Perkins 4108, cold start manifold

[Kendorr]

Earlier this year my cold start manifold failed to glow. I purchased a replacement and fitted it. The new one works fine and glows red after a second or two. It is my understanding that when it glows, it should open a small valve, spray a little diesel in which will then ignite. This doesn't happen. The only way I can get it to work is to manually use the fuel lift pump rod, pressing it about 20 times, then turn the ignition and wait for the fuel to ignite. The engine will not start just from the red hot coil of the cold start manifold.

 

I suspect I need to replace the replacement part which was only about £10, but has anyone got any better advice to share?

 

Thanks in anticipation

Kevin

[mross]

Do you have a user's manual for the engine?  And is the fuel pump electric?

Quite a lot of info here http://www.cruisersforum.com/forums/f54/cold-start-heater-on-perkins-4-108-a-7203.html

You can order an 'operator and maintenance manual here but you need the first two letters of the engine serial number.

https://www.perkins.com/en_GB/aftermarket/operation-maintenance-manuals.html

Edited October 27, 2017 by mross

[Tony Brooks]

It depends upon how old it is and your maintenance. Earlier versions had a little diesel tank with a tap on it. A long as you turned the tap on and kept fuel in the tank it worked as you think it should. No fuel or tap off and it would not work.

Yours seems to be a later model with the flame plug fed from the fuel supply and I think it is working properly.

It works when you use the mechanical lift pump's priming lever because you are manually doing what the starer motor and the the running engine does - operate the lift pump. On a stationary engine there is nothing to pressurise the fuel so how will the fuel get to the flame plug? On some boats its possible that you MIGHT get a gravity flow so it works as you want it to but I doubt it will be many. Get someone to go through the starting procedure while you look down the inlet. I bet you will see the flame plug glow and then a few milliseconds after they hit the starter the flame will appear.

The reason it works as you think it should after  20 pumps of the priming lever is that you have manually pressurised the fuel system so the fuel pressure is holding the lift pump diaphragm down. As long as you are quick in starting the spring in the lift pump will be maintaining pressure BUT some should be slowly leaking back to the fuel tank  through the leak off system. If you were slow on the starting the flame would not appear because the pump spring would have pushed all the fuel (and any air) it can back into the tank and the pump diaphragm would not have been pulled down again to get another "spring" full.

PS - its not the manifold that glows, its a flame plug screwed into the inlet manifold - just so you do not appear ripe for conning when you talk to people about it.

Edited October 27, 2017 by Tony Brooks

[mross]

More info here http://www.ybw.com/forums/showthread.php?110944-Perkins-4-108-preheater/page2

In the 'glow plug' is a valve that opens when it's hot to allow a dribble of fuel.  This often comes from a small reservoir.  On yours it seems to need some pressure from the fuel system as the engine turns over.  When using the manual lever on the lift pump, remember that it only works when the engine is in certain positions.  If the pump's rocker arm is on top of its cam, the hand lever has no effect.

[X Alan W]

We had a piece of plant with a Perkins engine Though it was a six cylinder the start procedure used was to motor over on the stater for around  5 or so secs turn on the cold start & after around 10 secs motor over on the starter again after 6/8 revolutions it would fire up. If yours would start using this method it would be a try & see

[Kendorr]

Thanks folks, I'll have a good look later, need to get moving back to base soon.

I have got the manual, and, yes, I see the piece is called the 'Cold starting aid', of which mine is the mark 111 version.

Kevin

[mross]

Does your manual say how the fuel is supplied to the ThermoStart?  There's a nice video on YouTube showing what should happen.  Can you look into the air inlet, maybe with a mirror, while someone operates it?

 

[Kendorr]

So, this morning's start up.

1, Turned the key to pre heat, left it for 25 seconds then switched to ignition. The engine turns, white smoke out of the exhaust, but no attempt to start by the engine.

2, Pumped the lift pump 20 times, repeated as above, same result.

3, Pumped the lift pump another 20 times, but this time took the air filter cap off so I could see the cold start aid. After 5 seconds everything happened exactly as the video shown above and the engine started.

I've taken a couple of pics which might also help.

It's obviously doing what it should, but needs a little bit of help.

I will also add that the diesel tank was drained and cleaned before setting off cruising this year and both fuel filters were changed at the same time.

Kevin

[X Alan W]

you could try pumping your fuel pup a fewtimes before you turn on the glow plug unit & see if that aids starting  Getting fuel there before heat

[cuthound]

4 minutes ago, Kev's Halcyon said:

I will also add that the diesel tank was drained and cleaned

 

 

Weĺ that explains it.

Fill it up with diesel, bleed the air out and it should start. 

