Rough Running w/ Dual Carbs, And now low fuel pressure too. Options

[Craigers17]

The little cheap ass round "tuner" gauges are notoriously inaccurate!

(IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/smile.gif)

Agreed, where is a good source for us CSOB's?

I'm not sure what you all consider cheap, but here's a link similar to the one I bought. It is made by Aeromotive and has a release valve built in. It has been very reliable up until now, and I'm not sure it's malfunctioning....I suspect the pump. More testing info to come.

https://www.googleadservices.com/pagead/acl...CEF0&adurl=

[Craigers17]

Thanks everyone for the additional input. The floats in the picture are pre-adjustment. They are more horizontal now, and they are pretty much level and not bent. As soon as I get it running again, I'll re-evaluate the float settings.

[930cabman]

Thanks everyone for the additional input. The floats in the picture are pre-adjustment. They are more horizontal now, and they are pretty much level and not bent. As soon as I get it running again, I'll re-evaluate the float settings.

Thanks for posting, all of this is good information for us backyard hacks (speaking for myself only)

[Craigers17]

So I wanted to post an update on this just because it's so bizarre. So I haven't touched the car in about 2 months....busy with work. In addition to the carb issue, my turn signals weren't working so I bought an E26 flasher relay from Spoke. Since I figured that would be a quick fix, I installed it this morning and the turn signals are working again as expected.

Since I was already in the car, I figured I'd give it a start since it's been idle for a couple months. It cranked right up and was idling great. So, with little optimism, I figured I'd give it a spin for a few miles to see how bad it was going to run. To my surprise, it ran great, but I needed gas so I got a few gallons and went to pick up some groceries. Ran it for about 10 miles. (no bogging down, no backfiring, complete power was back)

I did have some very small issues, but it mostly ran great. I'm pretty sure the issues I did have were due to the linkage on the driver side carb which isn't returning 100% correctly....the hole in the throttle lever that the shaft goes through is wallowed out a bit and it's creating a situation where the lever isn't returning as well as it should( I have a pulley system linkage & that's why that's important). That said, overall the car is running great.

The only thing I changed was the E26 flasher. Additional information is that I changed out the fuel filter the last time I fiddled with the carbs, but still couldn't get it running correctly. My thought there is that, MAYBE, there was water/mositure in the old filter and possibly the pump???? After having replaced the filter and giving it 2 months to "dry out", the moisture issue corrected itself???? I'm basically grasping at straws because I can't figure out why all of a sudden, it's running flawlessly.

Well, for anyone that cares, that's where I'm at. Thanks again for the help!

[Superhawk996]

There is no magic that accounts for the change in behavior.

Moisture doesn’t just disappear on its own - especially if it’s bound to ethanol. Water sinks to bottom of tank and can’t evaporate because it’s not exposed to atmosphere.

Like you said, your main fuel filter may have been partially blocked and changing that helped.

I know you cleaned carb jets but did you clean the inlet strainers that are in each carb? This can impair fuel flow. And of course there is the sock in the tank - make sure that isn’t blocked up. Over time, just sitting debris that was plugging these screens can settle, reopening them to flow until they have a lot of flow and the debris gets picked back up again re-blocking the filter screens.

Likewise, get that linkage issue sorted - you can buy new lever arms if a hole has become too elongated. Unsynchronized linkage will cause roughness.

[Craigers17]

There is no magic that accounts for the change in behavior.

Moisture doesn’t just disappear on its own - especially if it’s bound to ethanol. Water sinks to bottom of tank and can’t evaporate because it’s not exposed to atmosphere.

Like you said, your main fuel filter may have been partially blocked and changing that helped.

I know you cleaned carb jets but did you clean the inlet strainers that are in each carb? This can impair fuel flow. And of course there is the sock in the tank - make sure that isn’t blocked up. Over time, just sitting debris that was plugging these screens can settle, reopening them to flow until they have a lot of flow and the debris gets picked back up again re-blocking the filter screens.

Likewise, get that linkage issue sorted - you can buy new lever arms if a hole has become too elongated. Unsynchronized linkage will cause roughness.

Thanks for the reply. I'm fairly sure it's not a flow issue from tank or pump(at least not any more). At one point in my troubleshooting I removed the main fuel supply line from the "t" and set it into an empty gallon container...then turned on the pump....it was flowing freely. Also the tank and sock have probably less than 100 miles on them. I did remove and clean the inlet strainers as well.

Another thing I did today was cut the old filter open with a sawzall. I have attached a couple pics of "the innards". I'm no expert on fuel filter autopsies, but, to me, it looked pretty clean.....as if "crud" coming from the tank wasn't the probable issue... which stands to reason as the tank is almost brand new.(although the cross section piece in pic #3 might be a little suspect??)

For now, I'm going to replace the worn throttle lever(not sure I'm using the right terminology, but I've attached a pic) and finish tuning the carbs again.....this time using very small increments on each adjustment.

Fuel Filter Autopsy Pics:







Throttle lever replacements parts:

[Superhawk996]

I’m with ya’, that filter media looks fine. No obstruction there.

Agree - resync carefully. synchronized carbs make a big difference in smoothness.

[930cabman]

I’m with ya’, that filter media looks fine. No obstruction there.

Agree - resync carefully. synchronized carbs make a big difference in smoothness.

(IMG:style_emoticons/default/agree.gif) The media appears mostly clean, free from debris. Having your carbs synchronized is very important.