Dcoe40 Throttle Sticking

[mattius]

Been struggling to tune my webbers recently and discovered that the throttles are sticking slightly about 4mm from the base, 

 

Before i strip them down has anyone any thoughts as to why? or am i doomed to strip them off?

[Nick Jones]

Check the linkage first and make sure it's all lubed up and moving freely.  Assuming it is not linkage related - ie they stick even with the linkage disconnected - sticky deposits of fossilised hydrocarbons from lack of use........

 

Dosing spindles and throats with carb cleaner, then penetrating oil on the spindles may work if it's not too bad - though thinking about it Webers have ball bearings so you don't want to wash the lube out of them.

 

Nick

[Triumph-V8]

The accel fuel pump might stick, accessible from the little

plate between the two runners at the front.

 

Also the bearings might be the culprit,

quite easy to change.

[aoie]

My  35+ year old Ebay DCOE  purchase had the bearings shot on both sides from never being serviced/lubricated so they rusted to the point of no return,  also had some carbon buildup inside the butterfly opening at the point of full closure.

 

Try cleaning/lubricating the throttle plate spindle bearings on both sides. Don't try to replace the bearings unless you see damage, they will most likely be fused to the spindle from corrosion and you can damage the spindle trying to force them off. just passing on wisdom from my stupid mistakes.

 

A temporary fix add a return spring to the throttle linkage to force things closed.

[Triumph-V8]

You are right, maybe its nothing for the first try

but I changed bearings on dotzends of them and

never had incidents.

 

Maybe in that old times the old DCOEs there coming up had brass spindles that could not rust.

But those tend to distort and brake quickly. So not much better situation.

 

If spindle sticks in bearings I would refit the throttle plates to makes the whole

situation more stable and remove the securing pin from the accel plunger.

 

Than I would use heat and rustremover and a brass hammer and give it a try.....

Fully open the plates give a little way to loosen the bearing/spindle connection.

[aoie]

Good info to put the throttle plates back in to help prevent the spindle from crumpling like mine did.

 

Replacing the throttle  spindle new is a real pain, the securing pin hole for accel plunger needs to be drilled on the new replacement.

 

So add machinist cost to drill pin hole to match alignment of original spindle to the cost of the replacement part.

 

I learned never to make the same mistake again.

[Triumph-V8]

Drill the plunger hole with a dremel by hand with the plunger

and spindle in correct position.

When plates are fully closed the plunger must press the

pump a very little bit already.

Otherwise you get a little hickup when accelerating from idle.

[mattius]

Hmmm i connected back up the throttle external return springs and its solved my problem just now.

 

Its a bodge, but more pressing things to spend money on just now.

[mattius]

I had a problem with a bent throttle leaver so i got a chance to have a long look at it.

 

It was a strange one causing it i had never seen before, a lip on a poorly manufactured choke was just snagging the throttle plate. A quick spin on the lathe to remove the lip and now all functioning good.

 

Posted to help others, check the basics.