Beta 43 getting air into system

[Keeping Up]

I have a 2-year old Beta 43 which usually starts instantly and runs perfectly. However I have found that if I leave it for more than a week or so with a half-empty fuel tank it refuses to start unless I pump the priming button on top of the fuel filter. It seems to me that air must be getting in at a high point of the system so that the fuel can drain back into the tank, but I'm wondering if anyone else has had this problem and found the cause. Possibilities that have include an air leak in the filter assembly including the pump mechanism on the top (but shouldn't the main lift pump valves prevent run-back from this) and back-feeding from the leak-off pipe (but wouldn't that need an injector pump to be faulty as well). I haven't found any sign of a diesel leak when either running or static (Beta technical were very sympathetic but could only suggest looking harder). obviously the easiest solution is to keep the tank topped up, as I usually do, but does anyone have any other ideas?

[Old Son]

My 'air entering the fuel system' on a Beta 43 was due to one of the copper feed pipes loose in it's fitting. The nut was very tight but the pipe running through the nut with the olive on the end of it was slightly loose. It took ages to find!!

[Sea Dog]

If you can rule out air getting in as suggested above, it sounds like an installation issue to me. I and very many others have a Beta 43 with no such issues, so I don't think this is a common fault. Since it seems tank level dependent and you've ruled out any leaks (although air in won't necessarily show as diesel out), I'd be looking for the supply going uphill where it shouldn't. If the fuel tank and the engine are in the usual places, maybe the pre filter assy is badly sited or the route of the fuel pipework is poorly chosen. The Beta installation manual is available free from their website, so you could check your installation against their recommendations.

 

Hopefully Tony Brooks will be along shortly to bring his expertise to bear.

 

 

 

 

Edited to flow better with the previous suggestion.

Edited October 13, 2016 by Sea Dog

[bizzard]

Could be a perforated dip tube pipe in the tank which draws in air when the fuel level drops down to that level,''not unknown.'' Unless the fuel take off is at the bottom of the tank of course.

[ditchcrawler]

The did have a problem with faulty fuel filter head castings, I have known of at least 3 which let air in.

[nicknorman]

Yes most likely cause is air getting in at the manual pump atop the filter. Ours had this problem from new but because we also had an electric lift pump the symptom was it would fire up then cut out, a couple of times, after which it would be fine. Or if I left the ignition/lift pump on for 20 secs before trying to start it would be fine. I'd try to get a new filter housing under warranty.

Edited October 13, 2016 by nicknorman

[Barry]

My 'air entering the fuel system' on a Beta 43 was due to one of the copper feed pipes loose in it's fitting. The nut was very tight but the pipe running through the nut with the olive on the end of it was slightly loose. It took ages to find!!

 

Yep.

 

Lemontoes has the smaller Beta engine. Her symptoms presented as engine running fine for about a day and half (long days' cruising) but then would begin to falter until it stopped.

 

Removing the vent from the top of the secondary fuel filter housing would show no fuel as far as could be seen above the filter. Twiddling the manual fuel priming pump would fill the filter again. Engine would start immediately and run for another day day and a half.

 

I suspected a problem with the primary fuel filter and checked it by connecting the fuel pipe into the filter directly to the fuel pipe out of the filter - thus bypassing the filter completely. Result - no air leak problems.

 

Took the primary fuel filter out, changed all the seals, cleaned all the threaded connections and gave it all a good coat of looking at. There is a third connection on that primary filter that supplies fuel to the (unused for several years) Mikuni heater.

 

Close examination revealed a brass olive on a small diameter (3/16ths) copper pipe. That olive was distorted, the pipe was deformed under the olive to the point it was waisted and, this was the clincher, the olive moved slightly on the pipe.

 

I got a new copper olive, chopped the last half inch of deformed pipe off, and reinstalled it......No more air ingress.

[Bee]

I would start looking at the bleed screw on the filter, the one on the engine that is, its unlikely to leak fuel out but might suck air in, same goes for any other filter as well, apart from that its any other joint anywhere, my installation is not too brilliant and is difficult to bleed but so far, so good.

[Tony Brooks]

 

Hopefully Tony Brooks will be along shortly to bring his expertise to bear.

 

 

Don't bring me into it! I am with Biz, Brian, and Nick as being the likely causes. As most narrow boats have a tank all but higher than the engine I would think a slightly loose pipe less likely. Much depends upon the OP's boats design and what his engine is equipped with. I do not think that all have that diaphragm priming pump on the filter for example.

