DCOE bog/hessitation

[Guest]

Pump is working good from what it appears. If you open the throttle up medium it's fine. If you snap it open at idle it dududududududRRRRRRRRRRRRRRRRRMMMMMMM's.

Single dcoe, 50F8 idle, 130 main 200 air correction, 50 pump jet, hole plugged in pump valve, timing @14 BTDC. Stock 1500 @ right about sea level. Any ideas? Funning thing is, my DGV didn't have this problem.

 

[hooey]

choke size please? what tubes are you running ,timing @14 at idle?
what is at when you at 4500 rpm?

 

[hooey]

the parts I'm talking about

 

[Guest]

F16 tubes and 30 chokes. 14 @ idle 32 full. Thought it might be that carb and put another one on and the same thing. Swithed to a 170 air correction w/ no change. Swapped to a F9 tube w/ no change. Both carbs are shooting fuel strong out the pump jets, maybe too strong. I'm wondering if it's a design flaw w/ the 1500 single DCOE intake as it would appear that maybe it's just shooting straint down the throat of 2 and three and 1 and 4 might be too lean and stumpbling. IIRC, I read somewhere that these manifolds do that.

 

[hooey]

timing is ok , try some smaller chokes
what I here you saying is that if you go slow when you crack the carb open it ok but if you nail it it fall flat
going down on the chokes will help that problem
what is going on is that the carb is not making vaccume
to get the main jet to come into play that is where I would start maybe some 28mm


https://www.piercemanifolds.com/
try them for parts

 

[Guest]

Some 1500 guys are running 32-34's in a 45. I would think I should be able to make some 30's work in a 40. I have thought about dropping down the aux to 35 to help it out. One of the venturis is kinda loose in the body. Carbs are like brand new.

 

[Guest]

what is going on is that the carb is not making vaccume
to get the main jet to come into play that is where I would start maybe some 28mm

The duration of the pump squit is pretty long. It's longer than the bog. I would think the juice should pull it through that.

 

[hooey]

put a vac gauge on it to see if that is what your problem is your going to use this on the street and not just racing it right ya I have seen people use larger but I bet there having the same problem

PS have you ever tryed to run your motor with a eye dripper
that what your doing with that pump jet don't work real well dose it

 

[Guest]

Not racing, steet car. No vac pots anywhere.

 

[Guest]

Hye Doc, where y'at? I know you have some of these things on your stuff.

 

[hooey]

No vac pots anywhere.

you got a drill and tap make one then plug it when your done

 

[JPSmit]

hey Billy SU! (just saying')

 

[Guest]

I don't like 'em. I can live w/ it, it's not bad. Most folks probably wouldn't notice. Gonna try a stronger spring on the piston. I'm really suprised it squirts in a straight single stream like a garden hose. IMO if it sprayed it would work alot better. It squirts a single stream about 18" long which would be straight down the throat of 2 &3. Anyone make a pump jet that shoots a mist more like an injector for these?

 

[hooey]

https://www.piercemanifolds.com/SearchResults.asp?Search=76801&Search.x=0&Search.y=0

maybe go biger on the pump jet but I still think if you whan it to not bog go smaller on the chokes so the carb works and you not feeding it with just the pump

 

[BlueMax]

What you are experiencing is a common condition due to your progression idle ports. Most people will buy a DCOE off of EBay or from a buddy not realizing that each carburetor progression ideal ports were machine for that particular application. In your case I’m sure this is what has happened. The 40 DCOE 18 is used for the twin cam Lotus Elan and Cortina. At this point you will not find jetting or choking will solve your issues. You may want to chat with John or send your carburetor to him to fix your problem!
https://www.youtube.com/watch?v=WBrmABBIDJc

 

[Guest]

These were a twin kit for the 1500. I have some off of a '74 Alfa. They have three holes where my other ones are and another one off to the side. is this the 4 port carb? The other holes isn't the feed hole from the idle mixture needle. I don't know where it goes yet, haven't torn it down.

 

[DrEntropy]

Try the smaller chokes first. Don't go goofin' with th' pump/jets. It's <span style="font-style: italic">supposed</span> to be able to put yer eye out at twenty paces.

If it is a slight bog after the engine is warmed up, the smaller I.D. chokes will help. There's very little difference in the two e-tubes you have, IMO that's not the issue. Max hit it with the progression ports explanation, methinks.

And I got a good laugh at the last comment after that video: "Wow brave work i've been told by loads of people never take these apart cos they will never be right again! "


*SNORK!*

 

[RichBall]

Don’t know if this helps, but here is a list of suggested settings for the Weber Dcoe on the triumph engine in a spitfire. I’ve read a couple places that to tune these correctly you really need to do it on a Dyno (rolling road). No experiance, just what I've read. The list came from this website.
https://www.totallytriumph.net/spitfire/engine_building.shtml
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Here is a list of suggested settings for twin DCOE carbs on a Spitfire, these are initial settings and may be fine tuned by the rolling road. They are much the same for 1300 & 1500s.
.........................Twin 40s ........Single 45
Choke tube:... .......30 ..................33 .......£10 each (2 per carb)
Aux. Venturi: ........4.5 .................4.5 ......£15 each (2 per carb)
Main Jets: ............115 ................190 ......£3 ................."
Emulsion Tube: .....F16 ................F9 .......£3 ................."
Air Jet: .................155 ................175 ......£3 ................."
Pump Jet: ..............35 ..................40 .......£3 ................."
Idler Jet: .............45F8 ................45F9 ...£3 ................."

 

[Guest]

From what little I read, the aux venturis dictate when the mains come on line. Here's what I don't understand, if these are the cars for a dual set up, why will I need smaller anything if I use just one. If two cylinders don't make enough vacuum, I don't see how one could. I do see where on a dual set up that each cylinder would be getting the full blast from each pump jet. I should have eceything to put them both on, but I'd hate to do that to a worn out low compression street motor that is just a cruiser.

 

[DrEntropy]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:] Here's what I don't understand, if these are the cars for a dual set up, why will I need smaller anything if I use just one. If two cylinders don't make enough vacuum, I don't see how one could. [/QUOTE]

How 'bout this... only ONE cylinder is drawing at a time. But it's drawing thru an intake with volume for TWO... A 40 DCOE is capable of 400 CFM at WOT. More than adequate for that anemic li'l 1500. Try some smaller choke tubes.

The venturi should NOT be loose, they should be held in place by a pair of trumpets on a DCOE 18.

And who cobbled an Elan to have a set of Webers?!?! *sheesh*