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JP3 governor bell crank lever spring pt#028-218


baldrick
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Hi there,

we recently bought a Steve Hudson trad with a 1947 JP3 fitted by Hudson. I believe the the governor bell crank lever spring (the lever you move to shut the engine down) isn't the correct one. item 51 in the illustration below

does anyone know where to get a replacement? I have tried Redshaws, MPS & Slemann & Hawken limited but no one has one.

or has anyone got one spare for sale?

failing that the dimensions, wire thickness, number of coils of the correct springimage.png.9089285d35f8479d8c2b5c10dcf03d7f.png

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If you ever need a spring made Small Order Springs at Uxbridge are brilliant.  And handy for the canal.

 

Made me 10 Governor springs and 20 magneto impulse springs for a Kelvin J. Quick, good price.

 

Usual disclaimer.

 

N

 

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hello again,

  I have also ordered the two bearings for the stop lever, am I right in thinking it is just a split pin holding item 40 in place?

do I remove the split pin take off the cap and pull the lever off. the shaft item 39... or am I missing something? 🤔

On 18/10/2022 at 18:19, BEngo said:

If you ever need a spring made Small Order Springs at Uxbridge are brilliant.  And handy for the canal.

 

Made me 10 Governor springs and 20 magneto impulse springs for a Kelvin J. Quick, good price.

 

Usual disclaimer.

 

N

 

Bengo can you give small order springs a lister part number & they manufacture the spring, or dos you have to give all the dimensions of required item ?

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I just took the old ones in and collected the new ones about 4 days later.  They were very close to my alternative route from work to mooring.  I think I rang first to check.

 

Today, I would ring and sort out either what exactly was needed on a dimensioned sketch or fix  a postal delivery for an existing item.

 

N

 

Edited by BEngo
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I have no JP experience but extrapolating from spring size and the SL/SR range I think that if may be the idle adjustment spring that is used to help minimise surging at idle. If so there should be an adjustment for tension so an exact copy may not be required. Now those well versed in these things can tell me that I am talking ollocks.

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hi Tony,

               you may well be right, the governor rod runs through the centre of the spring and pushes the lever to slow the engine down if it overspeeds.

the spring fitted on mine has so many turns (11 or 12 turns if I remember correctly) that there is hardly any travel of the lever before the spring is fully compressed (all coils are touching)

             At the moment the engine speeds up quite noticeably then back to idle when moving the gear lever into neutral, for example you are creeping into a lock at tick over, pull the gear lever to neutral to coast the last few feet, the engine will rev up a fair bit then settle back to tick over .

 which at the moment is a touch to low I think,  should it be around 300 to 400 RPM ?

 

Not sure how to measure tick over either... some one said listen and count... ???

I thought of using an optical Tacho  that I have for measuring model airplane prop speeds.. stick a strip of white tape on the fly wheel and "jobs a fish' as they say

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50 minutes ago, baldrick said:

hi Tony,

               you may well be right, the governor rod runs through the centre of the spring and pushes the lever to slow the engine down if it overspeeds.

the spring fitted on mine has so many turns (11 or 12 turns if I remember correctly) that there is hardly any travel of the lever before the spring is fully compressed (all coils are touching)

             At the moment the engine speeds up quite noticeably then back to idle when moving the gear lever into neutral, for example you are creeping into a lock at tick over, pull the gear lever to neutral to coast the last few feet, the engine will rev up a fair bit then settle back to tick over .

 which at the moment is a touch to low I think,  should it be around 300 to 400 RPM ?

 

Not sure how to measure tick over either... some one said listen and count... ???

I thought of using an optical Tacho  that I have for measuring model airplane prop speeds.. stick a strip of white tape on the fly wheel and "jobs a fish' as they say

 

Optical tacho should be fine as long as it will read low enough.

 

Again, based on other engines I think you need to look at the main governor spring(s) because that one looks too light in the diagram.  I think will be off to the left of your diagram.  Thy may be worn or slack. It will be a good idea to ensure the control rod is free to move and has no tight spots.

 

I can't comment on the idle speed because I have no manual and no experience of that engine. Hopefully a knowledgeable member will be along soon.

