Engine losing power after running for an hour

[moiuk]

1 hour ago, magnetman said:

PRM Delta uses ordinary engine lube oil. 

 

It is the smaller mechanical type that use ATF. 

 

 

@moiuk if you stop the engine when this happens can you turn the shaft by hand? 

 

 

 

Of course if the shaft is very hot this might be a bad idea so check temperature. 

 

I wonder if there is an internal problem with the gearbox which can cause it to lock up in forward gear. 

 

A called to PRM NEWAGE might be worthwhile. 

 

Its a PRM Delta / PRM 150

 

 

 

 

 

 

 

I will (carefully) check if I can move it by hand next time.

Giving prm a call for their thoughts is a good idea 🙂

33 minutes ago, MtB said:

 

That's interesting. Would you say the boat goes noticably slower at tickover when the problem is present, than it goes at tickover when it is not present? 

 

Also, I've not noticed if you've said whether the exhaust smokes badly when the problem is present and you put the speed control to MAX. Or if anyone even asked! 

 

And does the engine rev up ok when in neutral? 

 

 

No significant smoke from the exhaust (some when initially starting).

 

Revs up ok when in neutral.

[magnetman]

If it is the plummer / pillow bearing it must be getting incredibly hot if its slowing the engine down. 

 

 

Edited August 17, 2023 by magnetman
double image

[moiuk]

4 minutes ago, magnetman said:

If it is the plummer / pillow bearing it must be getting incredibly hot if its slowing the engine down. 

 

 

I have a temperature sensor, so I will check temperatures around bearing/gearbox/stern gland next time it happens..

[MtB]

3 minutes ago, moiuk said:

I have a temperature sensor, so I will check temperatures around bearing/gearbox/stern gland next time it happens..

 
A Mark 1 hand is all you need. 

 

If you touch something and you need hospital treatment, you found the problem! We are not looking for somthing  ‘quite hot’, we are looking for something nearly glowing red hot. If there is something actually physically slowing the engine down, tge energy it is absorbing is huge and it will dissipate as heat. LOADS of it!

 

[magnetman]

I think its inside the gearbox. Hopefully not but it seems plausible something inside is seizing up when hot. 

 

A bearing perhaps. 

 

Infrared thermometer would be a very handy thing to wave around. 

 

I have exactly the same type of pillow block flange bearings on my boat in the same position and they get noisy if not kept greased. Have not had one binding up and seizing but I suppose it is possible. They are quite heavy duty bearings. 

 

Perhaps if the tailshaft was bent a tiny bit from a previous incident it could lock up inside the stern tube when under load but again there would be masses of heat. 

 

 

 

 

[MtB]

14 minutes ago, magnetman said:

I think its inside the gearbox. Hopefully not but it seems plausible something inside is seizing up when hot. 

 

I'm inclined to agree. 

 

Didn't the OP feel the need to change the oil right near the start of the thread? Why was that I wonder... maybe it had been boiling with all the engine energy being absorbed...

 

 

 

 

Edited August 17, 2023 by MtB

[Stilllearning]

I'd be tempted to go for the easy cheap tests first, stuffing box overtight, plummer block bearing, then look at uncoupling shaft from box, push it back and see if it's worn.

Cheap and easy first.

[magnetman]

I wonder what happens if someone puts ATF in a PRM hydraulic gearbox instead of 15/40 oil. 

 

Would it work? Might it damage the bearings? Don't know. 

 

I'm thinking of things which might have happened to the gearbox previously. 

 

My mum had a small Hurth mechanical gearbox which ejected the ATF through the filler which had vibrated loose.  It stalled the engine. The clutch pack had obviously seized up. I was able to unseize it with a spanner on one of the output coupling bolts. After that refilled with ATF and it worked fine. 

 

Gearboxes are relatively complex and things can go wrong inside if conditions are not ideal. 

 

[moiuk]

1 hour ago, MtB said:

 

I'm inclined to agree. 

 

Didn't the OP feel the need to change the oil right near the start of the thread? Why was that I wonder... maybe it had been boiling with all the engine energy being absorbed...

 

 

 

 

I try and change the engine oil every 2 months when moving. It's an old engine, and seems so happier after fresh oil..

[Tony Brooks]

1 hour ago, magnetman said:

wonder what happens if someone puts ATF in a PRM hydraulic gearbox instead of 15/40 oil. 

 

I doubt anything would happen unless it attacked the clutch plates. ATF has good lubricating properties so unless it is thin enough to cause a lack of hydraulic pressure the box should work.

