Norman carb jetting

My T300 marine runs OK. I've promised to look before & now I'll actually try!

Regards,

Kim Siddorn

"Prepair Ltd" wrote

Unfortunately the full part No. (stamped on float bowl) is illegible due to corrosion, and may of course be incorrect anyway if it is a bitser, I'll have a look in the Norman parts list.

I haven't got all the Solex/Zenith carb sheets on the site yet, and if you can give me a Solex Part No I can check the master catalogues (2 at present) and see what we can find.

The main body of the data sheets is at:

Peter

-- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk

I also have the settings lists, but haven't had time to sort through them. It is quite possible that they will have the Norman settings.

Peter

-- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk

"Nick H" wrote

No good, only gives Norman part number (always a good wheeze to protect your spares market) 4424.

Thanks to both, I eagerly await the results of your various efforts!

"Nick H" wrote

From off-list contact Solex spec No. is LS 464077 - thanks John!

OK, I'll have a rummage tonight. Peter

-- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk

"Prepair Ltd" wrote

Thanks Peter. If no luck with that spec, you could also try L45 which John tells me is the No. on his MK1.

Only the T600 Industrial/Marine P/No 6112 ref S1473 1947-54 Type 26FHG

Then in the other books:

T300 MkII Industrial P/No 4424 1938-54 26FHG Ref S375 T300 Mk1 and MkII Marine S1396

No jet settings though, the booklets for the industrial stuff are missing in both sets as far as I can see.

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

"Peter A Forbes" wrote

B****r! But nil desperandum! John tells me he has unearthed a Norman workshop manual which gives the main jet as 70 x 58 leading to the perhaps not unexpected conclusion (given the handful of choke required) that my 50 x

58 main is too small enough!

Confusing news!!

The settings on my T300 marine - identical Solex 26FH, just not governed - are as follows. Main jet 90 and MC (dunno, perhaps it's a Scottish jet!) and the pilot is 55.

Of course, I was forced to start it up for five minutes to check that it was all OK.

Regards,

Kim Siddorn

"Nick H" wrote

Hmm. I would have expected it to be somewhat different since the marine engine is required to run cleanly over a wide speed range, whereas the stationary runs at substantially constant speed (though the Mk1 does have a slow-speed idle setting). But it seems a big step from a 70 to 90 (1/100 ths of a mm) main jet - the second figure relates to the correction holes in the side of the tube which effect the part throttle mixture, though according to the data on Peter F's site, it should be a number. OTOH the pilot jet is smaller! I believe the marine engine also has a restrictor between the carb and crankcase - presumably to limit no-load revs on this ungoverned version - which I guess also has some effect on carburation.

Restrictor? Dunno Nick, although it is a year or more since I had the carb off - but I don't recall one & it revs very cleanly.

Regards,

Kim Siddorn

"Nick H" wrote (snip)

What do you reckon my chances are of successfully opening up the main jet? After all, 0.7mm is not 'that' small.

Ah. Memory failing - but it does sound familiar now you say. There you go then, a restrictor ;o))

Regards,

Kim

After having checked float and jet height, I recently "re-jetted" a brass Solex 26MV carb with 18mm venturi, which had a main jet 90 (0.9mm) and auxilliary 40 (0.4mm) down to 60 (0.6mm) and 30 (0.3mm) by carefully soldering the jet orifice then creating a new aperture by using a micro-drill bit in a pin vice. I bought a set of micro-drills from eBay. Twenty sizes from 0.3mm to 1.6mm in 0.05mm graduations. I altered the auxilliary first, straight to 30 and no more stalling through sooty plugs at idle. Then started with the main jet at 0.5 mm. The engine would only run with choke, at 0.55mm half choke, and at

0.6mm just right. Open the throttle and no hesitation. Had the engine running at half load for forty minutes (one pint of petrol) and the plug was dark grey. I have since bought a Solex manual for M type carbs and the sizes are quite near to the theoretical sizes in the tables. The carb was from a larger capacity version of my own engine.

So give it a try, you can always reduce the size as I did. Good luck!

Regards, Dave Carter.

"Dave Carter" wrote > >

I have resolved to give it a go over easter!

We have a large selection of Carbide PCB drills down to some very small sizes. They're a bit fragile if using a hand-held drill, but if you need a particular size, give me a shout and I'll post one (after Easter now as we are home today for some building pre-sorting out with a LARGE skip")

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web: