How best to set up a Lister A

[Mick Patrick]

My Lister A will only run at a very rich idle with barely any air valve opening - any ideas please ?

[38ac]

I am not a expert on them by any measure but all 4 of my Lister gasoline engines run nicely with the fuel valve opened a very small amount , less than 1/2 turn. I would guess that your carburetor jet is partially plugged or your fuel supply is lacking.

[Mick Patrick]

Hi 38ac,

My fuel is opened about 15degs from closed which seems reasonable and I can easily admit more fuel but that makes it worse. The air is only just cracked from full closed and closing or opening makes it run at top speed with no control or starves it of air. There seems to be no sweet spot between. I wondered about the governor valve, if that was preventing a happy setting. ? My Lister D is great but this Lister A is really difficult to set right.

[cobbadog]

Hi Patrick,
Stationary engines in general can be a real challenge so keep persisting with it. Is this engine throttle governed or governor set rev range? If throttle governed then it is all about fuel / air mix ratios and is trial and error. If it is set by the governor then it has to be set at a lower speed then keep playing with the settings. You should be able to have your air intake open a bit more than you are describing.

[38ac]

 Now that you have better explained exactly what is going on Yes, you have givernor problems.  Could be that the linkage is not adjusted correctly, could be binding, could be internal issues, could be that someone has installed a spring that is to strong. Start out by verifying that the linkage will move against the pressure of the spring.

[cobbadog]

Thinking a bit more about your issue and to add to the good information from 38ac, also look at and repair any wear in the linkages to get it to run smoothly. Wrong tension springs can cause this trouble as can internal sticking so maybe a clean up on the inside as well.

[Mick Patrick]

Guys, thanks for the comments re the rough running Lister A. I have a new rather strong spring on the throttle adjuster so I have lengthened that with a bit of locking wire. Today I noticed that the governor springs do not reset back to an idle position so I will change them Maybe then I can get a good datum to start from. I am not sure about the carb slide valve in the air inlet, is it admitting too much air so that the adjustable air valve is only just cracked open. Any comments ?
Cheers Mick

[cobbadog]

Not having a Lister A with a carby I am unable to comment on it. Sounds very strange that one is wide open and the other nearly closed.
Keep playing and trialing different spring weights on the governor and get that sorted as this may make a difference when it is time to do the fine tuning of the carby. With the carby is it in good condition? By this I mean any fuel leaks, leaky gaskets or movement on the main shaft. A carby on my David Brown Cropmaster was almost impossible to tune. After sitting down with some plate glass and wet n dry paper I resurfaced all mating surfaces to stop air leaks. I then noticed that the main shaft ran on tiny needle roller bearings and there was suppose to be felt washers on the outer side of the throttle body to seal it from sucking air. I even made a set of gaskets for the carby body from top to bottom only to find out they dont normally have any gaskets there. It turns out that by resurfacing and fitting felt washers on the shaft I can now tune the tractor as it was meant to do so.
Keep a close look on all surfaces and gaskets and next time you have it running try the spray can of WD40 or similar and spray targeted areas to see if the RPM changes. If the revs alter you have an air leak.

[Mick Patrick]

Thanks Cobbadog,
When I get back from a working trip I will change the governor springs and free up any sticky bits. Good call on air leaks, I must be sucking air into the carb or gaskets so that's the next job. Cheers. Mick

[cobbadog]

This might make you laugh, after making all the gaskets for my carby on the tractor I found that they are not suppose to have any in them only a manifold gasket. This also explained why I had to reset the float level. 
Aslo check sticky valves, I had an issue with another engine and it was just that.

[glort]

This might make you laugh, after making all the gaskets for my carby on the tractor I found that they are not suppose to have any in them only a manifold gasket.

I can see where you would make that mistake. Never heard of a carb without gaskets before. you would think if they could make the carb seal they could make the manifold seal as well.

I remember making an exhaust manifold seal once.
I won't embarrass myself admitting how long it took me to figure the engine wouldn't start because I forgot to cut the hole for the exhaust to come out the port. Sure did seal well!

[dieselspanner]

The distortion of mating surfaces is common on the old Zenith' from the '60's as well, makes them impossible to set up, as noted by Cobbadog, plate glass and wet and dry.

Cheers
Stef

[BruceM]

Permatex gasket maker (doped gray silicone) has been a reliable leak fix for me.

[Mick Patrick]

Thanks everyone. Can`t wait to get back home to the bits in the post to have a crack at it. Glort, you got guts to admit to that, respect you for that old chap. Mick

[glort]

Glort, you got guts to admit to that, respect you for that old chap.

Ah Well, when you have done as many stupid things as I have, that's pretty low down the scale.
Was stupid/ funny enough for me to remember though.  I know why I did it, I was SO intent on getting the stud hole spacing perfect  ( accuracy is NOT my Forte) I guess I was so excited when I got it right I got too excited to fire the thing up and prove it and forgot the most important bit.
 I did get the main hole precise as well in the end by tapping round the port with a small hammer to cut the hole on the edge.

Sure was a long winded simple job though!   

One thing I learned a long time ago was you need to be sparing with all those sealants. The mating faces of anything you use it on should be pretty close to start with. You only need to fill the low spots and the rest will squeeze out. What comes out of the part is OK, what goes in can be a problem if it's more than a tiny bead.