[magnetman]

 

Another question must be is there a gap between the propeller and the external part of the stern tube? Usually there should be a gap there but its possible there isn't. If there was no gap or a very small gap and something such as a piece of wire had found its way into this tiny gap it could wound itself round and caused significant friction between the propeller boss and the stern tube itself. As it is external it would not show up as heat but it might be more problematic in forward gear because of the rubber coupling taking up a tiny bit of thrust and pushing the prop hard against the stern tube. 

 

There is probably a gap. There should be a gap. 

 

I'm wondering if someone replaced the rubber coupling at some point and the effect was to pull the propeller closer or even up against the stern tube. 

 

 

[moiuk]

3 hours ago, magnetman said:

 

Another question must be is there a gap between the propeller and the external part of the stern tube? Usually there should be a gap there but its possible there isn't. If there was no gap or a very small gap and something such as a piece of wire had found its way into this tiny gap it could wound itself round and caused significant friction between the propeller boss and the stern tube itself. As it is external it would not show up as heat but it might be more problematic in forward gear because of the rubber coupling taking up a tiny bit of thrust and pushing the prop hard against the stern tube. 

 

There is probably a gap. There should be a gap. 

 

I'm wondering if someone replaced the rubber coupling at some point and the effect was to pull the propeller closer or even up against the stern tube. 

 

 

This is a good shout. When the issue started I checked the prop and there was a length of wire wrapped around it. Not enough to cause the issue so only dismissed it . But. Perhaps a piece has got caught in a gap that I missed... I will check that and let you know.

 

Didn't go far tonight as wanted to enjoy a BBQ, so will have to wait for updates on the things I need to check 🙂

[magnetman]

Where are you on the River ?

 

Its turned out nice although tomorrow looking a bit wrong on the forecast. 

[moiuk]

Yuck ... Where did tomorrows forecast come from !!

 

Just above reading ATM.

[Bee]

You need to concentrate on the shaft, stern gland and that bearing. I don't recognise that plummer / pillow bearing but it should be a proper thrust bearing as the Fenner tyre coupling will not take thrust, it will pull apart in reverse or force the tyre off in forward. It might possibly be over stressed and be taking all the thrust on a grub screw sitting in a dimple in the shaft. It could be getting hot and the same goes for the stern gland itself. Hopefully all will be well and we can all think again.

[moiuk]

Not been very far in last few days so not had the issue again yet. I did take some temperature readings after running the engine for 30 minutes which are below and look kinda normal, so whatever the problem is it seems to start all of a sudden after an hour or two.

 

Temperature readings:

Gearbox 43

Thrust plate 32

Bearing 29

Gland 25

[Alan de Enfield]

6 minutes ago, moiuk said:

Not been very far in last few days so not had the issue again yet. I did take some temperature readings after running the engine for 30 minutes which are below and look kinda normal, so whatever the problem is it seems to start all of a sudden after an hour or two.

 

Temperature readings:

Gearbox 43

Thrust plate 32

Bearing 29

Gland 25

 

I'd suggest that the gearbox at 43 (I assume degrees celsius) is a bit on the hot side.

Metal held at 50 degrees C is rated as giving 1st degree burns.

 

I don't recall, ever touching my gearbox and thinking 'ouch' even after 8 hours of running - let alone 30 minutes.

[Bee]

43 for the gearbox is maybe a bit warm but I don't really know. Still uncertain whether its engine or gearbox/drive train. when it starts to lose power put it out of gear, grab that rubber tyre and see if the shaft turns easily, it should do, if it doesn't then its gearbox / drive train. I had a hire boat once that did this, turned out to be diesel bug and blocked filter.

[Tony Brooks]

1 hour ago, Bee said:

43 for the gearbox is maybe a bit warm but I don't really know. Still uncertain whether its engine or gearbox/drive train. when it starts to lose power put it out of gear, grab that rubber tyre and see if the shaft turns easily, it should do, if it doesn't then its gearbox / drive train. I had a hire boat once that did this, turned out to be diesel bug and blocked filter.

 

Which I suggested on 16th August and asked, as a diagnostic question, when was the bottom of the fuel tank last cleaned. Guess the reply.

[blackrose]

2 hours ago, Alan de Enfield said:

I'd suggest that the gearbox at 43 (I assume degrees celsius) is a bit on the hot side.

Metal held at 50 degrees C is rated as giving 1st degree burns.

 

I don't recall, ever touching my gearbox and thinking 'ouch' ...

 

I think you'd need to keep your hand held against metal at 50C for quite a long time to get a first degree burn which may be why you've never had a burn from your gearbox.

 

If the coolant from an engine running at 80 or 85C is being used to cool a hydraulic gearbox then a gearbox temperature of 43C seems reasonable to me.

