Lumpy choke issue.

[Stag About Town]

For a long time my Stag has started ok on choke but would immediately start running very rough and lumpy until I was able to warm it up enough to push the choke in. After that it ran ok. The other day I was looking around the engine with the air filter off from the elbows and just happened to put a spanner on the accessible nut out of the four that secures each carb body to the pedestal mounting. On both carbs I could tighten that accessible nut down about half a turn. The others are difficult to get at so I put the air filter back on and started the car. The result was astonishing with the car running much as it should on choke for the first time in ages. I have since tried to check the tightness on the remaining nuts and could just get a spanner on a couple of them and they seem to be ok. Why did a half turn that one nut on each carb make such a difference and any tips on how to get to the others? Many thanks in advance. John

[The cobbler]

I'm so glad you posted this, I've only owned my stag for a week, and every time I start it, it's just as you described, I'm going to check my carbs and nuts tomorrow, hopefully I will find the same issue.

[wilf]

Must have sealed an air leak.

[Stag About Town]

I'm so glad you posted this, I've only owned my stag for a week, and every time I start it, it's just as you described, I'm going to check my carbs and nuts tomorrow, hopefully I will find the same issue.

Will be interested to hear if it works for you but mystified as to why only one out of the 4 nuts on each needed a tighten as far as I could tell. The others are very hard to get at. Also, why did half a turn on one nut on each carb make such a difference? If the problem is that one of the hard-to-get-at nuts needs a spanner on it I'm not sure how to do it easily. As a non-mechanic, I would be nervous about tinkering with the carbs too much. Think Wilf is right about the air leak but just seems a bit odd. Just pleased that the cold start is now much as it should be.

[jbuckl]

As wilf says it will have sealed an air leak.

Any post throttle air leak disrupts the mixture.

There are many potential sources of air leaks.

Use a volatile spray to detect such as brake and parts cleaner.