• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

SU Carb Questions

Share this page

M

mxp01

Jedi Warrior
Country flag
Offline
All:

I have a pair of SU HS1 carbs on my BE. The car has not been running for awhile and I am not sure for how long these carbs have been sitting. They look great - they appear essentially brand new. The issue is that when I started the car up recently they leaked consistently. I tightened everything possible on the carbs, but they continued to leak. So, I removed the carbs, ordered a set of new SU gaskets, and am preparing to tear down the carbs in order to replace the gaskets.

Before I begin that step I have a few thoughts/questions:

1. I feel that the leaks are coming from either the cork or rubber gaskets. If the carbs sat for an extended period of time isn't it reasonable to conclude that the gaskets dried up/out and could not prevent the leaking of fuel.

2. The replacement set included a note instructing me to be sure to soak all cork gaskets for 24 hours. This seems to reinforce my feelings regarding dried gaskets.

Based on these thoughts, does anyone recommend a different approach besides a complete tear down of the carbs and replacement of all of the gaskets?

MXP
 
My prior experience with leaking (carbs that is :wink-new: ) has almost always been due to the Grose jets that control the entry of fuel into the float-bowls. They can get sticky (thus overflowing). I'd be certain that the floats are properly set (easy to do) and that the jets/valves are operational. I switched to the Viton-tipped valves to the floats.
 
Agree with Mark. This is a problem with the float valves. Sometimes, you can just take them out and clean them to stop the leaking.

Keith
 
OTOH SU's are simple to work on, just make sure you don't mix up the parts, and, there is the added bonus that if you dismantle and reassemble an SU enough times, soon you will have another. :grin:
 
Those carbs are an older re-build that were never installed on the engine until the engine was being tested at East Tennessee Race Prep a few months before you picked the car up. There were no issues then, however being an older rebuild that sat on the shelve for many years, I could imagine that some adjustment would be necessary.
 
Whitephrog said:
Those carbs are an older re-build that were never installed on the engine until the engine was being tested at East Tennessee Race Prep a few months before you picked the car up. There were no issues then, however being an older rebuild that sat on the shelve for many years, I could imagine that some adjustment would be necessary.
Click to expand...

with this knowledge, another option might be to soak the entire carb for 24 hours - it won't hurt the carb and it won't disturb the settings. Then you could see about the floats.
 
Sitting is not good for anything
I picked a couple NOS quadra jets and a holly all need there soft parts replaced.
 
Back
Top