[moiuk]

25 minutes ago, Tony Brooks said:

 

Which I suggested on 16th August and asked, as a diagnostic question, when was the bottom of the fuel tank last cleaned. Guess the reply.

My plan is to check a few easy things next time it happens.. the drive shaft still rotates by hand, and check the temperature of the parts when it shows itself..

 

If this doesn't narrow it down I'll look into the fuel which is a bit harder for me as I've not done that before.

 

Appreciate your input 🙂

[Alan de Enfield]

3 minutes ago, blackrose said:

I think you'd need to keep your hand held against metal at 50C for quite a long time to get a first degree burn which may be why you've never had a burn from your gearbox.

 

 

In offering advice on safe surface temperature for touch, the two key parameters include what the material is made of and duration of contact to cause a specified level of burn.

Below is a summarised table assuming contact with fingers or palm of hand (not sensitive skin areas) and for temperatures which could cause indicated burns for the indicated contact duration.

 

1st Degree Burn (minor burn):

• Non-metallic 85°C brief contact

• Metal 60°C brief contact

• Metal 50°C hold

2nd Degree Burn (damage to underlying tissue):

• Metal 100°C for 15 seconds contact

• 82°C for 30 seconds contact

• 71°C for 60 seconds contact

[Tony Brooks]

7 minutes ago, moiuk said:

My plan is to check a few easy things next time it happens.. the drive shaft still rotates by hand, and check the temperature of the parts when it shows itself..

 

If this doesn't narrow it down I'll look into the fuel which is a bit harder for me as I've not done that before.

 

Appreciate your input 🙂

 

Assuming a typical narrowboat fuel tank locations.

Accumulate a number of plastic milk cartons, 2 litres seem the most manageable.

Get a length of clear plastic hose of say about 3/8" diameter and push a "wand" made of copper pipe in the end and bend it slightly.

Put a milk bottle on the baseplate with the other handy and one beside/behind it.

Put the copper pipe into the fuel filler and onto the bottom of the tank.

 

Now the bit you need to get used to the taste.

 

Give the other end of the plastic pipe a good suck and put your finger over the end of the pipe in your mouth to seal it.

Put pipe end with finger over the milk carton and release your finger, push hoes into the milk bottle so the syphon you created starts to drain the tank

Sweep the wand all over the bottom of the tank, paying special attention to the tank bottom to side joint areas.

As each milk carton fills move, a new one to be filled.

Keep going until there are no more dark bits coming up with the fuel and until the fuel in the plastic hose is a nice clear red colour.

 

Once you get the bits together, it should all be doe in 15 minutes.

 

You can stop at any time by lifting the hose higher than the fuel level in the tank, and even come back when you have accumulated more milk cartons.

You can use a syphon pump or in some cases an oil change pump or a Pella extractor but a length of plastic pipe and copper pipe is cheaper.

 

If you let the milk cartons stand for a week, the clean fuel can be carefully poured off, leaving the water, emulsified fuel and dirt in the bottom.

Post some photos of what settled out.

 

 

 

 

 

 

[magnetman]

I had thought burns were like murder. 

[moiuk]

2 minutes ago, Tony Brooks said:

 

Assuming a typical narrowboat fuel tank locations.

Accumulate a number of plastic milk cartons, 2 litres seem the most manageable.

Get a length of clear plastic hose of say about 3/8" diameter and push a "wand" made of copper pipe in the end and bend it slightly.

Put a milk bottle on the baseplate with the other handy and one beside/behind it.

Put the copper pipe into the fuel filler and onto the bottom of the tank.

 

Now the bit you need to get used to the taste.

 

Give the other end of the plastic pipe a good suck and put your finger over the end of the pipe in your mouth to seal it.

Put pipe end with finger over the milk carton and release your finger, push hoes into the milk bottle so the syphon you created starts to drain the tank

Sweep the wand all over the bottom of the tank, paying special attention to the tank bottom to side joint areas.

As each milk carton fills move, a new one to be filled.

Keep going until there are no more dark bits coming up with the fuel and until the fuel in the plastic hose is a nice clear red colour.

 

Once you get the bits together, it should all be doe in 15 minutes.

 

You can stop at any time by lifting the hose higher than the fuel level in the tank, and even come back when you have accumulated more milk cartons.

You can use a syphon pump or in some cases an oil change pump or a Pella extractor but a length of plastic pipe and copper pipe is cheaper.

 

If you let the milk cartons stand for a week, the clean fuel can be carefully poured off, leaving the water, emulsified fuel and dirt in the bottom.

Post some photos of what settled out.

 

 

 

 

 

 

I have a Syphon pump, can I pull some fuel directly out from the bottom of the tank?