Aisan Carburettor high rev

[mnrsamuel]

lever1a.jpg (54.06 KiB) Viewed 5834 times

lever1.jpg (83.49 KiB) Viewed 5834 times

Greetings!

It all started when my rig started to hesitate. Well after a costly exercise of replacing the cam belt, tensioner - the " 4x4 Doctor" returned it to me without fixing the issue. I simply replaced the HT/Spark plug leads and that resolved the hesitation issue.

My rig now runs at +2000rpm and on acceleration goes up to 4000rm and sticks at this rev. Have serviced the carb with copious amounts of carb cleaner, checked the vacuum pipes and hoses (also checked by this "4x4 Doctor" - but again he could not figure the reason for the high rev). Have since replaced the throttle return spring.
I've read most of the high rev issue posts and implemented/checked the recommendations as well.
I should add that the rig was running perfectly before the hesitation issue.

None of the above has made any difference.

Today I discovered that the lever from the wax module was the culprit that was holding up the revs.
Refer to my pics - marked the lever with a red arrow.
As soon as I fiddled with the lever the revs came down to 900rpm.

Please, dear members, can anyone advise on either disconnecting this wax module or resolving this issue.


thanks,

[turbo-tom]

Im not 100% clued up on carbs. But possibly the auto choke maybe giving you problems?

[twiss]

The thermo wax controls the auto choke, it should expand and contract with temperature, moving various levers around. Its quite a common problem with these carbs so Tom may be correct.

I would try running the engine from cold with the airbox and plenum chamber disconnected.
The choke is the topmost butterfly valve. It should go from closed to open (or vice versa) as the engine warms up to temperature.

If it doesn't I would suspect the auto choke as tom says

[mnrsamuel]

definitely will try this.
Busy researching how to disable the auto-choke / wax module.

thanks for the prompt replies.

[twiss]

You can completely disable the autochoke by unscrewing and removing the butterfly disc i mentioned in the previous post... the problem is then that there is no choke and it will make it hard to start from cold!

[turbo-tom]

Hargly noticesble though mine fires up without it!

[mnrsamuel]

Don't mind the short time warming the rig up - small price to pay for changing gears at 4000rpm. Anyway, I'm in South Africa - morning winter temp is around 14 degrees Celsius

[twiss]

Its alright for some! haha
Yeah you should be fine without it then, even if its just to test it out!
Just be very careful when taking the screws out as the last thing you want is to drop them into the carb

[mnrsamuel]

just to close this thread with finality to the issue (hope everyone would report back on their findings/solutions - instead of leaving threads open)

Tried the removal of the throttle - did not solve the high rev issue.

In frustration, I have had the carb renovated.
It appears as if lots of junk ended up in the internals. I suspect this is from the "work" that the "4x4 Doctor" carried out! because the carb on the rig worked perfectly before the hesitation issue.
My rig is back to normal now

Moral of my story is - don't trust anyone who calls themselves doctor with proof of actual knowledge and semantics of the doctorate they hold.

regards to all,

[turbo-tom]

No worries glad its on the mend.