[Healeys] HS4 Tri-carb tuning

[Perry]

Dave Porter is on the money.  Start back at the beginning of the adjustment procedure and tune the jet nuts to get the highest RPM on each carb, turn the idle screws back to get the right idle speed, then try lifting the pins.  Just because things look like the old setup does not mean they are. If the jets have not been centered it can throw everything off.  If lifting the pin all the way does not stall or at least slow the idle noticeably, then the carb is usually to rich. Oh and by the way, after you lift those pins 500 or so times you can hear the results without measuring 1/32 or an inch. 
P

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From: John Spaur via Healeys
Sent: Tuesday, July 7, 2020 1:03 AM
To: healeys at autox.team.net
Subject: Re: [Healeys] HS4 Tri-carb tuning

I might have a Colortune but I don’t know where. However, I don’t think a CT will help answer my question. I want to know if other Healey owners, with three S.U carbs (HS4’s) or even two, know if lifting the piston 1/4”will stall the engine when independently tested on each carb.


From: Healeys [mailto:healeys-bounces at autox.team.net] On Behalf Of Bob Spidell
Sent: Monday, July 6, 2020 8:36 PM
To: healeys at autox.team.net
Subject: Re: [Healeys] HS4 Tri-carb tuning

Do you have a Colortune?
On 7/6/2020 7:07 PM, John Spaur via Healeys wrote:
Bob, raising the piston 1/32” is not my issue. I am wondering why the engine stalls when the center carb piston is lifted all the way up and the others don’t stall the engine when lifted all the way up. I sent another post with a link for that. The carbs are well synced, I used the S.U tuning kit to check the piston lift and they are spot on.
 
From: Healeys [mailto:healeys-bounces at autox.team.net] On Behalf Of Bob Spidell
Sent: Monday, July 6, 2020 6:32 PM
To: healeys at autox.team.net
Subject: Re: [Healeys] HS4 Tri-carb tuning
 
After much effort and consideration, I decided there must be some Brits who wrote that 'procedure' laughing their asses off knowing there is no practical* way to lift the pistons exactly 1/32"

* But you can, if you have the little wire thingies in the poor man's tuning kit--actually quite useful--stick the wire thingies in the piston and gauge the piston rise; the wires themselves are pretty close to 1/32" thick
On 7/6/2020 3:39 PM, John Spaur via Healeys wrote:
I installed three brand new HS4 carbs on my BT7 this weekend. They seem to work really well with no load and light load on some very short test drives. The jet adjusting nuts are very close to what the old ones were set to. One of the tests is to lift the piston with the lifting pin as far as you can. That is supposed to stall the engine. However, this only works on the center carb. When I test the front and rear, it just slows the engine down a bit. What have others found when they do this test? BTW, I can hardly tell a difference in the engine speed when I lift the pistons 1/32”.
 
TIA,
 
John
San Jose, CA 
 
 



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