Help! SU H2 Carburetor Float Level Setting?

[martyc]

Hello! I'm in the middle (well not quite the middle, really) of rebuilding the carbs on the TD and I can not find an important piece of information!

Can anyone tell me the proper setting for float height for the 1 1/4" H2 carbs? I've looked in the MG Workshop Manual, the TD Operation Manual, and I've searched online...all to no avail.

By float level, I mean the distance between the hinged lever and the float bowl lid face when the needle valve is closed. I've got the SU toolkit for setting it up properly...I just need the proper specification.

Thanks!
Marty

 

[John Moore]

Marty,

This is from the Haynes Techbook Manual on SU Carbs. Type H Carbs.

"Fit the float chamber valve seating to the float chamber lid. Fit the needle, hinged lever and hinge pin. With the hinged lever resting on the seated needle, check that a 0.44 in (11mm) diamter twist drill can be inserted between the forked lever and lip of the float chamber lid. If there is a gap, or if the bar lifts the forked lever clear of the needle, adjust by bending the lever where shown (fig.5.6)"

Hope that helps!

 

[martyc]

John,

Thanks! 0.44" is closest to the 7/16" measuring tool provided in the SU toolkit (kit has 3/8, 7/16 and 5/16). So I'll use that one.

Thanks a lot for your quick reply...I can get back to work on the carbs!

Best regards,
Marty

 

[Banjo]

Bingo! I've always used a 7/16ths drill. Quick, easy,works like a charm, and its cheap. You can play with the levels a little, until you get it where you like, but the 7/16ths seems to put it spot on.
The biggest thing is to make sure the front and rear carbs are set the same. If the float levels are different you'll be twisting the other adjustment screws all day and wondering why the carbs won't sync.

 

[tmp]

page B.11 in the MG TD workshop manual. bottom right corner of the page. tom

 

[martyc]

I've got a different workshop manual, I believe..."The M.G. Workshop Manual from M Type to TF 1500" by W.E. Blower Copyright 1970, Revised 1975.

It says "Complete Tuning and Maintenance for All Models from "M" Type to "T.F. 1500". It seems to cover most things, but no float level settings (and no page B.11).

Is the manual you mention better than the one I've got?

Marty

 

[Deleted member 3577]

Regardless of what you use as a starting point for the adjustment, double check by running the fuel pump, with the needle and suction chamber removed, to determine the ACTUAL level of fuel inside the jet. This can more readily be accomplished if the choke is pulled out to lower the jets until you just see the fuel.
I tried to adjust the fuel level by just using the rod under the fork method and the fuel level was off between the two carbs.
It is up to you how far below the top you want your fuel. For performance it is good to get it as high as possible without it bouncing out into the throat. I have mine set 1/8" down on each.
I finally figured all this out on my own after MANY hours of fiddling and trying to determine why the engine was running rough at tick over (idle).
(Both forks were set equal and the fuel levels were way off)

 

[tmp]

marty i would stongly recommend the MG workshop manual. readily available from ebay, most auto literature stores (walter miller, or books4cars, etc.)or used book search engines. the horst schach MG TD restoration manual is useful as well. if you don't have an illustrated parts book yet i would suggest that as well, same sources listed above. best of luck. tom