Choke

[Wagger]

5 hours ago, johny said:

I think you must be missing the basic problem as Ive got a rusty tank but havent had to resort to any alternatives to the original mechanical pump with a filter before it. If the inlet pipe did empty (which it doesnt even after months) then I could just refil it with the pumps manual lever👍  

If I connect my electric pump (that I use for draining tanks on all of my stuff) directly to the tank outlet, fuel arrives within a few seconds. However, if I connect the same pump to where the line appears under the bonnet, it takes over a minute. Pressurisinng it shows no leaks, so the pipe is restricted somewhere.

In my view, the best place for a filter is in the boot as I can see that without grovelling too much. Easy to change there too as I don't spill any fuel.

The glass bowl pump on the engine is very easy to inspect. It catches floaters and sinkers well.

I have now found a rubber join a third of the eay down, so that may be the culprit. Maybe it hates E10 fuel. PO's to blame again.

Having just got over ten weeks with sciatica, I do not fancy changing the pipe just yet. If I use it weekly, all is well, so must do that on a regular basis.

[johny]

yes sciatica, not nice! And yes if pumping with the electric in the engine bay and the fuel doesnt come through dirty or bubbly just slow it sounds, as you say, that theres something large in the fuel line....

[chrishawley]

On 26/07/2022 at 17:19, Pete Lewis said:

 

Indirectly related, but perhaps might give some ideas......

My Spit 1500 (on SU HS4s) has long been a good runner but difficult starter and from cold was dependent on a squirt of Easy Start to get going.

On close inspection yesterday I found: a) Choke cable not attched correctly restricting the range of movement, b) mechanismm acting unequally on the jets so that one carb was enriching well before the other, c) fast idle screws all wrong; imbalanced: one with no clearance from the cam, the other having masses.

Equalled everthing up and set a balanced fast idle. Today. Bingo! Starts on the first turn.

Obviously the arrangements on a CD150 are not the same as an HS4. But the general principle might apply of having a detailed look at the mechanism and adjustments. Possibly.

 

 

 

[Pete Lewis]

chokes on all our SU are a sytem of levers that drop the jet holder to richen the cold starts its important it returns fully when off choke 

a freindly poke witha finger to check the jet is up works .

on CDstrombergs  a CD has what i call the thames barrier which rises the air piston and needle and closes the throat to richen cold starts

CDS CDSE CDSEV   have a starting enrichment valve mounted on the side of the carb only on the front one the rear is fed by a short tube connecting the two

this has a disc inside with calibratedm holes to meter the enrichment on cold starts

all makes rely on the choke cable pulling all the offending method to the full extent of travel

all makes have a cam to speed up the fast idle  the srew on this must have a small gap and not touch the cam when the choke is Off

Idle screws are set to 1.5 turns in from being shut  and jets set equallly on each carb  statr at 3 turns down for a basic setting

CDSE with top adjusters is set the small delrin washer on the needle head level with the base of the air piston 

use a hex key down the dashpot  but do remove or hold the piston or you may tear the diaphragm 

theres not much else to do   on the side of CDSE can be temperature compensators  remove the cover and screw the nut to ensure the blasted things are fully closed ..for good 

if the plunger is bypassing the throttle you will never set the idle mixture .

Pete