[Kendorr]

29 minutes ago, cuthound said:

Weĺ that explains it.

Fill it up with diesel, bleed the air out and it should start. 

......and then filled with new diesel 

Edited October 27, 2017 by Kev's Halcyon

[mross]

There's not much point pumping before the valve is hot as it won't open.  Unless you disconnect the fuel pipe and make sure there is no air in the pipe.

[Tony Brooks]

Have you tried the procedure that X Alan W suggested? Re-read my explanation of what is going on and you will see its a good idea.

[Kendorr]

21 minutes ago, Tony Brooks said:

Have you tried the procedure that X Alan W suggested? Re-read my explanation of what is going on and you will see its a good idea.

Thanks Tony, I haven't tried priming from the fuel pump, but will give that a go in the morning. I can stand directly above and when the pre heat is activated, withing 3 seconds the plug glows red, but however long I leave it, there is no flame. It is confusing because everything people are saying should happen is happening, apart from the valve opening to let a small amount of fuel through.

 

Thanks to everyone for the advice.

Kevin

[nb Innisfree]

Fuel is supplied from leak off pipes so Thermostart wont get any until engine is cranking. 

[Tony Brooks]

12 hours ago, nb Innisfree said:

Fuel is supplied from leak off pipes so Thermostart wont get any until engine is cranking. 

That is what I have been trying to say.

12 hours ago, Kev's Halcyon said:

Thanks Tony, I haven't tried priming from the fuel pump, but will give that a go in the morning. I can stand directly above and when the pre heat is activated, withing 3 seconds the plug glows red, but however long I leave it, there is no flame. It is confusing because everything people are saying should happen is happening, apart from the valve opening to let a small amount of fuel through.

 

Thanks to everyone for the advice.

Kevin

So if you have not been using the priming lever on the fuel lift pump what did you press 20 times?

 

[Tony Brooks]

I have been thinking about this overnight and have come to the conclusion I and others have been mislead by self diagnosis and a lack of information.

If we assume the think that was pushed 20 times was the lift pump priming lever (except I thought on Perkins it is pulled up) then as the thermostart/flame plug worked we know that the thermostat is working. From that it is reasonable to conclude the problem is something else.

In my experience the Perkins 4-10x series were good starters for most of the year in the UK, certainly I would not expect it to require the thermostart working yesterday after about 10 am. This makes me suspect there is another problem that the thermostart has been covering up.

Now two questions: -

1. is the starter spinning the engine fast enough?

2. if yes what are the compressions, this may be a worn engine.

If both those questions return satisfactory answers its fair to conclude its a fuelling issue. IF the compressions are OK this is  hinted at by the piece saying it cranked over but just made smoke, I would like to know how much.

I think the OP said he has had the tank cleaned - why? I suspect bug or a lot of dirt. In either case the fuel pump valves may be  jammed open by whatever it was, especially if the is no primary filter/water trap. Open valves would allow fuel to drain away from high points if there is the smallest air leak in the engine pipework and the boat has a low level tank.

There is another possibility because I suspect this is an old engine. The lift pump arm, camshaft eccentric and the levers inside the lift pump can and do wear. When they do the priming system can usually supply far more fuel that when the camshaft is working the pump. If this is the problem the symptoms are likely to be exactly what has been described.

If cranking for a few seconds before stopping to apply heat and then cranking again does not work then I think the lift pump needs to come off for investigation, especially if its one like Mross posted because it has no strainer on the inlet. Before taking it off I would disconnect an outlet pipe, direct it into a jar and crank the engine. You should get around a small eggcup full of fuel every two revolutions and rather more on each FULL stroke of the priming lever provided the camshaft is in the correct place. Very little on cranking and a bit more with the priming lever suggest a worn pump.

A further point is that the engine uses a DPA injector pump so once running the internal transfer pump mat well assist in drawing fuel into the engine.

As always a full history and description of ALL the symptoms helps a lot in solving problems.

[Kendorr]

Thanks Tony.

I know that a previous owner, 5+ years ago, would use the 'sure start' spray to get it going, this is something I have never resorted to.

When I purchased Halcyon, she was raw water cooled. 3 years ago I decided to have skin tanks fitted. This obviously required the engine to be removed. I asked the boat yard to check the bearings and it was found that the crankshaft needing a regrind. We also found a problem which meant the gearbox had to be scrapped and I had a PRM150 fitted. Once re-built and tested, everything was fine. Engine would fire up without any pre-heat most of the year, and when needing the pre-heat, it would only be a few seconds, even in the depths of winter.

The last 2 years I cruised for a good 3 months with no engine problems, apart from burning a bit of oil.

