Beta engine problem

[Crinan12]

I have had an issue with my beta 16hp 2007 engine that I can't get to the bottom of.

When the engine is cold, for the first 2 or 3 minutes it sort of 'breathes' - i think the term is 'hunting'. The revs fluctuate slightly. When the engine warms up it is fine and runs normally. I am not sure if the video shows what i mean.

Co pilot suggested that the engine is drawing air in upstream of the lift pump and when the engine is cold it takes some time to dispel the air. It said to pump the lift pump lever immediately before starting and if that cured the problem it would confirm an air leak. I tried that but it is just the same.

Any thoughts?
Thank you

 

[Crinan12]

P.s video won't upload

 

[Crinan12]

Come on forum, you have never let me down so far!!

Anyone any ideas about this

Would be very grateful for any pointers

Thanks

 

[Alex_Blackwood]

Come on forum, you have never let me down so far!!

Anyone any ideas about this

Would be very grateful for any pointers

Thanks

Why not ask Beta Here

 

[Crinan12]

Yeah I can do and they have been really helpful in past

I just prefer to ask here first, in case I can sort it that way. I guess i feel like I am bothering them !

 

[Babylon]

I agree Beta are hugely helpful.

There is also the Facebook Beta Marine Owners' Group which is a source of a lot of knowledge and experience.

 

[Boater Sam]

It may be the alternator load changing as it charges the start battery after it has discharged a bit getting the engine going.
I have had this happen when my Sterling charge controller switched the alternator on and off maximum charge rate, a sort of 4 second decrease in revs then back to idle.

 

[Sea Change]

Could be a whole load of different things. Hunting is often a sign of less than perfect fuel supply, either through a partially clogged filter or an air leak, which can appear worse when the engine is at low revs.

I like the alternator theory too.

Do you put any revs on the engine for starting? Or just leave it at idle?

 

[potentillaCO32]

Have you cracked off each injector while running to clear any air?

 

[Amlov]

My guess would be that the fuelling is set too low on the governor. My feeling is that these engines are set up with full fat diesel and run a little ‘lean’ on B7. The adjustment screw is under a tamper-proof cap and everyone will tell you that the world will end if you touch it. But, if you speak to Beta they will explain how to adjust it and even send you an information sheet detailing how to adjust the fuelling and tick over - and all without the world ending.

 

[PabloPicasso]

Sounds like a fuel problem.
Have you clean fuel, use a fuel treatment.
Are the deisel filters seated properly? Any recent maintenence on the fuel system would be a prime suspect.
Air filter part blocked?
System needs bleeding?
Some other control mechanism issue?
Cracked fuel lines, banjo bolts not seated right etc.

 

[PetiteFleur]

Make sure you have no air leaks in the delivery piping/ hose - tighten all fittings. This worked for me. Beta 25hp.

 

[Crinan12]

It may be the alternator load changing as it charges the start battery after it has discharged a bit getting the engine going.
I have had this happen when my Sterling charge controller switched the alternator on and off maximum charge rate, a sort of 4 second decrease in revs then back to idle.

I think i can count that out because it does it even when my batteries have been fully charged via a mains charger. I have 2 batteries and it happens whether I select battery 1 / 2 /Both

 

[Crinan12]

Could be a whole load of different things. Hunting is often a sign of less than perfect fuel supply, either through a partially clogged filter or an air leak, which can appear worse when the engine is at low revs.

I like the alternator theory too.

Do you put any revs on the engine for starting? Or just leave it at idle?

Key thing is that it only does it when engine is cold - maybe for first 2-3 minutes. Then runs perfectly.
I have changed both filters and my fuel is very clean - I had a new tank fitted and I filter all my fuel so I am sure it is not that.

I put some revs on to start the engine. But it starts fine in idle also.

 

[Crinan12]

Have you cracked off each injector while running to clear any air?

No - I don't know how to do that but I will look into it. Thanks.

 

[Crinan12]

My guess would be that the fuelling is set too low on the governor. My feeling is that these engines are set up with full fat diesel and run a little ‘lean’ on B7. The adjustment screw is under a tamper-proof cap and everyone will tell you that the world will end if you touch it. But, if you speak to Beta they will explain how to adjust it and even send you an information sheet detailing how to adjust the fuelling and tick over - and all without the world ending.

Thanks, I will look into this.
But why would it have run fine before and now need adjusting?

 

[Crinan12]

Sounds like a fuel problem.
Have you clean fuel, use a fuel treatment.
Are the deisel filters seated properly? Any recent maintenence on the fuel system would be a prime suspect.
Air filter part blocked?
System needs bleeding?
Some other control mechanism issue?
Cracked fuel lines, banjo bolts not seated right etc.

I am pretty sure it is nothing to do with dirty fuel - would it not run badly all the time if that was the case?
Fuel is clean and filters have been changed in any event.

 

[Babylon]

No - I don't know how to do that but I will look into it. Thanks.

Someone will be along in due course to explain how to crack off each injector to clear any air in the system (a bit like easing the bleed-screw while using the lift-pump or running the engine), but I don't see how that could be the source of your problem as it only occurs when the engine is cold.

 

[Crinan12]

Someone will be along in due course to explain how to crack off each injector to clear any air in the system (a bit like easin the bleed-screw while using the lift-pump or running the engine), but I don't see how that could be the source of your problem as it only occurs when the engine is cold.

Yeah I was hoping the fact my issue only happens for the first couple of minutes would narrow down what the problem is.

It doesn't really affect anything- I am just worried it will get worse/lead to a breakdown.

I emailed beta a few days ago but I haven't heard anything back.

Co pilot suggested a glow plug issue or air being drawn in downstream of the lift pump and then getting forced out when engine is running. It said to push the bleed lever a good few times before starting and that would expel the air - then start engine and see if it runs okay. So I have a few things to check and hopefully I can get to the bottom of it.
Thanks

 

[potentillaCO32]

Yeah I was hoping the fact my issue only happens for the first couple of minutes would narrow down what the problem is.

It doesn't really affect anything- I am just worried it will get worse/lead to a breakdown.

I emailed beta a few days ago but I haven't heard anything back.

Co pilot suggested a glow plug issue or air being drawn in downstream of the lift pump and then getting forced out when engine is running. It said to push the bleed lever a good few times before starting and that would expel the air - then start engine and see if it runs okay. So I have a few things to check and hopefully I can get to the bottom of it.
Thanks

Cracking the injectors is a normal part of bleeding a beta and air can stay in them despite running, albeit roughly. Just with a spanner undo each injector feed just half a turn for a few seconds while the engine is running until clear diesel comes out with no bubbles. Do 1 after the other.