What have i done?

[tangocharlie1]

Just finished fitting the club alloy mounts to my sprint, put it all back together and started it up today, but the car immediately races up to 4000rpm so I had to quickly turn it off, cannot see anything obvious. Have I put the linkages back together properly ?
What would cause this ? I have enclosed some pictures of the current state of the linkages they look correct to me. Have I missed something obvious?





I did spray some start x into the carbs before refitting the air filter as the car has not been started for a while but assume that is unrelated.

[Jon Tilson]

Your choke linkage is holding the fast idle on on the left carburetter

Release the clamps on your choke linkage and get them so that at rest - choke off - they don't tough the fast idle screw at all.

Jonners

[Toledo Man]

I'd got back to basics and set everything up again from scratch. Your new carb mounts will have knocked all your settings out of kilter so you'll need to do them all over again. Before you do anything, unscrew your idle screws so that the throttle is fully closed. If you're not sure how to set up your carbs take a look at Jonners' SU tuning guide on the Dolly Wiki.

[MIG Wielder]

slant throttle lever.jpg (60.77 KiB) Viewed 1180 times

There are 2 things I would look at.
The first one is the throttle lever linkage with the nylon roller. Before now I have got it back on the wrong side.
This is what it should look like at idle.
If that is O.K. I'd have the air filter element out and look down the barrels at the brass throttle disc. One or other may not be closing properly maybe because the gasket has slipped downwards during fitting and is stopping the throttle disc closing completely.
Either way operating the linkage by hand while looking at the throttle discs, should give an idea of where the problem lies.
Tony.

[tangocharlie1]

Thanks tony for that, i think i would discount the throttle leaver as i did not remove this when fitting the mounts, but i did fit gaskets that is something i will look at, im away this week so cannot get to the car until the weekend before i start playing with it.

[Robert 352]

On fitting a pair of the alloy mounts I too had exactly the same outcome as tangocharlie1 (TJ1) did here in that on starting the engine in my car the revs went above 3000rpm.

I studied the photos and looked at my car and read all the suggestions made above and it was only when I loosened all the nuts on the throttle connecting/actuating arm did I spot what was wrong. Hopefully TJ1 has already solved the problem but for those of you who might be faced with a similar problem I have marked on TJ1’s photo what the problem was.

DSCF2428P throttle linkage.jpg (191.72 KiB) Viewed 1015 times

If you look at the two arrows on the photo you will see that under the right hand arrow the fork is holding the butterfly spindle clear of the idle screw and it is this which is causing the engine to race. By slackening the nut pointed to by the left hand arrow the right hand spring passing under the two arrows will close the butterfly spindle and the revs will drop back to be controlled by the idle screw adjustment.

I would question though whether gaskets were necessary for the o-rings act as the seals between the alloy mounts, the inlet manifold and the carb bodies.

Robert

[tangocharlie1]

Thanks for posting that Robert, you are of course correct and with the help of Jon Tilson's excellent advice I followed his instructions and loosened and re-adjusted the clamps and this indeed brought down the revs, I think it is important that you have highlighted this now to help others. I am wondering if this only effects early sprints as I have noticed the later cars seem to have a different set up using only one centralized spring and I know owners of later cars that have done this conversion without issue.
You are also correct about the gaskets I have since removed mine as I felt they may well be fouling the throttle spindle.