 

 

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59 minutes ago, Tony Brooks said:

 

Optical tacho should be fine as long as it will read low enough.

 

Again, based on other engines I think you need to look at the main governor spring(s) because that one looks too light in the diagram.  I think will be off to the left of your diagram.  Thy may be worn or slack. It will be a good idea to ensure the control rod is free to move and has no tight spots.

 

I can't comment on the idle speed because I have no manual and no experience of that engine. Hopefully a knowledgeable member will be along soon.

 

 

I can't see any springs on the governor just 2 fly weights that appear to push on the forked end which in turn pushes the governor rod and moves the shut off lever to slow the engine down

Screenshot 2022-10-20 at 19.46.00.png

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There are no springs on the camshaft gear assembly.  The small compression spring on the governor push rod is there to damp the bell crank  There is an adjuster bolt on the arm which should be set to have a gap of 3mm or so between it and the governor rod. The gap and spring are there to reduce hunting at idle.

 

The critical item is the throttle spring (18) This must be of the correct length and poundage. Near enough does not do. The boats throttle control must include the spring. For example a rod or Morse cable must never be connected directly to the bell crank as it will prevent the proper operation of the governor. With the spring correctly installed the governor will always control the max rpm and greatly reduce the risk of an overspeed induced crankshaft failure to which JPs are prone, especially when worn.

 

The other item to check is the bell crank bearings, which are often neglected. If they are worn out there can be too much float and too much resistance if they seize up. The bell crank should operate without resistance or slop. If it is in poor condition it can also affect the idle and throttle response

 

 

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15 minutes ago, steamraiser2 said:

There are no springs on the camshaft gear assembly.  The small compression spring on the governor push rod is there to damp the bell crank  There is an adjuster bolt on the arm which should be set to have a gap of 3mm or so between it and the governor rod. The gap and spring are there to reduce hunting at idle.

 

The critical item is the throttle spring (18) This must be of the correct length and poundage. Near enough does not do. The boats throttle control must include the spring. For example a rod or Morse cable must never be connected directly to the bell crank as it will prevent the proper operation of the governor. With the spring correctly installed the governor will always control the max rpm and greatly reduce the risk of an overspeed induced crankshaft failure to which JPs are prone, especially when worn.

 

The other item to check is the bell crank bearings, which are often neglected. If they are worn out there can be too much float and too much resistance if they seize up. The bell crank should operate without resistance or slop. If it is in poor condition it can also affect the idle and throttle response

 

 

 

Thanks for identifying the throttle, or what I would call the governor, spring. From what you say I think it conforms the spring the OP was discussing is to minimize surging and the problem may well be else where. Something more for me to find space for in my brain.

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Hi Steamraiser2,

                             you mention a 3mm gap between the governor rod end and the adjuster bolt on the arm, is this with the engine stationary and the spring item 51 in place?

if this is the case then the spring on mine is definitely wrong, you would be hard pressed to get a feeler gauge between the spring coils and in the correct position between the rod end and the adjuster.

Also Is the speeder spring,  connected when setting this 3mm gap?  Won't any tension on speeder spring try and close the gap (speed up the engine) & the tension on the spring 51 open the gap and slow down/stop the engine.

my engine doesn't have the JPM lever with stops built in. It was an Ex MOD searchlight generator unit. it just has the stop lever with the little pin through it to hold the fuel injector pump in the stop position when shutting it down.

 

I have in fact ordered a new speeder spring, bearings and a cam unit (starting and O/speed protection as one isn't fitted to my engine) from MPS & a spring 51 from Primrose so when these arrive I will be able to replace the springs that are fitted and see if there is any improvement.... 

 

I am back at the boat tomorrow so can take photos to explain better

 

 

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1 hour ago, Tony Brooks said:

The other item to check is the bell crank bearings, which are often neglected. If they are worn out there can be too much float and too much resistance if they seize up. The bell crank should operate without resistance or slop. If it is in poor condition it can also affect the idle and throttle response

how would I remove the bell crank assy to replace the 2 bearings, is it just a split pin holding item 40 in place and are the bearings easy enough to push/tap out?