Early this year the engine wouldn't start and it was traced to the cold start aid. I bought a new one, fitted it myself and was very pleased when the engine started, albeit after the pumping procedure I've mentioned.

I'd changed both fuel filters November last year with genuine Perkins parts, then in April I was having a short trip out when the engine stalled just outside the boat yard who had done all the work previously. The filters were clogged and black and when the diesel was being drawn off, it also had a black tinge to it. As I had 2 trips planned which included journeys on the Trent, I took their advice and had them clean the tank out. It wasn't diesel bug, just years and years of dirt. They tested and fitted 2 new fuel filters.

I've started the engine at least 50 times since the work was done and I would say 45 of those have needed the priming procedure to get the engine to fire up.

I appreciate the points that the priming shouldn't be doing anything, but it does work and I get exactly what the video posted earlier shows, without the priming, I just get a coil glowing red.

 

I will also add that this is the first engine I've ever owned, being a non driver, so everything is new to me. Also, the engine runs and purrs sweetly once it has started up. Also, anyone who know Thorne will know that the people who carried out the work are very good and have an excellent reputation.

 

Thanks again folks, Kevin

 

[Tony Brooks]

3 minutes ago, Kev's Halcyon said:

Thanks Tony.

I know that a previous owner, 5+ years ago, would use the 'sure start' spray to get it going, this is something I have never resorted to.

When I purchased Halcyon, she was raw water cooled. 3 years ago I decided to have skin tanks fitted. This obviously required the engine to be removed. I asked the boat yard to check the bearings and it was found that the crankshaft needing a regrind. We also found a problem which meant the gearbox had to be scrapped and I had a PRM150 fitted. Once re-built and tested, everything was fine. Engine would fire up without any pre-heat most of the year, and when needing the pre-heat, it would only be a few seconds, even in the depths of winter.

The last 2 years I cruised for a good 3 months with no engine problems, apart from burning a bit of oil.

Early this year the engine wouldn't start and it was traced to the cold start aid. I bought a new one, fitted it myself and was very pleased when the engine started, albeit after the pumping procedure I've mentioned.

I'd changed both fuel filters November last year with genuine Perkins parts, then in April I was having a short trip out when the engine stalled just outside the boat yard who had done all the work previously. The filters were clogged and black and when the diesel was being drawn off, it also had a black tinge to it. As I had 2 trips planned which included journeys on the Trent, I took their advice and had them clean the tank out. It wasn't diesel bug, just years and years of dirt. They tested and fitted 2 new fuel filters.

I've started the engine at least 50 times since the work was done and I would say 45 of those have needed the priming procedure to get the engine to fire up.

I appreciate the points that the priming shouldn't be doing anything, but it does work and I get exactly what the video posted earlier shows, without the priming, I just get a coil glowing red.

 

I will also add that this is the first engine I've ever owned, being a non driver, so everything is new to me. Also, the engine runs and purrs sweetly once it has started up. Also, anyone who know Thorne will know that the people who carried out the work are very good and have an excellent reputation.

 

Thanks again folks, Kevin

 

The red bit - I still think that points to a fuel supply problem and nothing to do with the thermostart.

The blue bits - they lend some credence to the thought the compression is low, worn engine.

However test the fuel pump deliver firstr.

[Kendorr]

9 minutes ago, Tony Brooks said:

The red bit - I still think that points to a fuel supply problem and nothing to do with the thermostart.

The blue bits - they lend some credence to the thought the compression is low, worn engine.

However test the fuel pump deliver firstr.

Thank you again Tony, I will look into this next time I'm onboard, going home in an hour or so.

Kevin

[Kendorr]

Thanks for all the help here. I came back to boat yesterday and had a good clean around the engine and checked all the joints were tight. I noticed there was a small leakage from the join between the top copper and rubber pipe. I managed to fit another hose clip and proceeded to go through the startup procedure. It took a lot of coaxing into action!

 

I've just been out to the engine again, joint was still dry, set it to pre-heat, after 5 seconds the air filter was showing signs of smoke, after 10 seconds I heard the 'putt' noise as the manifold opened, another couple of seconds there was a nice flame briefly from under the air filter, turned the key to ignition and fired up after 2 or 3 turns of the engine :-)

 

Obviously that minor seepage from the joint was causing the pressure to drop resulting in the problems I had starting her up.

Kevin

[Tony Brooks]

I am pleased you sorted it and hope it stays OK.

I think this topic is an object lesson on the dangers of self diagnosis from limited or very limited knowledge when a good set of symptoms posted here may well point you in a different direction and save you spending unnecessary cash.

[smileypete]

In a pinch you could try warming the intake with a hairdryer:

Sometimes starting problems can be down to poor gloplug connections, a 20% volt drop loses a third of the heat output.