HS2's flooding in turns

[ChrisS]

I have a set of SU HS2’s on my track car and I’m having a problem where the car will flood in tight turns. The fuel pressure is 1.5-2psi set by a bypass regulator. The carbs have the non-adjustable plastic floats. I have tried shimming the seat to lower the fuel level but it got to the point where the valve wouldn’t open (since the hinge point is fixed it starts to bind). So what am I missing? I’m going to try to locate a set of adjustable floats but I’m curious as to others thoughts. My solution yesterday was to shut off the fuel pump after just before the turns and then back on in the straights but that was a bit cumbersome – especially when I fat fingered the ignition switch also. This is cross posted in the racing forum.

 

[aeronca65t]

Hmmmm?
Be sure that the vents are open and make sure the needles aren't sticky.
You might try switching to Grose-Jets...they are supposed to be an improvement.
You're running very light (or no) oil in the carb dampers...right?
And...nice, strong spark?

 

[jlaird]

Admireing the problem I can only think like you that the fuel level is too high in the float chamber. Was there not a factory mod for correcting this. Sure I have seen something somewhere.

 

[ChrisS]

I put rebuild kit in it a few weeks ago to see if there was a needle valve problem. Replaced the needle (viton tipped) and seat, jet and gaskets. I didn't have a new set of floats but I've switched them with "know good" used ones with no change. Dampers have power steering fluid in them. Vents are good and clear.

 

[jlaird]

Call Joe. Bet he will have the solution. Shoot he is near you as well.

 

[ChrisS]

I talked to him this morning, it sounds like I need to find covers with different hinge to fuel port orientation to keep the floats from getting thrown open in the turns. Just curious to others thoughts / experience.

 

[jlaird]

Makes sence to me. But then what do I know.

 

[Tim Hollister]

I talked to him this morning, it sounds like I need to find covers with different hinge to fuel port orientation to keep the floats from getting thrown open in the turns. Just curious to others thoughts / experience.

Was going to suggest the orientation of the float bowl covers as I had a similar experience a couple of years back on my racing Midget. In my case, the rear carb was leaning out to the point that cylinders 3 & 4 were missing severely in right hand turns. It took a while before we figured out/remembered that I'd changed the orientation of the rear float bowl lid in an effort to reroute the fuel hose feed to that carb.

It was quite a frustrating weekend at the track (13 turns with 9 of those being right-handers) when the car would basically cut out on every right turn!

Once I reoriented that float bowl lid so that the hinge pin was straight across (left to right) the car, everything immediately returned to normal. As you report Joe told you, the lateral G forces were affecting the float's ability to function.

Tim

 

[JerryB]

ChrisS

I replied to your other post......look at that one.

 

[jlaird]

Yep, think I would just change em one turn. Same covers should work just fine.

 

[dklawson]

This is a common problem with racing Minis and the solution is frequently to rotate the float bowl covers 120 degrees (on HS2s). Are you not able to do this with Spridget HS2s? It might mean replacing metal fuel line with flex hose but I would think it would be quite possible to do.

 

[Aloysius]

HS2 carbs don't tend to rotate the lids very well. The rotate trick worked great with the H4 carbs on an MGA that had a banjo bolt on the top of the float chamber which allowed you to rotate at will.

I had a similar problem a few years ago, but in my case I was running out of fuel in long tight turns while autocrossing. At that time Joe C suggested rotation, too, but then, when I pointed out that HS2 carbs didn't do that well, he sold me a very expensive set of brass floats that are not attached to anything. At the top of the chamber you install a fork which activates the needle valve when the loose float pushes on it. I seem to recall that this was close to a $100 upgrade, but I have no complaints, since it eliminated the problem for me.

 

[Bugeye58]

But, there are float bowl covers available in several different float orientations.
Jeff

 

[Tim Hollister]

But, there a float bowl covers available in several different float orientations.
Jeff

As usual Jeff is right on. Having a bunch of carbs, thus float bowl covers, laying around, I simply looked through them and found one that solved both the orientation and fuel line routing problems.

Racers and people who like to tinker simply cannot have too many parts on hand! /bcforum/images/%%GRAEMLIN_URL%%/bow.gif

Tim

 

[ChrisS]

Thanks guys. I have some different covers and a friend is sending me all of his spares to select the right orientation. Between all the covers I should be able to find the right ones.