Tillotson carb

[barrie burton]

I have a 3w 75,with a Tillotson carb.Tick- over is great,full power good,pick up from tick- over to full power is good,but very time I taxi from the pits,at about 1/4 throttle,the engine burbles and stops after about 5 minutes,or less, running.It will run a full tank through on tick over or full throttle.Any ideas,please.

Barrie B

[Ken Roddham]

Barrie - a couple of things to check with the Tillotson HS carb
1. In the atmos.chamber end of the carb check that the centre stud of the diaphragm is hooked onto the inlet control lever, and not resting on top.
2. Check that the height of the needle control lever is correct i.e. flush with the top of the recess
3. Check that the inlet tension spring is in place and not missing or dislodged to one side.
4. Ensure diaphragms are soft and flexible and not getting old and stiff.
Hope this helps, Ken

[barrie burton]

Thanks Ken,the engine is some years old,but it is un-run,the diaphrams may have hardened,although if this is the case,why does it run a full tank through on the ground?

Barrie B

[Ken Roddham]

Barrie - When the engine is running from idle through intermediate, to high speed the fuel from the carb is provided from three different ports - initially the primary port, then the primary and secondary ports, and finally primary, secondary and high speed ports. All the time accurate metering is provided by the main diaphragm.
Because of the age of the engine, and initially the un-run dry carb I think that possibly a gasket and diaphragm replacement would solve the problem.
Diaphragm replacement wouldn't do any harm and at the same time the carb could be cleaned.
Ken

[Peter Siggins]

Hi Barry ,

For a prompt service for Tillotson carbs try Rowena Motors of Bangor N.Wales,they operate avast range of carb spares for Tillotson and Walbro.

All the best

Pete

[barrie burton]

Problem now sorted,I hope,a new carb kit seems to have solved problem.Many thanks for your help.

Barrie B