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Well my Midget made it home... Need Help!
- Thread starter RickB
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RickB
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Re: Well my Midget made it home...
The carbs started out running VERY rich, putting out much smoke from the exhaust.
BillM started tuning them, they didn't want to respond to this very much.
After a few attempts we sat and thought about it, and I remembered the Facet fuel pump I installed for the Datsun carb had 4 to 6 pounds pressure, too much cor the SU's.
Bill quickly located a low pressure fuel pump and I installed it.
Things got better momentarily, but then started going bad again.
We put in a little gas from Bill's can and it still wouldn't run.
Quickly swapping in another fuel pump and the thing started again, but back to smoking.
The rear carb was over boarding, too much fuel going through it.
Bill tried adjusting and got it to about where I could maybe drive it and I took off.
Within several hundred yards I had to pull off, it was running so badly that I just couldn't go. I called Bill and he said to try richening both carbs, so I did that and it would take off again so I started out.
I barely made it to the nearest gas station and fueled up.
Between there and the freeway it was just running badly, but running.
I got on, driving in the far right lane with my flashers on.
I got off at High Point Way, about a mile, where there was a road I could take all the way home so I wouldn't be on the freeway.
The carbs changed to racing away, running roughly but high rpm.
I managed to shift between 3rd & 4th most of the way and after quite a while made it home.
So - now what to do?
I have only ever had the HS series carbs before, this type SU is new to me.
It may be that they are simply not usable as is. I really don't know.
I plan on going out today and trying to adjust them and see if I can get it to running.
Any pointers at all, things to look for, what to do next advice GREATLY appreciated.
The carbs started out running VERY rich, putting out much smoke from the exhaust.
BillM started tuning them, they didn't want to respond to this very much.
After a few attempts we sat and thought about it, and I remembered the Facet fuel pump I installed for the Datsun carb had 4 to 6 pounds pressure, too much cor the SU's.
Bill quickly located a low pressure fuel pump and I installed it.
Things got better momentarily, but then started going bad again.
We put in a little gas from Bill's can and it still wouldn't run.
Quickly swapping in another fuel pump and the thing started again, but back to smoking.
The rear carb was over boarding, too much fuel going through it.
Bill tried adjusting and got it to about where I could maybe drive it and I took off.
Within several hundred yards I had to pull off, it was running so badly that I just couldn't go. I called Bill and he said to try richening both carbs, so I did that and it would take off again so I started out.
I barely made it to the nearest gas station and fueled up.
Between there and the freeway it was just running badly, but running.
I got on, driving in the far right lane with my flashers on.
I got off at High Point Way, about a mile, where there was a road I could take all the way home so I wouldn't be on the freeway.
The carbs changed to racing away, running roughly but high rpm.
I managed to shift between 3rd & 4th most of the way and after quite a while made it home.
So - now what to do?
I have only ever had the HS series carbs before, this type SU is new to me.
It may be that they are simply not usable as is. I really don't know.
I plan on going out today and trying to adjust them and see if I can get it to running.
Any pointers at all, things to look for, what to do next advice GREATLY appreciated.
Trevor Jessie
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Re: Well my Midget made it home...
What type of manifold design?
What type of manifold design?
Trevor Jessie
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Re: Well my Midget made it home...
So the carb mounts level?
So the carb mounts level?
SilentUnicorn
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Re: Well my Midget made it home...
you need air filters. Su's like a little restriction- I believe it helps with the pressure differential thing. I tried running like that with just rams. Didn't work as well as when i put some filter material over the rams. Of course the gas pouring out doesn't help. Sounds like you need to make sure your floats are not stuck. and the float height is set correctly.
m
you need air filters. Su's like a little restriction- I believe it helps with the pressure differential thing. I tried running like that with just rams. Didn't work as well as when i put some filter material over the rams. Of course the gas pouring out doesn't help. Sounds like you need to make sure your floats are not stuck. and the float height is set correctly.
m
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RickB
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Re: Well my Midget made it home...
Notice there is a fuel feed hose that loops around to the back carb?
I'm looking and looking and looking and not seeing it until just now, the things have a hose that goes between the two carbs at the front, supposedly to feed fuel from the front to the back carb.
So why does this fuel line from the pump go to both carbs I was wondering?
I look and look at the diagram in the book and it just hits me - there's a fuel feed hose to the front carb but the back only has "breather pipe" and "vent hose" connections on the right side - no fuel feed in over there as the fuel feed in is on the left side of that carb!!
So - what happens when you feed fuel into the carb via the 'vent tube' or the 'breather pipe'?
Whatever it is, I will bet it isn't good!!!
Going out to make it look like the book right now. Will report soon.
Notice there is a fuel feed hose that loops around to the back carb?
I'm looking and looking and looking and not seeing it until just now, the things have a hose that goes between the two carbs at the front, supposedly to feed fuel from the front to the back carb.
So why does this fuel line from the pump go to both carbs I was wondering?
I look and look at the diagram in the book and it just hits me - there's a fuel feed hose to the front carb but the back only has "breather pipe" and "vent hose" connections on the right side - no fuel feed in over there as the fuel feed in is on the left side of that carb!!
So - what happens when you feed fuel into the carb via the 'vent tube' or the 'breather pipe'?
Whatever it is, I will bet it isn't good!!!
Going out to make it look like the book right now. Will report soon.
SilentUnicorn
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Re: Well my Midget made it home...
interesting. I would imagine it would cause flooding issues...
m
interesting. I would imagine it would cause flooding issues...
m
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RickB
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Re: Well my Midget made it home...
OMFG you have got to get yourself one of these!!!
Ok, backing up a bit...
So as you might imagine hooking up the fuel so it only goes where it should and doesn't backfeed into the VENT made everything way way better.
A little adjusting and OFF TO THE RACES!!!
Wow - the GX head and a pair of 1.5 inch carbs is WAY freaking better performance than the econo head and the little hitachi downdraft.
I take off from the line now like amazing and it just pulls and pulls and pulls.
This is nothing short of amazing!!
So - to summarize...
Datsun A15 motor with a GX performance head and a pair of SU's = AWESOME!!!
Add a 5 speed and maybe I'll just have to feel like I've died & gone to heaven.
Yeah, it's that good!
OMFG you have got to get yourself one of these!!!
Ok, backing up a bit...
So as you might imagine hooking up the fuel so it only goes where it should and doesn't backfeed into the VENT made everything way way better.
A little adjusting and OFF TO THE RACES!!!
Wow - the GX head and a pair of 1.5 inch carbs is WAY freaking better performance than the econo head and the little hitachi downdraft.
I take off from the line now like amazing and it just pulls and pulls and pulls.
This is nothing short of amazing!!
So - to summarize...
Datsun A15 motor with a GX performance head and a pair of SU's = AWESOME!!!
Add a 5 speed and maybe I'll just have to feel like I've died & gone to heaven.
Yeah, it's that good!
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