pinch is 20 weight oil only. I can never find 20 weight oil. SNG Barratt does sell the damperper oil, but it will take a while to order and ship. Our V-12 had the same problem wben we got it and few drops in each carburetor did the trick. Check out your owners manual and I'm sure it will advise you accordingly. Not too muxh, not too little...
Let me know how it works out.
Cheers!