On Wed, 17 Aug 2005 09:10:40 +0100 (BST), "Dave Liquorice"
wrote:

On Wed, 17 Aug 2005 07:57:23 +0100, Jupiter wrote:

You're describing the PulsaJet carb which is an older design.

This is no more than 3 years old. Can't a aresed to look for the full
engine number and work out the manufacture date.

Date of manufacture doesn't determine age of design!

A lot of newer engines have the PulsaPrime carb which has the big
rubber bulb to press 3 times for pre-starting priming. They don't
have that little diaphragm.

It has a press 3 times primer for cold engine start, it has a
diaphragm. It's not what I would call little, it also functions as a
gasket between the carb and tank from memory about 2 x 2.5".

Ah, so your diaphragm fits between the tank and carb, not under a
plate on the side of the carb. So yours is a PulsaPrime. The PulsaJet
has a 'little' diaphragm with 2 flap valves under a side plate and 2
dip tubes into the fuel tank. One draws from the bottom of the tank
and pumps into a secondary cup inside the tank and the engine is
supplied by the other one drawing from the cup so it doesn't need a
separate priming mechanism. The idea is that the cup is always full
so that the level of fuel in the main tank doesn't affect the
performance of the engine.

Still worth checking checking the filter screens on the dip tubes,
whatever the type. There's a lot of vibration with those engines and
any sediment will inevitably be stirred up.