The Old Lawnmower Club
Collection, Preservation and Display of Old Lawn Mowers
X

Atco Commodore B17 Project

Enter a word or two to search the forum section and click the Search Forum button.
JNM Wed, 29/04/2020

I plan to restore an Atco Commodore B17 (Ser No 082758/K Commodore B17HT SER 2A).  The machine is in good condition and is powered by the A114-1A engine and fitted with the original Dellorto FHC 20-13A carb.  My first job is to remove and clean the carb and having looked at previous threads it would be an opportunity to replace the fixed 0.78mm inlet jet with the Dellorto adjustable jet which is available as a kit.  It appears that this modification was commonly undertaken by dealers to improve performance although never adopted by Qualcast/ATCO on the production machines.  Alternatively I was wondering if the Dellorto carb could be swapped out to be replaced by the Tillotson carb (and air filter) which I believe ATCO moved to in around 1990?  New Tillotson carbs are available from the OEM and if they improve the running of the machine that would be desirable.  Clearly this would not be viable if ATCO modified the inlet manifold or any other aspect of the machine which rules out or substantially complicates this option.  Would really appreciate advice on whether to:

  • Stick with the current Dellorto carb including retaining the original fixed inlet jet.
  • Modify the Dellorto carb with the adjustable jet kit - does this genuinely improve the reliability of the machine and make for easier starting?
  • Move to the Tillotson carb.  Is this carb an improvement?

I should add that the machine runs, but it needs the choke to be permanently open.

Many thanks for reading this post and look forward to hearing from anyone with experience of the Commodore machines. James

Forums

hortimech Wed, 29/04/2020

If your Dellorto carb is in good order and you can obtain the adjustable main jet kit, then this is the way to go. Any other carb will use a fixed main jet and these, to put it bluntly, were a pain the arse wink Any small amount of dirt meant that you had to run the engine on partial choke and this obviated the reason for the fixed main jet. If I could find the person who thought this was a good idea, I would tell them that they are an idiot and have no common sense or mechanical knowledge.