MGB SU HS4 jet height adjustments

[torque-drive]

I read somewhere that the top of your jet should be flush with the bridge. Is this true, and if so, is this causing any major running issues?

 

[Mickey Richaud]

Mornin'!

Level with the bridge is a starting point. from there, adjust the jet bearing down 12 flats (of the hex adjusting nut), and proceed to fine tune from there.

Here ya go: https://www.mgexp.com/phile/1/641497/Emissions_Manual_-_4C-comp.pdf

 

[Tim Hollister]

Unfortunately Mickey, your link goes to the procedure for HS2 carbs. The OP was asking about HS4 carbs.

And now that I've purchased my first MGB (a 1973) I find myself in the boat as the OP.

Tim Hollister
Trout Lake, MI

 

[BobHaskell]

Unfortunately Mickey, your link goes to the procedure for HS2 carbs. The OP was asking about HS4 carbs.

And now that I've purchased my first MGB (a 1973) I find myself in the boat as the OP.

Tim Hollister
Trout Lake, MI

The procedure for tuning HS4 carbs is the same as HS2.

 

[Tim Hollister]

Unfortunately due to the mechanical design differences, the physical procedure is NOT the same -- especially for someone who is very familiar with the HS2 and HS4 carbs but has never seen an HIF4 carb.

I do understand and concede the theory is the same however I have yet to find a place to use a wrench on the HIF4 carb to adjust the mixture.

Lastly, I now have rebuild kits on hand from British Parts Northwest for my HIF4's on my 73 MGB and will enjoy rebuilding, installing, and yes, adjusting these carbs so my car runs right. You see, the rear carb was running very rich and would not respond to adjustments while the front carb is fine and responds as predicted. (yes, I'll make certain the float in the rear carb really floats...)

Bob, thanks for your attempt at helping me.

Tim Hollister
Trout Lake, MI (out in the boonies of Michigan's eastern upper peninsula)

 

[DrEntropy]

First mention the SU's in question are H-I-F4's:

Unfortunately Mickey, your link goes to the procedure for HS2 carbs. The OP was asking about HS4 carbs.

Have a look at this video for a good procedure.

Specifics matter.

 

[Tim Hollister]

Thanks for setting me straight, Dr Entropy. I just thoroughly reviewed this thread and see the original misunderstanding was mine. The OP was in fact referring to HS4 carbs, not HIF4 carbs as I thought. My apologies to the group.

And thanks for the link to EndFloat's excellent HIF4 rebuild video. I had already found it and intend to use it on my iPad out in the garage over the next day or two as I rebuild my HIF4s.

Thanks again!!