Well, how timely- talking about Carb overhauls! I recently included the following paragraphs in my post about our Mid-Atlantic Imperial Adventure: -------------------- The mighty 413 ran smooth (no pinging with brisk acceleration) but needs a bottle & 1/2 of Octane Boost with full tank, but this allows the timing to be set close to factory specs (-2^ retard). There is a still a slight hesitation in the Carter AFB, (from stop) which may be just a slight float adjustment (Mixture screws reset per specs and idle is smooth at 565 rpm. The book says 500, but 500 in N put the idle in D at 475- just a bit too slow-with some vibration to the interior. 560 in N gives me 525rpm in D- no vibrations. My friend Bob also has a Jensen Interceptor with the 440 drivetrain. A few years ago, He bought an Edelbrock 600 cfm carb for it, but later, like I did, he put an Edelbrock 795 cfm on the 440. He gave me the 600 cfm carb to try on the Imperial. ---------------------- I was checking the Specs in another Imperial Tuine Up spec sheet, and it said that idle should NOT be below 500 in D--interesting- just what I said to myself. SO that confirmed my idle mixture adjustments and then 'idle stop screw settingts' were correct 'the moment'-- I am looking elsewhere for the source of the 'hesitation' (Other than the mixture adjustments). THis carb was 'recently' rebuiolt by a specialist sub-contracted by the Previous owner. So it 'should' be clean inside. The fact that I put 1989 miles on it soince May- confirm it's 'functional'. But it's not 'PURRFECT'... I have rebuilt many many carbs over the years. I agree 1,00% with Kenyon about the rebuild kits-getting then most comprehensive kit IF the 'opening' and thorough cleaning 'of the obvious' doesn't solve the problem. However, sometimes the problems are not worn parts but -as in the IML archives from 1948 on carbs: vacuum leaks, weak(dry or brittle or not as flexible) accelerator pump leather, dirt in orifices, or the winter/summer adjustments. Since writing the above, the temps have dropped drastically here in MD. I had to return the Imperial to the garage before the 1st snow (we had 8" BTW), and so I ad to move about 5 others to sequence the Imperial up the driveway & under the lift, putting its 'later Cousin'-the Jensen Interceptor 440 on the lift 1st. The CARB point here is that it was about 33^ the morning I started the Imperial. It started quick and oil pressure came right up. Throttle action response was instant. The hesitation was never at idle, only under load from a stop. Now, I don't like to just 'start, move and shut down' big pushrod hydraulic tappet engines; so I took the Imperial for my standard 8 mile 'loop' run. This brings everything up to normal operating temp, a 5 mile stretch at 65, etc. There was NO HESITATION That morning. The only difference since the 670 mile trip- was the Outside air temp. The choke obviously was working- more so than two weeks ago. I reinspoected my carb settings- the idle mixtures are -per the book- on the lean side of peak adjustment. Refreshing my familarities with the usual 'culprits': vacuum leak, base gasket leak, accelerator pump, float adj-- I am thinking maybe I'll wait a bit before swapping carbs--with salt on the roads right now- No Imperial of mine will be cruising for awhile anyway. So clealy this cold AM morning verified that the 'problem' is mixture related. Now more dense air usually means a weaker mixture, not a richer mixture, but of course the choke adjusts' for the air temp- making a richer mixture. ANother brain challenge- isn't that why we love these cars- keeps our intellectual faculties 'sharpened'??? Sherman D. Taffel Columbia MD (28^, 19^ this AM) 63 Crown (safe in the garage) ----------------- http://www.imperialclub.com ----------------- This message was sent to you by the Imperial Mailing List. Please reply to mailing-list@xxxxxxxxxxxxxxxx and your response will be shared with everyone. Private messages (and attachments) for the Administrators should be sent to webmaster@xxxxxxxxxxxxxxxx To UN-SUBSCRIBE, go to http://imperialclub.com/unsubscribe.htm