petrol leak from fuel line on outboard??? any ideas?

[lucyboatgirl]

Hey you lot.

I just checked my petrol tank for my yamaha outboard and it had had like 10litres of petrol in it and it somehow empty. I looked at the line to the engine and it didnt look loose or anything but under the engine was filled with spilled petrol. I can only imagine that the line is leaking petrol? could this happen do you think if the cable wasn't plugged in correctly and was dripping out petrol? Or is there any other obvious and common thing that this might be with a n outboard fuel line?

Dont worry of course I know you lot cant see it but just thought there might be something obvious you could advise or a good way of finding the leak? Thanks for any help you can give me. I guess I'm probably going to have to find someone to have a look at it but just incase its easy solved.

 

Thanks for any help you can give me. thank you thank you x x x x x

[cereal tiller]

5 minutes ago, lucyboatgirl said:

Hey you lot.

I just checked my petrol tank for my yamaha outboard and it had had like 10litres of petrol in it and it somehow empty. I looked at the line to the engine and it didnt look loose or anything but under the engine was filled with spilled petrol. I can only imagine that the line is leaking petrol? could this happen do you think if the cable wasn't plugged in correctly and was dripping out petrol? Or is there any other obvious and common thing that this might be with a n outboard fuel line?

Dont worry of course I know you lot cant see it but just thought there might be something obvious you could advise or a good way of finding the leak? Thanks for any help you can give me. I guess I'm probably going to have to find someone to have a look at it but just incase its easy solved.

 

Thanks for any help you can give me. thank you thank you x x x x x

Is the fuel tank sited higher than the Engine,meaning is the base of the Tank sitting higher than lower edge of the removable engine cover?

[lucyboatgirl]

hi cereal tiller, Yes it is!!!! The fuel tank is on the roof! Is this bad? in my boat safety certificate the inspector wasnt happy with the fuel tank being inside in an enclosed space. Could this be the problem?

 

thanks

[Phil Ambrose]

At a guess I would say that with the tank on the roof it has too much head and is just gravity feeding out of the carb. Check all fuel lines for tight see and turn fuel off when not running

The examiner was quite right about the location of the remote tank, you should be able to knock up a bracket fixed to the transom to accept the remote tank.

Phil 

[cereal tiller]

27 minutes ago, Phil Ambrose said:

At a guess I would say that with the tank on the roof it has too much head and is just gravity feeding out of the carb. Check all fuel lines for tight see and turn fuel off when not running

The examiner was quite right about the location of the remote tank, you should be able to knock up a bracket fixed to the transom to accept the remote tank.

Phil 

Wot Phil said ,and petrol vapour is heavier than Air so will collect and present a Fire/Explosion hazard so best not Kept in the Boat's Cockpit or Accomodation. Portable Outboard Fuel tanks have a Vent which is usually closed for carrying or when the Boat is not in use.The Vent is usually open when the Boat is under way .it will emit Vapour when agitated or when Ambient Temperature rises 

[Sea Dog]

Just a little wander off topic for safety reasons....

Do make sure your petrol is outside the 'enclosed space', but also remember that petrol vapour is invisible and heavier than air. This means that you should site your tank where anything leaking from it will go overboard rather than there be any chance of it finding it's way to low level in the confines of the boat - where it will be trapped and lurk menacingley, silently awaiting a spark or naked flame. Everywhere on the boat is below the roof, so that would possibly not be a preferred location. As Phil suggests above, on the transom - outboard side - is probably the most sensible choice. 

Now go back 'on topic' to finding what's wrong... but do think very carefully about that vapour thing, ok?

 

+1 for Cereal's comment too - our posts arrived simultaneously! 

Edited October 9, 2017 by Sea Dog
+1

[forsberg]

Hi there!

An outboard will almost always leak some petrol, it should not but does. The carburator needle valve is sensitive to dirt and it ages with time, this is the most common cause.

Does your engine have a good fuel filter? A leaking needle valve will also affect engine performance

The hose and hand pump eventually starts to leak. Both can be fixed ( and should be ) but you can never trust it .

The fuelline should always be disconnected  when not in use if the tank is above the engine. prefably at the tank.

Closing the airvent on the tank makes it more difficult for the petrol to spill out as there will be a vaccum in the tank, and it should normally be closed when not in use.

Unfortunally with the tank on the roof if you close the airvent, as it gets hotter in the day pressure will build up and eventually the needle valve might be forced open.

Installing an approved fuel switch at the tank might be the best way to prevent further large spillages.

[lucyboatgirl]

OK that is all really really helpful. 

thanks for the safety advice seadog and cerealtiller. Not off topic at all. Very good info for me to know. I think where my fuel tank is is the safest place for it. I dont think there is space on the transom to build a shelf for it phil but thanks for the advice.