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37 minutes ago, baldrick said:
1 hour ago, Tony Brooks said:

The other item to check is the bell crank bearings, which are often neglected. If they are worn out there can be too much float and too much resistance if they seize up. The bell crank should operate without resistance or slop. If it is in poor condition it can also affect the idle and throttle response

how would I remove the bell crank assy to replace the 2 bearings, is it just a split pin holding item 40 in place and are the bearings easy enough to push/tap out?

If that is directed to me the answer is, I have no idea. As I said, I have no practical experience on these engines and that is what is needed to answer you (or a manual).

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2 hours ago, baldrick said:

how would I remove the bell crank assy to replace the 2 bearings, is it just a split pin holding item 40 in place and are the bearings easy enough to push/tap out?

27 minutes ago, baldrick said:

sorry Tony, I meant to ask it of Steamraiser2 

 

This should get his attention, @steamraiser2

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Just unbolt the whole assembly and dismantle on the bench. It's easy enough. The spring is not strong and it should be possible to  set the appropriate adjustment. If you can't  I would suspect that the spring is too long. As an after thought you should always have the cold start cam  fitted on the end of the fuel pump. All together the two springs and pump cold start cam will enable your engine to idle at a steady speed. It is common for narrowboat  owners to try and get their engines to idle too slowly. The idle speed is specification dependent but 400 to 420 is about the mark

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No. Push the governor rod in to take up any slack. Do not try to push the weights. Make sure the fuel pump has the cold start pawl fitted and that the pump rack is set at the normal running position ie:the  start pawl has dropped.  The throttle spring will naturally pull the bell crank towards the engine block. At the point when any movement of the spring is going to pull the fuel pump rack adjust the bell crank bolt to give a 3mm (ish) gap. All with the engine stopped of course. When the bolt is adjusted fit the compression spring

 Run the engine and set the idle by adjusting the tension on the throttle spring. The 3mm gap will enable the governor and fuel pump to float a little which is the object of the exercise.. Easy peasy. Typing this has taken longer than doing the job......!

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On 21/10/2022 at 08:39, steamraiser2 said:

There are no springs on the camshaft gear assembly.  The small compression spring on the governor push rod is there to damp the bell crank  There is an adjuster bolt on the arm which should be set to have a gap of 3mm or so between it and the governor rod. The gap and spring are there to reduce hunting at idle.

 

The critical item is the throttle spring (18) This must be of the correct length and poundage. Near enough does not do. The boats throttle control must include the spring. For example a rod or Morse cable must never be connected directly to the bell crank as it will prevent the proper operation of the governor. With the spring correctly installed the governor will always control the max rpm and greatly reduce the risk of an overspeed induced crankshaft failure to which JPs are prone, especially when worn.

 

The other item to check is the bell crank bearings, which are often neglected. If they are worn out there can be too much float and too much resistance if they seize up. The bell crank should operate without resistance or slop. If it is in poor condition it can also affect the idle and throttle response

 

 

 

Sorry for the thread hijack and slighty off topic but I did purchase a new throttle spring from yourselves a few years ago...and it doesn't fit!...as can be seen from the picture its too short for my existing control rod....and as also can be seen the existing spring is overstretched at one end. Im wondering if my control rod is actually not the right length...do you know what the right length is for a JP2M and if indeed you have/can make a new rod?

 

 

image.jpeg.372f12269bc1c0703f186576684521c6.jpeg

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1 hour ago, frangar said:

 

Sorry for the thread hijack and slighty off topic but I did purchase a new throttle spring from yourselves a few years ago...and it doesn't fit!...as can be seen from the picture its too short for my existing control rod....and as also can be seen the existing spring is overstretched at one end. Im wondering if my control rod is actually not the right length...do you know what the right length is for a JP2M and if indeed you have/can make a new rod?

 

 

image.jpeg.372f12269bc1c0703f186576684521c6.jpeg

I had the same issue and found a solution by adding a split 'keyring' ring to the end of the rod, which allowed the spring to be fitted without stretching it. Works perfectly. I notice your rod has a curved upsweep at the governor end, whereas mine is just straight and appears original. 

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