Lister SL3

[Alvin]

Have asked similar questions, but need some idiots guide to this mechanism. Have set fuel pumps to manual which seems to set the rack movement to be only zero to 0.10inches from start/run/stop. Beyond this the governor controls speed? Should this link to governor via spring feel very light or have some resistance? Is it possible to have the link fall out of engagement with the governor lever arm? Any guidance please will be very grateful. Have left emails with Peter Thompson at marengservices but guess he may be on holiday

Thanks Alvin

[Tony Brooks]

Have asked similar questions, but need some idiots guide to this mechanism. Have set fuel pumps to manual which seems to set the rack movement to be only zero to 0.10inches from start/run/stop. Beyond this the governor controls speed? Should this link to governor via spring feel very light or have some resistance? Is it possible to have the link fall out of engagement with the governor lever arm? Any guidance please will be very grateful. Have left emails with Peter Thompson at marengservices but guess he may be on holiday

Thanks Alvin

 

 

As you have been waiting a while I will give my opinion but defer to Peter or Baldock. I only know SL4s from 30+ years ago, but expect the governor to be similar.

 

If you scroll down link to article until you come to The Mechanical Governor it will give you the general idea about how it works. The fuel delivery and metering is done in the same way as the In-line Pump section except you have 3 individual pumps as opposed to a number of elements in a single pump body.

 

I seem to recall that the SL4s had another light governor spring inside the main one that could have its tension adjusted from outside the throttle lever housing and this as used to give a better control of idle.

 

I can not remember anything about how the governor spring was attached and have the impression that it was always under slight tension between two cups. I am far from clear on this.

 

Now I wonder if you are asking about a marine (variable speed) version of the SL3 or a fixed speed version that you are perhaps trying to convert for variable speed use. As far as I can recall the rack movement on the SL4s was closer to 1/4 inch, perhaps more once the excess fuel button was activated. I would expect far less movement on a fixed speed governor and if you have one you will have to phone Peter at Uxbridge.

 

That 0.1" seems to be similar to the clearance that is required between the rack assembly and the thrust pad on the bob-weights, actually I think the Lister gauge was for 1/8" so 0.1" is similar. Over and above that you have to compress the governor spring - operating the stop is often the easiest way to see just how far the rack moves.

 

I also know that if any of the pumps are twisted or out of line the whole rack assembly can get very stiff and with limited movement so hold the stop in the stop position and make sure the rack moves freely.

[Alvin]

As you have been waiting a while I will give my opinion but defer to Peter or Baldock. I only know SL4s from 30+ years ago, but expect the governor to be similar.

 

If you scroll down link to article until you come to The Mechanical Governor it will give you the general idea about how it works. The fuel delivery and metering is done in the same way as the In-line Pump section except you have 3 individual pumps as opposed to a number of elements in a single pump body.

 

I seem to recall that the SL4s had another light governor spring inside the main one that could have its tension adjusted from outside the throttle lever housing and this as used to give a better control of idle.

 

I can not remember anything about how the governor spring was attached and have the impression that it was always under slight tension between two cups. I am far from clear on this.

 

Now I wonder if you are asking about a marine (variable speed) version of the SL3 or a fixed speed version that you are perhaps trying to convert for variable speed use. As far as I can recall the rack movement on the SL4s was closer to 1/4 inch, perhaps more once the excess fuel button was activated. I would expect far less movement on a fixed speed governor and if you have one you will have to phone Peter at Uxbridge.

 

That 0.1" seems to be similar to the clearance that is required between the rack assembly and the thrust pad on the bob-weights, actually I think the Lister gauge was for 1/8" so 0.1" is similar. Over and above that you have to compress the governor spring - operating the stop is often the easiest way to see just how far the rack moves.

 

I also know that if any of the pumps are twisted or out of line the whole rack assembly can get very stiff and with limited movement so hold the stop in the stop position and make sure the rack moves freely.

Hi Tony,

Thank you so much for this comprehensive reply, I look forward to reading through all pages with great interest. To answer your questions above, the racks did move freely until I made mistake of putting some oil on it. Had been very dry from parafin cleaning for many months. Now very sluggish, but assume once diesel is in system should free up. The rack setting was based on aligning calibration marks on two pumps to within 0.005 of side of pumps, by adjusting centre turn screw. Placing shim0.028/0.032 to lock locating plate. the resulting movement was 0.090/0.102. according to page 32 of Lister Book 650

thanks again Alvin

[Tony Brooks]

Hi Tony,

Thank you so much for this comprehensive reply, I look forward to reading through all pages with great interest. To answer your questions above, the racks did move freely until I made mistake of putting some oil on it. Had been very dry from parafin cleaning for many months. Now very sluggish, but assume once diesel is in system should free up. The rack setting was based on aligning calibration marks on two pumps to within 0.005 of side of pumps, by adjusting centre turn screw. Placing shim0.028/0.032 to lock locating plate. the resulting movement was 0.090/0.102. according to page 32 of Lister Book 650

thanks again Alvin

 

 

Alvin,

 

Sorry I no longer have access to the manual.

 

I trust your reference to the "centre turn screw" relates to the rod thing with a thread on each end that links the actual pump racks together. I seem to recall these pumps have a screw locating the internal parts more or less in the centre of the pump body. I hope you have not touched this.

 

I think you will have to get the rack freed off before you try to run the engine, otherwise I can see some very high revs occurring and possible a large, expensive bang.

 

My advice would be to remove all the link pieces between the pumps and check each pump rack. It should be easy to move each rack. If not you will know where the problem is. If it only stiffens up after you refit the pump links then I would suspect one nor more pumps have twisted on their base (or one is not clamped down properly, but usually its twist).

 

I hope that the reference to months and paraffin does not indicate it has been submerged. If it has and if water displaced the diesel in the pumps you may have one or more pump elements seized up. Removing the links should show which or if this is the case.

[Alvin]

Alvin,

 

Sorry I no longer have access to the manual.

 

I trust your reference to the "centre turn screw" relates to the rod thing with a thread on each end that links the actual pump racks together. I seem to recall these pumps have a screw locating the internal parts more or less in the centre of the pump body. I hope you have not touched this.

 

I think you will have to get the rack freed off before you try to run the engine, otherwise I can see some very high revs occurring and possible a large, expensive bang.

 

My advice would be to remove all the link pieces between the pumps and check each pump rack. It should be easy to move each rack. If not you will know where the problem is. If it only stiffens up after you refit the pump links then I would suspect one nor more pumps have twisted on their base (or one is not clamped down properly, but usually its twist).

 

I hope that the reference to months and paraffin does not indicate it has been submerged. If it has and if water displaced the diesel in the pumps you may have one or more pump elements seized up. Removing the links should show which or if this is the case.

Hi Tony,

Have not touched centre screw in pump bodies. No they were not submerged, just sprayed externally to clean. One pump was seized when setting rack, replaced with spare from old engine same serial No. onto existing shims bit of a chance I know, but hope will be OK. Been advised to have a rag bung ready to stop air intact if engine runs too fast. Although not this far yet. Want to check that governor link tee end (in manual) is still engaged at top of governor arm. Manually turning engine via pulley 'cam out' means cannot fit injectors yet with too much compression. regards Alvin