Power loss

[vanisveryrusty]

Van has developed problem.
Goes along at 70mph then drops to 55.
Next day, not to be bad when cold, then couldnt get it above 30 when warm.
Suspecting auto choke stuck on ??
But only random guess as not driving it myself and haven't had chance to look at it.
Any ideas ?
1.9 petrol wc.

[Ralf85]

Could be the short earth wire that comes from the auto choke and connects to a nearby nut and bolt has come adrift? Check it out!

[vanisveryrusty]

Thanks Ralf, will do.

[kevtherev]

Van has developed problem.
Goes along at 70mph then drops to 55.
Next day, not to be bad when cold, then couldnt get it above 30 when warm.
Suspecting auto choke stuck on ??
But only random guess as not driving it myself and haven't had chance to look at it.
Any ideas ?
1.9 petrol wc.

The choke is only really "on" for 5-6 mins.
Best way to check is get the van warmed up and whip the duct off, you should see the flap wide open.
I would be considering the coil too
A poor coil will get hot..and then the spark gets weak and intermittent, causing power loss

[vanisveryrusty]

I thought about the coil, but at £70 for a replacement I didnt fancy trying it first.
Is there a way to check a coil with a meter or something ?
Rather than just feeling if its hot, which worked years ago on coils fitted to Morris Marinas, dont know if it applies here.

Can the choke get stuck in the "on" position ?
Which would cause a loss of power due to wrong mixture.............when the engine is warm .
Or is my logic flawed.

[kevtherev]

If you can borrow a good working coil it might allay any thoughts.
The choke can do a number of things.
it can flap about if the bimetal spring has busted.
it can stick if the spindle is siezed or stiff to move
it can flap about if the operating lever has come off/busted its plastic connector (carb off to see this)

want some pichers of it?

[vanisveryrusty]

Pictures would help.........if its not too much trouble.

Worrying thing is, tank has recently been dropped to replace seals and missing pipework to expansion tanks, so I think there may be a whole lot of crud working through the system just to make life interesting !

[kevtherev]

debris in the carb would certainly produce a weak mixture and power loss
and it wouldn't show up during engine warm up

pichers..
Looking up at the split carb
here you can see the spindle with all it's springs that operate the fast idle
on the extreme left is the emulsion tube and carb throat, the lever, is next to it or at least the bottom of it, on the right is the bimetal spring housing,



bottom of the lever here



and a close up



bi metal spring in it's housing



and the dog it connects to which turns the choke flap directly..well that is if the lever is ok

[vanisveryrusty]

Many thanks Kev.
Will post the result in a couple of days.

[Mocki]

Have you checked the filter?

[vanisveryrusty]

Not checked anything yet.
Daughter was using the van and it got relayed back in the dark
Filter under drivers door, and filter in the carb inside the fuel supply housing ?

Any other filters ?

[kevtherev]

That's about the lot
If it happened at speed the I suppose we ought to mention the pump, and it's ability to pump fuel.
worth checking that and the pushrod length. (100 mm)

[vanisveryrusty]

Yes it happened at speed initially.
Worth buying a replacement fuel pump from Baxter maybe ?
Can they be checked or is it just a replace if you think it may be suspect item ?

[kevtherev]

pull the inlet pipe off the carb and turn the engine over, you should get some healthy squirts of fuel
there is a spec, but I can't find it.
pushrods can be bought if yours is too short.

I've been thinking electric pump for a while now, Big herb posted up a great little pump, easily fitted.

[vanisveryrusty]

Thanks.
Why would it be too short if its been Ok up until now ?
Do they wear or something ?