Vetus engine losing power

[Stuart Lewis]

Hi.

I am having an on-going issue with my Vetus M414 engine losing power and being unable to rev above about 1500rpm.

It will idle fine and run at tickover in gear for a couple of hours quite happily, but within 10-15 minutes of running at 4mph cruising speed, around 2400rpm it will start to coughs bit and then lose power. dropping to neutral it will then run very roughly for a few minutes before picking up again.

It is behaving as if it has run out of fuel, but my tanks are full (I have checked)..

 

I have found that bleeding the filter whilst still running the engine, both in gear and at idle, will restore the power, but obviosuly this isn't right or indeed safe especially as it always does it in locks and at swing bridges.

 

I initially suspected an air leak into the fuel system, but having replaced a number of suspect pipes and copper washers it still does it. I have also wrapped every possible joint in grease and I am now sure there is no air ingress.

 

So I have turned my thoughts towards either the electric fuel pump, which is only 2 months old, but isn't as quiet as I would have expected it to be, it makes quite a loud clicking noise, or I have also wondered if the pressure release valve between the bottom of the filter and the return line maybe at fault and not retaining the correct pressure within the system and therefore not allowing enough fuel up into the high pressure pump and instead returning much of the fuel straight back to the tank.

 

Any thoughts would be most gratefully appreciated as this is really winding me up now and spoiling many weekend cruises.

 

Generally the engine sounds as sweet as anything, no smoke to speak of and indeed it managed to tow a broken down vessel 12 miles back to our marina, all be it fairly slowly, so I know there is nothing mechanically major wrong.

 

Thanks

 

 

[kevinl]

The fuel tank must have an air inlet, if this is blocked it would create a partial vacuum in the fuel tank when fuel gets sucked out, if it's blocked it could give this kind of effect, long shot but try running with the filler cap off see if it still does it, as I say long shot but it's free to do so nothing lost.

K

 

CWDF pedantry requires I tell you that it's Scarisbrick , I feel so much better now

Edited September 24, 2014 by kevinl

[bigste]

I know nothing about vetus but I think you must be getting warm when you mention fuel pump.

[Tony Brooks]

I am intrigued by this pressure release valve at the bottom of the filter? The bottom is where all the crud and any water collects so there is no way any from of return should be there. This sounds like misidentification or a misdescription to me but if its correct it sounds like an "owner type" modification.

 

Do you have any primary filter/water trap in your system before the fuel pump? You can not rely upon the idiot filter in the end of the electric pump under the bayonet cap. If not there is a chance the original pump change problem was caused by dirt/bug blocking the valves in the pump and its done it to the new pump now. I would go with checking the tank breather first and then think about rigging a temporary fuel supply gravity fed to the main filter to see if that cures it.

 

If the inlet to the fuel system in the tank becomes blocked then the lift pump will create a vacuum in the pipe after a while and that is much more likely to suck air into the system. Try blowing back into the tank - after you have made sure the breather is clear.

 

I am intrigued by the PRV, any chance of a photo?

[Stuart Lewis]

Ahhh Okay, sorry, to clarify, PRV isn't connected to the bottom of the filter. I'll try and get a photo posted later. But I'll explain the sequence of our fuel line.

Tank pickup - stopcock - electric pump - IN CAV filter - OUT CAV filter - high pressure pump - Injectors - leak-off rail - return feed - tank.

Now, where the OUT pipe enters the high pressure pump, it is connected via a banjo closest to the pump, then working away, a PRV, then a T union connecting it up to the fuel return

Hope that clarifies it a little better??

[nicknorman]

Clearly air is getting in somewhere. Some good suggestions already, but I wonder how the fuel is extracted from the tank? Having an electric lift pump suggests a tank at the bottom of the boat with the possibility of a top exit for the fuel. If this is correct it would mean a pipe inside the tank from the top to the actual point of fuel inlet, near the bottom. This pipe might only be supported at the top and there is a slight possibility that vibration could cause it to crack near the top fitting, thus allowing air in. Improbable, so check everything else first.

[Stuart Lewis]

Tanks above engine. Originally the fuel line went down to a mech lift pump, but for whatever reason before I got it, this was taken out of the loop and an electric one used.

[RLWP]

This seems highly unlikely but... You say tanks plural. Is the tank that the engine is connected to the one with the filler? I'm wondering if by some bizzare method, one tank is full and the other almost empty, or perhaps filling slowly via a blocked balance pipe

 

Richard

Tanks above engine. Originally the fuel line went down to a mech lift pump, but for whatever reason before I got it, this was taken out of the loop and an electric one used.

