engine and drivetrain Weber Dcoe 45 Sidedrafts - Fuel Dumping Out Of The Horns

[bruno615]

Hey guys,

 

I recently completed my engine swap (Swapped in a stroker M10 with dual sidedrafts).  For a while, I had been driving the car around without issue.  I had some minor issues of running one 2 or 3 cylindars at idle, particularly at cold start, but everything else was generally fine.  

 

Then, one day while I was out, I went to fire up the car and could only get 2/3 cylinders to fire.  I had to limp home.  I eventually found that the issue was that cylinders 3 and 4 weren't getting any fuel.  Upon cracking open the weber, I found the ball bearing of the needle sitting in the bottom of the fuel bowl.  It was odd to me, as I would expect that this would cause fuel to rush into the jet unobstructed.  I tried putting the ball back into the needle, but that's when the carb started gushing fuel instead of lacking fuel.

 

I ordered a new needle jet.  Instead of fixing my issue, the gushing fuel continues.  (Though the car WAS firing on all 4 cylinders)  The air horns are on tight, and gas flows out of both #3 and #4.  I am at a loss of understanding what could be going on here.  What else could it all be?

 

Mike

Edited December 20, 2013 by bruno615

[M3M3M3]

step back and think about what is happening.  carbs are pretty simple when you just follow the fuel path.

 

fuel coming out of barrels.

how does fuel get in there? what is between the pressurized fuel line and the barrel?  something in there is open or leaking.  how would the ball bearing get out of the needle?  did you reset the float level after putting the needle in?  sounds to me like the float tab is bent causing the needle valve to be open to fuel pump pressure either all the time or enough that bowl is overflowing.

[Preyupy]

Are they brass floats?  If they are, take them out and shake them.  If you hear fluid splashing around inside, replace it (it's not "floating" any more)

[mike472]

Almost positive your floats are full of gas.  Get plastic versions for replacement if thats what it is.

[Hans]

Doesnt that ball sit on a spring in the valve? Might it be in the bowl too?

[bruno615]

Both floats are plastic.  I didn't try shaking them, since they were plastic, but I'll try it when I tear the carbs back down this weekend.  (The brass floats on my Honda CL350 DID have leaks, so I know what to look for)

 

The float height looked equal to the other sidedraft.  I'll measure them this time, and set the angle if necessary.

 

Myrtle - I have no idea how the ball fell out of the needle, but I think it was clogging it, and then popped out when I opened the carbs initially.  Once I put it back in (with the spring), the problem became too much gas vs. none at all.  Swapping the needles didn't have an effect, so I'm going to check the floats for gas, and then set them properly.  

 

Thanks for the ideas everyone, I'll report back!

 

Mike

[TobyB]

Annoyingly, many of the plastic floats are foam, so you have to weigh them.  I forget the right weight...

 

Here's another easy test, when you have the lid off.  With the lid held vertically, float dangling

freely, blow into the fuel inlet.  Then tilt the lid slightly to 'raise' the float.  Your air should be 

100% cut off.  Easily.  I bet either your levels are way off OR the float valves aren't sealing.

 

Only other thing it could possibly be is very high fuel pressure.

 

t

[2002day]

Where are you located? If you are in SOCAL, Matt at Ronin in Fullerton is the side draft master. Especially Webers. He just dialed my Mikuni Side drafts in, basically Webers. I'm sure he will help over the phone regardless if you can take your car in. This is not an endorsement to the shop in any way, I am not affiliated, but sometimes its just best to go to the expert right away, save you some gray hairs....I know I've lost some of mine going back to Briggs and Statton go-cart carbs when I was 13. And them are as simple as a steak on a grill.....

[downhillwolf]

I suggest you look the back cover where the spring is attached to axle. Maybe there is a leak...
I had once the same problem, there is a pump cirut pin that was missing from the hole and the fuel was leaking trough the axle...

[Hans]

You'd thing excess fuel pressure would affect both carbs. That said, a regulator is not t bad idea with DCOEs - about 2.5 to 3 psi. works.

I'm trying to imagine how the ball came out. Did you use a fresh sealing ring with the new needle jet?

[bruno615]

Sure enough, my float needle wasn't set properly.  It was sitting around 11mm.  I bent it back to a little more than 12mm and I ran around all day on Saturday without issue!  Still have to put in a larger exhaust and header for the engine, but here's the car idling!

 

Mike

 

[M3M3M3]

yeah! thanks for posting the solution.

[bruno615]

For those looking for more info, check out this video (I wish I had seen it before I started!)

 

 

DCOE 45's are supposed to sit at 12mm from the centerpoint, measuring from the end of the gasket.  

 

Edit:  I used a measuring tape and vice grips to do mine.  Make sure you are ONLY bending the tab, not the rest of the float!  I took the float off, clamped the vice grip on the tab, and pushed the hinge portion in the necessary direction.  Did this 4-5 times till it was perfect.  Go slow and measure every time.

 

Mike

Edited December 30, 2013 by bruno615

[mikebontoft]

hmm what cam do you have in that anyway?

[eurotrash]

What's that sound!?