TR4/4A Tr4a, Stromberg float setting

[Rrbbeerrttoo]

This episode begun with fuel smell in the garage , but had found no leaks anywhere, believe me.
So I rebuilt the carb, diaphram, seals, fuel fill valve functioned ok, did not touch the float level although the setting distance was about 7/8, not of 3/4 ( .73 in.)as manual says. After a long run (60-70 mph ), I stopped ,smelled gas , inspected carb and found some fuel inside, on air intake, by the jet bridge. An earlier shorter run , 40-50 mph, did not smell gas, nor was there fuel by the jet bridge.

Question 1. If I now set float valve correctly to 3/4, does it not mean that a fuller fuel reservoir could make conditions worse, with more fuel in the reservoir?.
Question 2, How full should the reservoir be (3/8,1/2, 3/4 )when the the float shuts off fuel?

Thanks for any comments.

Robert
66' tr4a irs
CTC 53788 L

 

[glemon]

I believe you are sort or right, making the float measure shorter would raise the fuel level, however, if it is overflowing I would guess you have another problem, either with the valve (I know you checked, but the fault can be intermittent) dirt or debris in the valve, or possibly with the float, I think the float for these may be a solid rather than hollow, and may deteriorate and absorb gas? I am not sure if they are hollow or solid, I know they are usually a dark black gray color, and they don't seem to be like a modern poly/plastic.

In my experience small variations in float height don't make much difference in operating characteristics or leakage. Best to set it as per manual but an eight of an inch either way probably won't cause (or cure) any signigicant problems.

 

[DanB]

Are you sure your floats are floating?

 

[Rrbbeerrttoo]

DanB/Glemon
Thanks for the comments. A few more details of my investigation:

1. Before removing carb, I disconnected fuel line and attempted to slowly blow air thru its pipe connection. No air went thru ( valve close ). Then, while slowly uncrewing reservoir bottom adjustment, allowing fuel to leak out, I was then able to blow air thru( valve opened ). No, did not measure fuel leaked out.
2. After removing carb, while still assembled, and with screw adjustments removed, I tilted carb back and forth and could hear float moving...also blew air again with float moving up ( no air thru ) and down ( air went thru ), indicating valve still working.
3. Opened reservoir and inspected float movement. It functioned fine. I tilted carb and watched valve ball open and closed with gravity. Yes, I blew air again and functioned fine.
4. Could not tell definitely if float was hollow or solid plastic. My guess is hollow as it weighed 5/8 oz. Its color is black gray.
5. Finally, removed and soaked float in fuel for two hours. After soaking it still weighed 5/8oz .

It is time to set float by the manual, although it will actuate valve at higher fuel level than I found it.

Robert
66' tr4a irs
CTC 53788 L

 

[poolboy]

Ball Valve, you said ?
If it's the Grose Jet which has a ball, that alone may be the problem. I tried them and gave up because they would not reliably shut off the fuel when the floats rose.
Grose Jet on Right.

 

[DanB]

I gave up on the Grose Jets too, and put the old valves back in. But I finally gave up on the carbs and put EFI on too....

 

[Rrbbeerrttoo]

Thank you gentlemen,
Although the problem is with only one carb, I'll substitute one Gros Jet with the alternative . However, having become such speedy assembly expert removing, installing and adjusting carbs, I will give Gros jet one more chance.. while waiting for my next Moss purchase ( or H&S will be higher than the valve cost ).
As usual, your comments were invaluable.

Robert
tr4a irs
CTC 53788 L