Blaine, I just remembered something...when the motor is cold and I open up the throttle (even a little) I saw fuel squirt out the accel pump jets. When the motor is up to temp, I remember doing the same and fuel trickled out or I could not even see it at all. Have you tried this? What happens in your case? If this still holds true (I haven't checked this out in a while), then when cold the accel pump is working normally and the richness in the mixture is good when motor is cold. When warmed up, fuel is not squirting out (evaporating?) and goes lean, until the main circuit can catch up. What do you think? Henry
Accelerator Pump Back Bleed Anyone know what this is? The list that I scanned in list all of these as 0.40 EXCEPT for a US car...it is 0.70. Is this something that can be changed? Is this a pressed in meterd jet? Anyone know what this controls? I can't seem to find it in the exploded view.
Thanks for the suggestion. Wouldn't this show on your flow meter when measuring airflow at idle? My carbs are now spot on at idle with 8 identical flow meter readings. But I will inspect the linkage to be sure that both linkages are consistantly and freely returning to the stop screws.
No. For the best carb synch possible, the idle synchronization process should be done with all interconnecting linkage disconnected. All carb air flows are independently of one another...hence your identical air flow readings. This is the key step. If the interconnecting linkage "picks up" one carb, or side before the others, your "off-idle" synch will be off. This will exacerbate any potential stumble issues, regardless of your transition mixture levels. Best, David
Ok just an update. I went to 210s ACs and I still had the bog off idle. I've since gone back to a richer idle mix (result was improved) and then today I installed 200 ACs and the bog is almost gone...the best yet. So for now I put the airbox back on. I'm pretty happy now with the way it's running. The other factor here may be the air temperature. It's about 50 f here and so I may have to re-assess and adjust come summer but for now I'm driving.
F-36 Emulsion tubes are for US emissions. Try a set of F-24's which are the tubes the engines were originally spec'd with. However, with the changes our fuel has gone through over the last 30 years, someone may need to create a custom tube. The progression holes are also different between US and euro models.
Have any of you guys with mixture issues considered getting an fuel/air mixture gauge? It wouldn't tell you what jets to use but you would know for sure if you were rich or lean and by how much. I was looking in to one of the Innovate Motor Sports LM 2 units.
I bought the LM2 single input & it helped my tuning. If I had to do it again I'd spend the xtra $$ & get the dual input or some other brand. Theres problems with the tach signal & I'd like to have an adapter to probe each carb individually. Bill
I opined the virtues of mercury over water versions elsewhere... This tool is the FACTORY specified tool for this job, as it will show problems in progression, balance, cam lobe center syncing, off idle lurch, etc... It is NOT an accident that this is a required tool... Just remeber, a ported signal, and a filtered line-that is dampened-so you don't let the engine inhale the stuff-tres toxic stuff is mercury...it is the best suited for the job, but requires much respect and experience in its use...
