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Quick question on setting fast idle/balancing carb

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livinginthepast

livinginthepast

Jedi Trainee
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Hey there,

I'm still tweaking, trying to get the carbs set up just right - H1s on 60 BE.

I'm curious how you all set the fast idle. I'm getting pretty damned proficient in quickly balancing the carbs, still struggling with the mixture (not sure why I have to back off the mixture nuts so far to get a decent mix - but maybe I'm not interpreting the manual correctly).

So the fast idle screw, as those who have been following my education in carbs, has been giving me trouble. The issue with holding the screw in place was in fact the spring. But I have a more pressing question. What is the correct procedure for setting up the front carbs two idle adjustments? I've just been playing it by ear - as my manual really doesn't say anything about it.

Oh, one other thing with the needles. I had to tweak the needle position (recessed into the piston body slightly), but I was wondering how these needles are intended to be positioned. These are standard GG needles (moss 374-095). I started by positioning them flush with the bottom of the piston. Shouuld I have pushed them all the way in to the piston?

Thanks!
 
SU Needles should be flush with the bottom of the piston. That you have them slightly recessed indicates that your jet is possibly too high? Though that doesn't quite gell with your writing about backing off the nuts so much, I must say.
The purpose of the nuts is to adjust the height of the jet, and hence the mixture strength. When you back them off, you lower the jet, if I interpret you right. Are you sure the jet is descending when you do that? Sometimes the choke (rich mixture adjustment for starting) mechanism can foul up the adjustment of the jet height if it's too "tight".

You should set the mixture with the engine warmed up and the choke completely slackened off, and the car running at a fast idle. Then back off the slow-running screws so you achieve the normal idle you want.

Then you can tighten up the choke mechanism, making sure it doesn't affect your idle setting - the fast idle screw should be backed off.
With the engine stopped, pull the choke and adjust the fast idle screw so it's just opening the throttles a bit. You may have to play with it a bit to get it how you want it.
 
Hi Roger,

Thanks for this.

I suspect there are other, undiagnosed issues that need addressing. I'm getting inconsistent results, there's some stumbling on acceleration that I can't tune out, the mixture seems to need constant attention (just when I think it's about right, I check it again and it's lean, etc.)

I think I'm just going to drive it for now while there's some summer left and then ask for more experienced help in the fall :smile: I had hoped to master this particular skill (SU adjustment) this summer, but it doesn't look like its going to happen!

Thanks again for your help!

BillW
 
Bill, try tightening everything up that could let in air - manifold, carbs etc. sounds like a vacuum issue
 
Bill, "read" your spark plugs: what do you see??

Lots of carbon fouling? Ideally there should be some carbon deposits, but not excessive.

What do they look like?
 
Don't let the termonology mess with you, fast idle screws do one thing and one thing only, set the idle speed of the choke, if you didn't use the choke, they don't even have to be there.
 
vagt6 said:
Bill, "read" your spark plugs: what do you see??

Lots of carbon fouling? Ideally there should be some carbon deposits, but not excessive.

What do they look like?
Click to expand...

The plugs seem to indicate that I'm running lean, although these are brand new plugs and there are only about 5 miles on them, so I'm not sure how revealing the very light white deposits are going to be. Cyl 3 tells me I have some other issue (wet/oily fouling - I've got 156 compression in that cylinder, so I'm not sure what's happening there).

Thanks!
 
JPSmit said:
Bill, try tightening everything up that could let in air - manifold, carbs etc. sounds like a vacuum issue
Click to expand...

I need to check all this again. On Saturday I tightened down the carbs to manifold, but I did not check the bolts on the intake manifold. Now, I thought that I could spray down the manifold to head mating points to check for leaks, but someone told me that's not going to tell me much...so I don't know if that was a waste of time or not.

Then, while looking at the manual again, I read that the carbs don't need to be tightened much more than the torque it takes to flatten the lock washers, and that too tight risks distorting mating surfaces...so I went back and loosened a little.

Yeah, it's been a little nuts.
 
Hap Waldrop said:
Don't let the termonology mess with you, fast idle screws do one thing and one thing only, set the idle speed of the choke, if you didn't use the choke, they don't even have to be there.
Click to expand...