I am sorry for my lack of technical knowledge. i know nothing about my engine. I have never checked the fuel filter and i dont know how. i dont know what a needle valve is?

I have had the boat for a year and a half and the tank didnt leak. But the last two tanks i have filled up have been gone the next time i went to start the engine. (very expensive mistake). Could this have come just from the tank being up high and me forgetting to close the air vent? (i defo forgot to close the airvent the last two times i lost petrol) and then the petrol seems to have leaked out from where the fuel line connects to the engine. would this be where you would expect to see a leak?

My solution is going to be to start disconnecting the fuel line at the tank when not in use. But i think i'll have to get a friend to have a look. But thank you so much for all your help folks. Especially the safety advice about the vapour. VEry helpful.

Hope yous all have a diesel good day out there x x x x

 

[Tony Brooks]

losing the air vent would build up a vacuum in the tank as petrol leaked out of the carburettor and thus stopped any further leak.

The fuel line probably connects to a fuel pump at the engine end. It probably has a diaphragm in it and if that splits or the pump body bolts loosen it may well leak but not right where the hose fits onto the engine but close by. On may outboards the fuel  hose has a bayonet fitting so you can remove the hose from the engine. If its leaking from here it is either not fitted properly or an O ring is worn. However leaks from there tend to drop onto the boat or water and not sit in the tray the outboard cover clips onto.

I think this needs lots of cleaning with kitchen towel so you can see exactly what bit gets wet with petrol first.

If you follow the fuel hose run into the engine the first chunk of metal it runs to after any bayonet fitting is usually the fuel pump. Another hose runs from there to another, often silvery, chunk of metal parts with a a moving part on it related to the throttle. This is the carburettor. It is important that the fuel level inside is kept at a constant level so it can measure the correct amount of petrol to supply to the engine. This is done by a plastic or metal float inside the carburettor floating on the petrol. This opens and closes a valve that lets petrol into the chamber when its required. That valve is called a needle valve.

If the float is punctured or if the seating of the valve is failing you will get leaks from the carburettor into the pan under the engine block.

If you can dry the leaking petrol so you can find out where it is leaking from and then post a photo we may be able to tell you how to cure it. If it is a pump diaphragm, float or needle valve I fear you will probably have to pay a professional to sort it. The carburettor may need adjusting afterwards.

There may be a locker to one side of the engine that is either fully fibre glassed on all surfaces or haas a metal gas tank type thing it it. In either case it would need a decent sized vent overboard. The fuel tank could go there.

 

[lucyboatgirl]

Wow thanks so much Tony, really detailed and helpful advice. its a bit tricky for me to follow saying as i dont know anything about engines. I have pretty much found the drip. the engine still runs fine but when its running the dripping gets really fast drip drip drip drip and i can see it falling into the tray that the engine is bolted onto. Im pretty much convinced the leak is coming from where the fuel line connects onto the engine. I have taken a photo of the socket that the fuel line plugs into. Am i correct in thinking that the socket on the right is the needle valve? leading to the carburetor? (apologies for my ignorance ha ha but im trying to learn) Is it normal for the metal pin in the needle valve to slump down like that? or should it be dead center? could this be my problem? Or is it more likely to be some damage to the fuel line plug? Because i guess if it is the needle valve then i need a mechanic and if its the fuel hose i can just buy another one.

I know i am asking you to try to diagnose my fuel leak from a photo which is pretty much impossible i would think but just any pointers or advice would help me out as to my next step. Thanks again for all your help and patience with a total newbie.

thank you x x x x xx

[Tony Brooks]

No, the needle valve is some where else.

The photo is too close up to get a full view it I think it is of the fuel line connector on the OUTSIDE of the engine.

Your use of the term "tray" is probably not helping me much.

Outboards usually have a top cover that makes them look smooth but will easily lift right off the engine so you can see the parts under it. You often have to undo a couple of clips at the side or lift a catch in the centre at the top or at the back/front.  It probably has the make and model marked on it.

When its in place it sits and is clipped onto the tray that the engine proper is sandwiching between itself and the leg that goes into the water. Your photo seems to show the front outside of that tray. This is exactly where I would expect the main fuel line to clip onto the engine but it can not drip into the engine tray.

The think you have a sort of well at the back of the boat with the extreme back of that well forming the up stand (the transom)  the outboard is bolted to. That is part of the boat and not the engine but I can see why you might be calling that bit a "tray". It looks a bit like one with three taller sides and one lower side. A fuel leak from the main fuel line connector would drip into this part but normally the fumes would simply fall over the part the outboard is bolted to long before they got into the boat. However wind may well change that so a leak here is still bad news.

