Revs limited to 3500!

[Barrington_Tennant]

A friend brought me his newly acquired E-Type on the weekend because I know what an XK engine looks like! It is a 1969 US import to Germany with 2 x Stromberg Carbs & automatic box. A test drive on the Autobahn showed it to be a very pleasant car to drive except that it seems to rev limited to about 3500. Not missfiring, just will not go any faster! My first thought was not enough timing advance.
I checked the timing which seems to be about -10 TDC and stripped the distributor to clean the advance weights. Set the points (which seem not to be in top condition). Checked the carb. diaphragms. Tickover is a bit lumpy but I know that from my XK150.
I was surprised that there is no vacuum advance on the distributor.

Any thoughts as to what thge problem could be??

Best regards
Barry Tennant

[Marco (Mark)]

Is the throttle linkage limited in any way or preventing the carbs from being fully open ?

[Clive_Wilkinson]

Carpet too thick? It’s been known.

[Wiggles (Paul Wigton)]

As others have stated, ensure the throttles are fully opening, including the secondary throttles.

Then, do the “5-minute Strangleberg fix!”

1969 intake manifold throttle plates

John, The secondary throttle plates cause a proportion (a large proportion at low throttle settings, and progressively less at high throttle settings) of the air/fuel mixture to be diverted along the length of the secondary intake manifold and back, to preheat the mixture in an attempt to reduce emissions. Full details are contained in Section Q of your Service Manual. Removing them improves the responsiveness of the engine, and many of us have done so. How you do this depends on how much effo…

[Tudor95]

Will check. Thanks

Barry

[Michael_Frank]

Circumstances? At what speed were you going when you hit 3500? In what gear? What is the axle ratio?