[Mgs] H4 or HS4 carbs on an MGA 1600 and Electronic Ignition

Eric Russell ejrussell at mebtel.net
Tue Jan 9 14:54:46 MST 2018

I can't imagine any significant power difference between H4 & HS4 carbs. 
The throats are the same. I suspect the HS4 carbs will be a little less 
leak-prone. (the rubber grommets on the H4 float bowl tend to be a weak 
point, IME) I don't think HS4's came with the decel valve in the 
throttle plate - if they did that could be a small difference in power.

I am not a fan of replacement electronic ignition systems. When they 
work they work just fine. But when they don't work, replacement of the 
entire unit seems like the only option. With points, an occasional 
tune-up keeps it working fine. And if something does go wrong when 
you're on the road, a tiny kit with spare points & condensor is almost 
surely all you'd need to get going again.

Eric Russell
Mebane, NC
> Date: Tue, 9 Jan 2018 10:52:13 -0600
> From: "Robert J. Guinness" <guinness at stclegal.com>
> To: mgs at autox.team.net
> Subject: [Mgs] H4 or HS4 carbs on an MGA 1600 and Electronic Ignition
> I bought an MGA 1600 with HS4 carbs conversion and a crane fireball
> electronic ignition.? I would like to go back to a stock set up.? What
> are the *significant* pros and cons for doing so, for example power
> (rather than ease of maintenance)?? I know the H4s, but I am unfamiliar
> with working with HS4s (same with points vs electronic ignition).

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