Thank you, that's one of the overarching questions I had.
BillW
 
livinginthepast said:
Hap Waldrop said:
Don't let the termonology mess with you, fast idle screws do one thing and one thing only, set the idle speed of the choke, if you didn't use the choke, they don't even have to be there.
Click to expand...

Thank you, that's one of the overarching questions I had.
BillW
Click to expand...

Yes, that's what I meant to indicate. Guess I didn't do it well enough!
 
Stumbling on acceleration can also be caused by too thin or not enough oil in the carb dash pots causing a lean condition.
 
Re: Quick question on setting fast idle/balancing

Bayless said:
Stumbling on acceleration can also be caused by too thin or not enough oil in the carb dash pots causing a lean condition.
Click to expand...
:iagree: I had marvel mystery oil in and it was too thin - things improved with engine oil
 
Re: Quick question on setting fast idle/balancing

JPSmit said:
Bayless said:
Stumbling on acceleration can also be caused by too thin or not enough oil in the carb dash pots causing a lean condition.
Click to expand...
:iagree: I had marvel mystery oil in and it was too thin - things improved with engine oil
Click to expand...

I'm using ATF. I'll change to engine oil and see if that makes a diff. Thanks!
 
Re: Quick question on setting fast idle/balancing

The good news is that the BE finally seems to be running well (well, as good as possible considering all the miles :smile:

It just took some patient tweaking. I did tighten up the intake manifold and then managed to smooth out the idle by turning out the mixture a little more on the rear carb. It now accelerates smoothly and idles at a reasonable speed. It's certainly not perfect, and I'm not convinced that I *should* have to turn out the mixture nuts as far as I had to, but I'm not going to complain - it's running good and there's plenty of summer (and fall) left.

Thanks everyone for your input. I've learned a lot these past few weeks.
 
Re: Quick question on setting fast idle/balancing

Hey Bill, at least it's not dumping gas like mine.
BillM & I tried to work on them, I ended up nursing the car back home.

Taking his advice I've removed the HS2's from my parts car, pulled the intake manifolds and am ready to swap.

It's amazing how much larger HS2's are than H1's... At first I thought I could just unbolt the carbs and swap them over... No way.

I took a wire wheel to the "new" heat shield, then painted with anti-rust then with high temp black. I'll be ready to assemble tomorrow - weather permitting!!
 
Re: Quick question on setting fast idle/balancing

Rick, not only larger, but nicer to fiddle with too IMHO! :wink:
 
Re: Quick question on setting fast idle/balancing

RickB said:
...It's amazing how much larger HS2's are than H1's... At first I thought I could just unbolt the carbs and swap them over... No way.

I took a wire wheel to the "new" heat shield, then painted with anti-rust then with high temp black. I'll be ready to assemble tomorrow - weather permitting!!
Click to expand...

Good luck with the swap! Keep me informed. Once all the cars are reasonably dependable, all us spridget drivin' local yokels should go for a drive... but not too far away from the tools - ha! :smile:
 
Re: Quick question on setting fast idle/balancing

livinginthepast said:
RickB said:
...It's amazing how much larger HS2's are than H1's... At first I thought I could just unbolt the carbs and swap them over... No way.

I took a wire wheel to the "new" heat shield, then painted with anti-rust then with high temp black. I'll be ready to assemble tomorrow - weather permitting!!
Click to expand...

Good luck with the swap! Keep me informed. Once all the cars are reasonably dependable, all us spridget drivin' local yokels should go for a drive... but not too far away from the tools - ha! :smile:
Click to expand...

WHAAAAAAT!!! You don't carry tools WITH you??? :jester:
 
Re: Quick question on setting fast idle/balancing

What I found that I was most impressed by was how clean the old carbs were (inside).
They were from my MK1 Midget parts car, it had the original air cleaners on with intact filters so nothing could get inside for all the time it's sat (at least 20 years).

The pistons move freely, the chokes operate smoothly, the insides are pristine.
On the outside they are dirty & ugly, but inside like brand new.
The paint on the heat shield is dry so when I get home tonight I should be able to bolt the HS2's on and see if they work.

I'm stopping by the store to get some blue Permatex, an inline fuel filter and some new spark plugs. Hopefully tonight the little red one will be back in business. :wink:
 
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