Finally back on the road after over a year but with issues....

[tjp]

I run a 70 1600 that has been stroked, bored, decked, with a balanced and blueprinted rotating assembly (U20 rods all within 10 grams of each other, flat top pistons, lightened flywheel but not to total competition specs). Col. Joe race prepped head with Dean's roller rockers, one piece beehive springs, larger valves and 40 DCOE Webers. I run a five speed transmission. Compression at 12.76/1. Displacement just over 2 liters.

I had RustyRoadster's carbs tuned to near perfection before I pulled them. The A/F meter was near perfect in the upper three gears in all PRMs. She ran a little to a lot rich in 1 and 2 and I never got to sorting that out two fall seasons ago.

I pulled the carbs early last year to replace some gaskets to deal with some seepage from the bottom tank lids. After I reinstalling them I was getting fuel pissing out of the front two stacks. I finally figured that issue out last weekend, over a year later. FFS

I finally got her running with some serious swearing and cranking and now the idle is set and runs rough at 1000. Near as I can figure the fuel pissing and seepage has been solved. (I hope FFS)

Fuel at start up today was half a tank of 110 that had been sitting for over a year. I topped the tank with 110 once I’d let her idle for about 20 minutes to make sure the fuel seepage and pissing was solved (again...I hope. FFS)

Issues:

Back two carbs are pulling 10 on the snail and the front two are pulling seven. I fiddled with both the idle speed screws and all four idle mixture screws and am unable to change these numbers. Am I missing something?

Idle tended to surge. This was before I topped the tank with fresh 110. NO clue if the fuel would affect this. NO choke cables in use and the throttle cable is loose enough to not be affected by heat. I did not check the idle after topping the tank with fresh fuel.

First run at speed was ok until about 4-5000 rpm then I was getting some hesitation. Downshift to third for a stop sign and a got a loud backfire out of the tail pipe. I forget, is this rich or lean? I pulled plugs 1 and 4 and they both were black but not greasy or overly sooty.

Drive back after turn around was more hesitation, a little power loss and what sound like small backfires in the pipe under me (not at the carbs or tail pipe).

Thoughts please?
thanks

[Gregs672000]

Check your accelerator jets for function (remove jet or use a mirror to check down the throat while actuating the throttle). Backfire is lean, loss of power and hesitation is lean if it surges. Remove the screw cover that exposes the throttle plate and the slow speed feed holes and make sure it's clean (carb cleaner or compressed air). Things gum up! You said it was leaking fuel... how did you solve this, by adjusting the float level? If so, float level is critical to carb function and how the emulsion tubes operate. Changes here could lean out the carb too. What did the wideband say during your issues?

[Gregs672000]

Regarding balance, the linkage between the carbs could be preventing any adjustment as its pretty much air intake past the throttle plate that you're reading.

[Gregs672000]

I'm only familiar with U20 linkage, so I don't know how you accomplish balance on an R engine set up. Nevertheless, where ever they connect to each other is controlling what you're seeing on the Snail. The individual throttle screws won't have any effect as they're being over ridden (except that you can probably increase rpm but not change balance). That much off effects your engine a lot. Post pics of linkage if you can.

[baxtersit]

I'm running DCOEs on a stroker and it's been an adventure. Reading your post I think the bulk of your issues stem with the sync issue between the two carbs so until that is resolved you're going to continue to go crazy. Not sure why it doesn't change so I'm no help there. Idle mixture is very sensitive and I had some recent popping on deceleration that went away when I leaned out the screws 1/4 turn. Do you know your jetting? Emulsion, air, main and idle jet? Post that. Thanks and hope to be able to help. g

[Gregs672000]

Tim, the more I've thought about this the more I think that you have something(s) obstructing your fuel cuircuit (s), whether it's a plugged accelerator cuircuit or a slow speed or high speed pathway issue. Remove all your emulsion tunes, spray carb cleaner down every cuircuit and pathway, check each accelerator jet by blasting cleaner through the top so it squirts out the jet (don't blast yourself!), and make sure everything is clean. Also, as said you must resolve the imbalance issue... it simply won't run right that far out of balance. You only need to check the inner two throats for balance. However, if your carbs have an air bleed (some do, some dont... the Dellorto are factory sealed but can be accessed behind a cap to fine tune idle airflow) and you find differences between the throats on the SAME carb then consider that. Some differences could be due to a cylinder that is not working the same as the others (down on compression or poorly sealing valves) but unlikely at this point. Also, check all plugs, not just one for each carb as a plugged cuircuit will show up only on that cylinder. I recently posted pics of my plugs that showed one injector set was not firing consistently (2 and 4)... a wiring issue instead of a jet, but the same result. Also, your wideband is a great tool but also reads all 4 cuircuits and an obstruction may not always be as easily seen as reading a plug.
I'm happy to help in any way I can. I have several books I can reference if needed... that is until I sell my Dellorto set up... the new owner will get all of my 34 years of carb stuff!

[Gregs672000]

Tim, also consider trying Boostaine for an octane booster (I got it off Amazon). It is very effective from what I've been able to find, and economical vs finding race gas. My goal was to turn the 93 we have here to 97 or so for the 11.7 compression I used to run and control timing carefully, but I decided to drop compression and shouldn't need it. You can mix it to make just about any octane you need.

[Gregs672000]

One last thought... don't get on it hard until you resolve the fuel delivery issue... at that compression you don't want a lean cylinder... detonation happens FAST.

[tjp]

.....where ever they connect to each other is controlling what you're seeing on the Snail. The individual throttle screws won't have any effect as they're being over ridden. Post pics of linkage if you can.

I had linkage in the back of my head. I bet I didn't get them reconnected correctly when I put the carbs back on the engine. I'll be checking these first.

Tim, also consider trying Boostaine for an octane booster (I got it off Amazon)

I can get 110 a block from my house in this pissant town I live in so as far as octane goes I am set. I also have a proper octane booster I carry if I can't get at least 107.

Check your accelerator jets for function (remove jet or use a mirror to check down the throat while actuating the throttle). Backfire is lean, loss of power and hesitation is lean if it surges. Remove the screw cover that exposes the throttle plate and the slow speed feed holes and make sure it's clean (carb cleaner or compressed air). Things gum up! You said it was leaking fuel... how did you solve this, by adjusting the float level? If so, float level is critical to carb function and how the emulsion tubes operate. Changes here could lean out the carb too.

Carbs are clean inside. They didn’t have a lot of miles on them. As for the leaking issues, I had put new gaskets on the bottom tank lid as well as new gaskets on the top panel since it was removed. I replaced the needle valves since I have the carbs open. The fuel out of the stacks was caused by the new needle valves being a different size and too big. I learned that needle valves are also different sized.

What did the wideband say during your issues?

I am not yet running the A/F meter as the last one died. I have a new sensor and will be putting it in tomorrow as long as I can get the old one out....

[Gregs672000]

Sounds good Tim. So you have the correct needle valves in now, and float level was not changed... good. After you get them balanced again, if you continue to have problems consider that you can still have some missed grit. I've messed with accelerator jets a lot and found that it takes very little to interfere with their operation.
The burbling sound you heard does sound like carb balance.
Hope it all clears up!

[redroadster]

How much for 110 octane ?
Where did you aquire that ?
The ign timing centrifugal advance if stock
Is tricky to work perfect .
rich fuel may cause carbon tracking , make sure it's not over heating low coolant