I think the brass bit is the actual fuel connection and the silver bit the part a catch on the connector clips onto. AS there is no "rubber" O ring around the brass bit it must be in the corresponding hole in the connector on the end of the fuel line.

If the above makes sense and is correct my guess is one of the following:

1. You have taken the fuel line off the engine and its not back on properly.

2. For some reason the fuel line routing has been moved and the hose is pulling the connector up/down/to one side.

3. The O ring is worn but you may have to buy a new hose assembly to get a new one. You might need to talk to the agent for those outboards.

 

Edited October 11, 2017 by Tony Brooks

[lucyboatgirl]

hey tony, 

yes you are completely right the 'tray' im referring to is the transom. and you are completely right that this is  a picture of the socket on the engine with the fuel line disconnected. I'm gonna go back to my boat and remove the cover of my engine and have a look. I think i need to try to find a mechanic that might come and have a look at it for mates rates because i have got no money ha ha. but thank you so much for your help. I have at least narrowed it down and at best learned a little bit about my engine.

 

thanks for your help.

x x x x x

[Tony Brooks]

Before doing anything more take the fuel line off and put it back with a good shove. It won't do any harm and just might cure the leak.

That connection will drip for a while when you disconnect it but should stop when any petrol in the  hoses inside the to cover has drained out.

[cereal tiller]

1 hour ago, lucyboatgirl said:

Wow thanks so much Tony, really detailed and helpful advice. its a bit tricky for me to follow saying as i dont know anything about engines. I have pretty much found the drip. the engine still runs fine but when its running the dripping gets really fast drip drip drip drip and i can see it falling into the tray that the engine is bolted onto. Im pretty much convinced the leak is coming from where the fuel line connects onto the engine. I have taken a photo of the socket that the fuel line plugs into. Am i correct in thinking that the socket on the right is the needle valve? leading to the carburetor? (apologies for my ignorance ha ha but im trying to learn) Is it normal for the metal pin in the needle valve to slump down like that? or should it be dead center? could this be my problem? Or is it more likely to be some damage to the fuel line plug? Because i guess if it is the needle valve then i need a mechanic and if its the fuel hose i can just buy another one.

I know i am asking you to try to diagnose my fuel leak from a photo which is pretty much impossible i would think but just any pointers or advice would help me out as to my next step. Thanks again for all your help and patience with a total newbie.

thank you x x x x xx

Yes, that metal Pin should be Central and be Spring loaded so maybe the Engine Connection is at fault.when the Pin is pressed in Fuel is allowed to Flow.

Give it a wiggle and test for Spring resistance, it is likely not allowing the Fuel line to Engage properly, hence the leak

E.T.A. the pin should be fixed, it is not spring loaded, it displaces a Ball in the Line Connector to release fuel

Edited October 11, 2017 by cereal tiller

[Bricksh]

Also worth mentioning I think. With increasing amounts of ethanol in petrol nowadays older rubber fuel lines/o rings etc will perish and need replacement. I have just had to change all the fuel lines on a 1978 camper van. Even R9 fuel hose is susceptible but ethanol resistant lines are available if you look from the likes of AFS.

[Tony Brooks]

1 hour ago, cereal tiller said:

Yes, that metal Pin should be Central and be Spring loaded so maybe the Engine Connection is at fault.when the Pin is pressed in Fuel is allowed to Flow.

Give it a wiggle and test for Spring resistance, it is likely not allowing the Fuel line to Engage properly, hence the leak

E.T.A. the pin should be fixed, it is not spring loaded, it displaces a Ball in the Line Connector to release fuel

Very well spotted.

[WotEver]

3 hours ago, cereal tiller said:

Yes, that metal Pin should be Central and <snip> the pin should be fixed, it is not spring loaded, it displaces a Ball in the Line Connector to release fuel

So... it means a mechanic by the looks of it, to replace or repair that fitment. 

[Tony Brooks]

Unless the pin is just bent in which case very careful use of a screwdriver as a leaver might get it straight enough to work, however Idon't see how you can get the connector one with it like that unless its floating about.

[WotEver]

4 hours ago, Tony Brooks said:

Unless the pin is just bent in which case very careful use of a screwdriver as a leaver might get it straight enough to work, however Idon't see how you can get the connector one with it like that unless its floating about.

The dripping suggests to me that the end of the fuel hose is now damaged (valve permanently open) and it never fits properly. So two things to address - connector at engine end plus probably the fuel hose. 

[Tony Brooks]

But if the fuel hose was clipped in place the O ring in the fitting should seal the connection unless the pin stops it going fully home and square. I think it only drips when connected and when the air vent screw in the tank is not closed. I don't think it drips when disconnected.