I have a 4.2 Jaguar XK engine on triple 45 dcoe type 151 Webers.

Presently running like a dog, smelling of petrol and the fuel pump doesn't stop, I'm planning on replacing the fuel lines pump and regulator, I have all new parts left over from a previous project.

But, I'm told I need Type 9 webers, not 151's, can anyone enlighten me as to the difference?

Cheers.

Shouldn't make a difference at all as to which model of carb you have, choke size is quite important but correctly jetted and tuned carbs should work no matter the make model, i.e. although a 38 works on a pinto so will anything from 36-50! Also you could use dcoe's or idf's or a single carb!

maybe phone up here - linky they also list a triple carb kit for the jag so will no doubt know what it should have and probably tell you what may be up with it.

Saying that if the pumps not stopping and your smelling fuel, I'd suspect one of the carbs has a float chamber valve not shutting off and you'd need to check that quite pronto before it sets fire to your engine.

It sounds like either a float level or fuel pressure problem.
Before you buy a regulator

The first thing I would do is whip the tops of the carbs and check the float levels as per Weber manual.

Also a good idea to remove and clean the jets and when you replace them check they are screwed in tightly enough.

The fuel pressure should be easy enough to check I use a gauges I bought from this seller earlier in the year for about a tenner.
http://stores.shop.ebay.co.uk/Maziak-Compressors-And-Supplies_Fuel-Gauges-Fittings_W0QQ_fsubZ766003013QQ_sidZ79366173QQ_trksidZp4634Q2ec0Q2em322

Thanks chaps, there is no petrol visibly leaking, so I'm suspecting the pump valves or diaphragm have split enough to allow the smell through, and if I seal the fuel line using a brake line clamp it makes no difference.

Will whip the tops off later and check the floats.

can you turn the pump on with the engine off? if so then if it was a float valve not sealing it wouldn't take long to spot it dripping.

My allegro (twin SU carbs) so called sports model had this happen and the whole engine bay was drenched with fuel, what’s worse was the line of fuel on the ground all the way behind the car

Perhaps ask the person that told you you need type 9s why ( I know some carbs were specific to some cars and dont work well on others holbay hunter carbs had special progression holes for instance)
if the pump is electric and doesnt slow down or stop when you block the flow then it does sound like the diaphragm has a leak
Ray

DCOEs don't have any diaphragm in them, what can happen is the cold start plunger valves at the rear of the carb can get stuck in the up position.

Its the diaphragm in the electric pump I was on about, it cant be creating much pressure if I can crimp the fuel pipe and it keep 'pumping' or at least making its pumping noise.

Not venturing into the garage tonight, it can wait.

Cheers.
Pete.

Check out this ebay auction; they describe the difference between type 9s and 151/152s

Linky