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Throttle butterfly setting

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SHi, rebuilt my 150pi engine and purchased new throttle linkages as my old ones were badly worn. Got it all together and it's running like a pig. Is there anyone in the Lancashire area that can give me a hand. I have a couple of synchro gadgets and am aware of the theory of the job, but putting into practice is something quite different altogether. Thanks, Stephen 

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Don't despair it is not an easy task. I'm down Herefordshire, sorry too far away to assist. When you write running like a pig do you mean at low revs as you pull away?

Typically the butterfly adjustment in each pair and then the synchronising of the three pairs has its main effect as the car pull sways from standstill  up to perhaps 10 to 15 mph, after that the throttles are open wide'ish and all cylinders are breathing deeply the engine has reached a couple of thousand revs the plugs have cleared and any adjustment issues are not particularly discernible.

If the issues are more than that then butterfly adjustment may not be the only issue.


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Hi Stephen.

Are the linkage rods the aftermarket type? If so they are very hard to adjust and lock off. I can supply you with original spec linkage rods which will enable you to synchronise your butterflies properly without burning your hands on the hot exhaust manifold.
Kind regards

Martin (Fred Millturn Parts)

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Firstly make sure the butterflies are centred. Loosen the throttle cable and throttle stop so that you can fully close the butterflies.

Then loosen the two screws that hold the butterfly to each shaft. Open the butterflies by hand and allow to snap shut a couple of times and then nip the screws up. This centres the butterflies.

After that you can balance the throttles. Make sure the air bleed screw is fully closed when doing so.

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