 

Probably because the engine showed weird behaviour like you are experiencing. Replacing the mechanical pump with an electric one is a common knee-jerk reaction

 

Richard

[nicknorman]

This seems highly unlikely but... You say tanks plural. Is the tank that the engine is connected to the one with the filler? I'm wondering if by some bizzare method, one tank is full and the other almost empty, or perhaps filling slowly via a blocked balance pipe

 

Richard

 

 

Probably because the engine showed weird behaviour like you are experiencing. Replacing the mechanical pump with an electric one is a common knee-jerk reaction

 

Richard

Tanks as in tank's?

[RLWP]

 

It is behaving as if it has run out of fuel, but my tanks are full (I have checked)..

 

 

 

Tanks as in tank's?

 

No

 

Richard

[Stuart Lewis]

Yes tanks, one either side, the engine is connected to the one with the filler, but I have drained and filtered all the fuel (around 160 litres) and am certain the balance pipe is okay

[RLWP]

And if you take the pipe off the inlet to the low pressure pump, fuel pours out?

 

To be honest, if you can fix the problem by bleeding the filter, you've got an air leak.

 

Richard

[p6rob]

I had a similar sounding problem recently. There was a lump of silicone sealant restricting the fuel pick up pipe. The symptoms were exactly as you describe although my engine is a BMC and has a mechanical fuel pump.

I'm not saying you'll also find a lump of silicone, but I'd check the pipes from the fuel tank to pump is clear and unrestricted and if you can, blow into the tank outlet to check the pickup pipe is clear too.

 

Rob

[Schipper]

Is the electric pump fitted horizontal ? and has it got a colour sticker on the body ?

 

 

 

Geert

[bizzard]

You can eliminate the main fuel line and tanks by removing the electric pumps inlet pipe and fixing up temporary tube to it somehow and draw fuel from a can of fresh diesel fuel instead to see how it runs.

[Guest]

My vetus 415 has an electric fuel pump. In the end of this is a tiny filter which causes many Vetus engines to stop (so an RCR man told me), as many owners are unaware of it and don't change it. The problems reported are similar to those here. Could this electric pump have such a filter? Mine unfastens as per the arrow in a manner similar to a bayonet cap light bulb (17mm spanner IIRC)

 

Edited September 25, 2014 by Guest

[Tony Brooks]

Tanks above engine. Originally the fuel line went down to a mech lift pump, but for whatever reason before I got it, this was taken out of the loop and an electric one used.

 

Right, so this may or may not be the standard Vetus type lift plump. If it is cylindrical, maybe about 5" long with a hexagon and bayonet cap it the normal Vetus type with the filter in the end under the bayonet cap. If the body is more rectangular then it is probably an after-market Facit type pump and I have had those fail because of dirty fuel (probably blocked valves).

 

Your description of the fuel run does not seem to show a primary filter or water trap so there is nothing stopping dirt getting into the lift pump. However I do not think I can recall seeing a Vetus with a CAV type filter. I think they were all spin-on ones. Must be a very old engine and maybe not Mitsubishi based.

 

That two of us who have suggested a gravity fed test rig to the inlet of the main fuel filter bypassing the tank & pump.

 

Traditionally the fuel inlet in the tank would be fitted with a course screen or strainer. These can become bocked over time and if so could well cause your symptoms.

[jonk]

Hi.

I am having an on-going issue with my Vetus M414 engine losing power and being unable to rev above about 1500rpm.

It will idle fine and run at tickover in gear for a couple of hours quite happily, but within 10-15 minutes of running at 4mph cruising speed, around 2400rpm it will start to coughs bit and then lose power. dropping to neutral it will then run very roughly for a few minutes before picking up again.

It is behaving as if it has run out of fuel, but my tanks are full (I have checked)..

 

I have found that bleeding the filter whilst still running the engine, both in gear and at idle, will restore the power, but obviosuly this isn't right or indeed safe especially as it always does it in locks and at swing bridges.

 

I initially suspected an air leak into the fuel system, but having replaced a number of suspect pipes and copper washers it still does it. I have also wrapped every possible joint in grease and I am now sure there is no air ingress.

 

So I have turned my thoughts towards either the electric fuel pump, which is only 2 months old, but isn't as quiet as I would have expected it to be, it makes quite a loud clicking noise, or I have also wondered if the pressure release valve between the bottom of the filter and the return line maybe at fault and not retaining the correct pressure within the system and therefore not allowing enough fuel up into the high pressure pump and instead returning much of the fuel straight back to the tank.

