Ransomes MG 40 600CC petrol engine with Amal carburettor

[janbru50hotmail-co-uk]

The problem I have with the above named machine is it will not slow idle when hot.
If I can catch it on the throttle it emits a large puff of black smoke.
Has anyone else encountered this problem. I would be most grateful for any help or advice.
Many thanks
Bruce leonard

[ransomes256]

Bruce,
Is this the 356/1 carburettor? It may be that the internal cross drillings are becoming blocked and may need an ultrasonic clean to clear them. It is not easy as the cross drillings are end blocked after manufacture. Additionally have you checked the jets and emulsion tube which sometimes gets a split or the solder end plug is missing.
Potentially it may also be related to a weak spark so may be magneto related.
email me if you need parts or more help njarrett@btinternet.com
Neil

[janbru50hotmail-co-uk]

Hi Neil thank you for your reply I will try all the items you suggest the carburettor is now off the tractor I have found some numbers on the front mounting flange upper is not at all clear but looks like 399/5 lower 172. I will check the emulsion tube this afternoon.
I had the magneto overhauled earlier this year by a firm called Armoto so that should be ok.
You may remember a couple months ago I could not find the sump plug well I took the engine out of the frame and found it on the opposite side of the frame from the large cutaway so i drilled a 76mm hole in the frame and that is all good now, but I wonder if at some time in the past if it has had an engine change.
I will look on the internet for a ultrasonic cleaner.

[ransomes256]

I think you will find the carburettor may be a 398/5 which has an oblong fuel bowl rather than round. This was a very late fit part and mainly by water boards etc. I do not know much about these but have never seen an issue with one.

[janbru50hotmail-co-uk]

Hi again Neil.
Yes definitely an oblong float chamber, looking at the throttle cable attachment it looks like a bodge job and coupled with the sump plug it appears likely my tractor is a bitzer.
Would there be any chance of getting one of the right carburettor’s for it from a scrap one? I will get an ultrasonic cleaner and give that a go I have checked the emulsion tube & the plug is in place. It doesn’t seem very likely you will have a float chamber gasket, the original one is intact but very limp I may be able to make a new one.
Thanks again.
Bruce Leonard.

[ransomes256]

I have new old stock 398/5 carburettors but no spares. Chances of getting a 356/1 is slim.

[janbru50hotmail-co-uk]

Hi Neil.
Thank you for your reply what is the price of your new carburettor?
Could you please send me your stock list again as unfortunately I have lost the one you sent me.
Thank you.
Bruce Leonard.

[ransomes256]

Please send me an email. njarrett@btinternet.com

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