[Keeping Up]

The setup is that the engine is under the cruiser stern deck and the fuel tank is at the stern (fairly conventional arrangement). The bottom of the fuel tank is roughly level with half way up the engine, likewise the top of the engine is roughly level with half way up the tank. The fuel take-off pipe starts near the bottom of the tank then rises to the top where it loops down to exit the tank from a fitting near the bottom (rather unusual there). The pipe continues (after a stop tap) with a slight downward slope to the primary filter/separator which is entirely below the level of the bottom of the tank. A flexible pipe runs down to the engine connection.

 

My own logic, which may of course be faulty, is that none of this could cause the problem because it is all below the level of the fuel and there are no symptoms of air entry when the engine is running. Similarly I can't see that Beta's suggestion of a blocked pipe or filter could be relevant. When the tank is half full the only parts of the system above the level of the fuel are the fuel filter (complete with the diaphragm priming pump in the top) and the injector/leak-off assembly; so these are my favourite culprits. Surely the fuel wouldn't run back through the lift pump though? Beta's suggestion that I buy a new lift pump to see if that makes any difference, doesn't sound too attractive to me.

 

What do people think about the suggestion from one boatyard, that fuel could syphon back through the whole system with air being admitted via the leak off pipe, the fuel passing backwards through both the injection and lift pumps? I admit I hadn't thought about the possibility of a hole in the take-off pipe inside the tank but I can't quite see how it could cause these symptoms without causing worse problems when the engine is running hard.

[nicknorman]

I think the lift pump doesn't have that good a seal for returning fluid, well that must have been the case with our one. As I said, we had similar symptoms to you and a new filter head /manual pump fixed it. They seem to be a known issue to everyone except Beta! Isn't the warranty still "valid" at 2 years?

 

If your engine is the same as ours there is a small valve with a knob where the pipe from the filter joins the injector pump, it's the air bleed valve that links to the bleed-off pipes. We leave ours open but when I had the problems it was one thing Beta suggested - close it once the engine is fully bled. Didn't make any difference when we had the problem but might be worth you trying closing it (presuming it's open).

 

Going back to the manual pump, is there any trace of diesel around its base when the engine has been running? There shouldn't be!

Edited October 13, 2016 by nicknorman

[Sea Dog]

Don't bring me into it! I am with Biz, Brian, and Nick as being the likely causes.

Well, ok Tony, I can can understand why you think it's probably those three that are the likely cause, but I'm not sure you should be naming and shaming!

[bizzard]

Count me out, I've never been anywhere near it.

[Tony Brooks]

Count me out, I've never been anywhere near it.

 

No, but you came up with a perfectly valid reason (in my opinion, as did the other two.

 

 

[Keeping Up]

I think the lift pump doesn't have that good a seal for returning fluid, well that must have been the case with our one. As I said, we had similar symptoms to you and a new filter head /manual pump fixed it. They seem to be a known issue to everyone except Beta! Isn't the warranty still "valid" at 2 years?

If your engine is the same as ours there is a small valve with a knob where the pipe from the filter joins the injector pump, it's the air bleed valve that links to the bleed-off pipes. We leave ours open but when I had the problems it was one thing Beta suggested - close it once the engine is fully bled. Didn't make any difference when we had the problem but might be worth you trying closing it (presuming it's open).

Going back to the manual pump, is there any trace of diesel around its base when the engine has been running? There shouldn't be!

Thanks I'll have a look for that air bleed valve. I haven't noticed any diesel around the pump but I'll try looking for it. Unfortunately the boat will be in for hull repairs until nearly Xmas so I won't get much opportunity to look for the problem for a while.

[Machpoint005]

>>> Beta technical were very sympathetic but could only suggest looking harder <<<

 

I think that might be a polite way of saying "it isn't a problem with the engine, it's an incorrect installation".

[Keeping Up]

I think that might be a polite way of saying "it isn't a problem with the engine, it's an incorrect installation".

 

Yes they would say that, wouldn't they, but they couldn't say what might be wrong with the installation.

[Sea Dog]

Well, ok Tony, I can can understand why you think it's probably those three that are the likely cause, but I'm not sure you should be naming and shaming!

Count me out, I've never been anywhere near it.

No, but you came up with a perfectly valid reason (in my opinion, as did the other two.

 

I was, of course, joking gentlemen (lest anyone should think that I was casting nasturtiums upon 3 of our most valuable contributors)! Can't be too careful in these sensitive times, eh?

[ditchcrawler]

 

I was, of course, joking gentlemen (lest anyone should think that I was casting nasturtiums upon 3 of our most valuable contributors)! Can't be too careful in these sensitive times, eh?

I saw the phunny side