 

Any thoughts would be most gratefully appreciated as this is really winding me up now and spoiling many weekend cruises.

 

Generally the engine sounds as sweet as anything, no smoke to speak of and indeed it managed to tow a broken down vessel 12 miles back to our marina, all be it fairly slowly, so I know there is nothing mechanically major wrong.

 

Thanks

 

 

Hi, I had a similar problem a couple of years back. In my case one of the filters was clogged - there are THREE fuel filters and one of them is often overlooked in services apparently. At tickover all was well but at higher revs it would be ok for a while and then die down to tickover, after a while the revs could be increased again and then it would die again after a short while etc. Might be worth looking at?

 

John

[Stuart Lewis]

It is an old Vetus, circa 1987, Mitsubishi S4L base.

The pump is a rectangular facet type, 4-6 psi, unfiltered.

 

Only filter is a CAV mounted on engine above high pressure pump.

 

I am fairly certain the tank breather is clear as fuel came out of it when filling up last time.

 

Does the positioning of the pump have any bearing on things, it is currently just below bottom of tank, level with top of engine.

The fuel pickup is located on top of the tank, it loops up and then down to pump.

Hi, I had a similar problem a couple of years back. In my case one of the filters was clogged - there are THREE fuel filters

Can you remember where were those filters are located, as I say I have only found one, but the fuel system seems to have been altered a little from original.

[nicknorman]

If the fuel pickup is on top of the tank, my original point about the possibility of a fractured pipe inside the tank stands, albeit other things such as the pump sucking in air are more probable.

[Schipper]

The rectangular Facet pump you got is,as Tony discribes very vulnerable to dirt in fuel,so primary filter is required.

Also,capacity for this type of pump is insuficient for a fuel system with fuel return.

The positioning of the pump is important,if the difference in height between the top of the tank and your pickup on the pump exceeds 50Cm.

I advise you to replace your pump for a cylindrical type (suitable for diesel!) and a primary filter/water trap.

 

Geert

[RLWP]

I advise you to replace your pump for a cylindrical type (suitable for diesel!) and a primary filter/water trap.

 

Geert

 

I would advise going back to the original mechanical pump

 

Richard

[Tony Brooks]

Although in theory the filter should be under a positive pressure when the engine is running I would be bit wary about the sealing on the centre bolt holding the CAV filter together. Originally the top of the part with the pipes connected to it had a flat machined around the bolt hole and a soft washer was used to seal it. Later models had a small taper around the top of the hole and an O ring around the bolt. It seems some O rings supplied with pattern filter elements are too small so do not seal properly. I always fit a soft washer under the head bolt and then the O ring on later models.

 

I don't think you have three filters. I believe Jonk is talking about a later engine with an in initial water trap/filter and in this case the third filter is the one in the end of the Vetus supplied cylindrical lift pump. I think you only have one filter, the CAV one.

 

You have to isolate the fault area.

 

1. Try to rig a gravity fed test system direct to the filter.

 

If that solves the problem try using a car spare wheel with the tyre blown right up as an air source to blow back into the fuel pick up pipe. You will need a length of plastic hose, probably some "bodge tape" and take the tyre valve out. If that cures it then it is probably dirt in the tank blocking the intake.

[jonk]

It is an old Vetus, circa 1987, Mitsubishi S4L base.

The pump is a rectangular facet type, 4-6 psi, unfiltered.

 

Only filter is a CAV mounted on engine above high pressure pump.

 

I am fairly certain the tank breather is clear as fuel came out of it when filling up last time.

 

Does the positioning of the pump have any bearing on things, it is currently just below bottom of tank, level with top of engine.

The fuel pickup is located on top of the tank, it loops up and then down to pump.

 

Can you remember where were those filters are located, as I say I have only found one, but the fuel system seems to have been altered a little from original.

Sorry, the mechanic who fixed it for me told me about the 3 filters and that the one seems to be often overlooked (it was choked) but I cannot now remember which and where. I believe it is the last one in the line though. My engine is the 4.14 of about 2005 so this might not apply to you anyway but the symptoms sounded familiar.

 

John

[Tony Brooks]

Hi Jonk

 

Almost certainly the one in the end of the electric lift pump under the bayonet cap. That would be the middle one and when Vetus first fitted those pumps it was very common for engineers not to know about that filter.

 

I agree the symptoms would sound similar because the blocked filter would have casued fuel starvations and caused something of a "vacuum" in the pump.