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MG TD TF 1500 - Grose Jets or Regular?

So I'm working on the carbs and have noticed that both the plastic needles seem to be a bit 'sticky' in the bowls. This may or may not be a problem when they are in place with the engine running (it idles well enough) but definitely, when I take the float bowl top off and turn them upside down and then back to see how the needles move, both of them will not drop, maybe 1 out of 3 times. I've done all the cleaning that is possible.

So I'm thinking I should get new needles.

So should I switch to grose jets or just go with the new viton ones?
Geoffrey M Baker

Must be using aftermarket kits. Needles in SU kits would be Viton tipped brass. I haven’t seen a lot lately re Grosse jets. But I seem to remember a lot of negative comments about them a few years ago. I’ve never used them so I have no opinion
W A Chasser

I've never changed the needles, these are probably 20 years old or older. For all I know they could be original :)

Geoffrey M Baker

Grosse jets were originally handmade by a small family business and were great
The business changed hands and there were several reports of dribbling jets not sealing off--From what I've heard the originals were all seated in and tested but the later ones were just assembled and that was it
The trick with the later ones is to give the needle(ball)a light tap into the seat with a small hammer just to set it into the seat and it will be fine, apparently the problem is that there is a sharp edge where the seat has been drilled and it just needs that tap with a hammer to shape the seat to suit the needle (ball)
William Revit

The issue is usually that there is water in the fuel which causes a film of deposit in the barrel of the needle seat - this is invisible while it is wet with fuel or cleaner.

Use a cotton bud or rolled up kitchen towel with a little Brasso to polish the inside of the barrel and it should solve the sticking issue.

Grose jets are OK when new but they also suffer the deposit issue and start leaking after a while, trouble if you cannot get inside them to clean them out.

NB Most fuel has a little water in it - either from the fuel station tanks or from condensation in the vehicle tank.
Chris at Octarine Services

I put Gross jets in my carbs and they leaked after a while, these were new! I'll never use them again, I installed the Viton jets and haven't had a problen since. PJ
PJ Jennings

Ill pick up a set of standard needles today.
Geoffrey M Baker

OK< replaced the carb bowl needles with new viton tipped ones, then added damper oil to the dashpots.

Big difference! Now she revs without hesitation and holds the speed well.

Next: on to timing the engine and syncing the carbs. Still low idle is a very up and down business, doesnt quit but not steady, just a cycling up and down at the low end.

Geoffrey M Baker

This thread was discussed between 28/11/2019 and 05/12/2019

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