connecting fuel line to outboard engine

[farquart]

does there need to be fuel in the built in tank of a 4hp 2 stroke engine or can you connect straight from the gerry can.

Sorry for such a stupid question but never had an outboard before with auxillary fuel line .

 

[fergie_mac66]

im not fully understanding the question but thought that most outboards have inbuilt tank or an external . but as a suggestion put the type and model of engine up then someone will know details about the model

 

[orangemikey]

outboard fuel line

Have a look under the hood at the fuel line from the tank, most outboards have a "Y" valve somewhere in this line which changes between internal and external tank.

 

[Allan]

I have just sold a 4hp Johnson which I used with an external tank on the back of my previous boat. When I used it on the tender I used the internal tank. I didn't have to switch anything. I still have the external tank.
Allan

 

[VicS]

does there need to be fuel in the built in tank of a 4hp 2 stroke engine or can you connect straight from the gerry can.

Sorry for such a stupid question but never had an outboard before with auxillary fuel line .

What engine ? make and year ?? model number a serial number if possible too.

We may be able to point you in the direction on an owners manual, at the very least find a diagram of the fuel system.

 

[NickRobinson]

No sure if you are talking about a modification here-

Does the OB have a fuel pump (small valve body bolted to crank case) or is the fuel delivered from the internal tank by gravity?

No pump, and no way (unless provided) to lift fuel from external tank on floor. Bulb will work but will need hand pumping all the time the engine is running.

If set up for internal / external fueling, no need to have fuel in the int. tank (but not a bad idea to have a reserve- )

Nick (Rivendell)

 

[VicS]

Some outboards do have the provision to run off either an integral tank or a remote tank

A fuel pump will be fitted for the remote tank. Fuel from the integral tank may flow by gravity, it may be pumped by the same pump or there may be a separate method of delivering fuel from the integral tank.

When we know exactly what engine the Op has it will be possible to give a sensible answer.

 

[Lakesailor]

My Mariner 4hp had an internal tank and an external connector. The fuel tap had three positions. One for the internal tank and the other for the external one (and Off, of course).
Just plug in the external tank and turn the tap to "external tank" and pump the bulb until it is hard.
Tohatsu and Mercury are the same motor but may have different specs.

Tap is in the centre of the pic.

 

[VicS]

(and Off, of course)

They don't necessarily have to have an Off. Turning to the remote tank shuts of the internal tank. Disconnecting the remote tank effectively shuts that off.

 

[farquart]

My Mariner 4hp had an internal tank and an external connector. The fuel tap had three positions. One for the internal tank and the other for the external one (and Off, of course).
Just plug in the external tank and turn the tap to "external tank" and pump the bulb until it is hard.
Tohatsu and Mercury are the same motor but may have different specs.

Tap is in the centre of the pic.

cheers lakey

will have a look at the engine to see if I can find a switch

 

[farquart]

I have just sold a 4hp Johnson which I used with an external tank on the back of my previous boat. When I used it on the tender I used the internal tank. I didn't have to switch anything. I still have the external tank.
Allan

Hi Allan

had another look at the engine and it is a johnson 4hp, took the cover off cant find any switch.

connected fuel from can, pumped the fuel line till hard engine still will not start, but was in perfect working order last season.

 

[VicS]

Hi Allan

had another look at the engine and it is a johnson 4hp, took the cover off cant find any switch.

connected fuel from can, pumped the fuel line till hard engine still will not start, but was in perfect working order last season.

What year is the engine, What is the model number?

Armed with the model number we can find out about it.

Some of the small Johnson and Evinrudes have a fuel tap combined with the choke control.
Pull it to operate the choke, turn it to open the fuel tap IIRC to use the internal tank.

Did you feel it pumping fuel with the bulb or did it go hard immediately.


Do you have good sparks at the plug(s) That's the first reqirement!

 

[farquart]

What year is the engine, What is the model number?

Armed with the model number we can find out about it.

Some of the small Johnson and Evinrudes have a fuel tap combined with the choke control.
Pull it to operate the choke, turn it to open the fuel tap IIRC to use the internal tank.

Did you feel it pumping fuel with the bulb or did it go hard immediately.


Do you have good sparks at the plug(s) That's the first reqirement!

ok thanks will go and have a look engine is about 10yrs old and has had a recent service so dont think it is the plugs.

 

[VicS]

ok thanks will go and have a look engine is about 10yrs old and has had a recent service so dont think it is the plugs.

The plugs may be Ok but it does not mean the ignition system is working and producing the sparks.
Checking for good fat blue sparks is the first and easiest thing to do. If the engine has a stop button make sure that not shorting if you have no sparks. I'm pretty sure it will have CD ignition.
I'd expect it to have a stop button with a safety lanyard ... got the lanyard clipped on properly?

Going out this pm back later but Lakesailor knows these little Johnsons fairly well so he may be able to help once its positivel identified

 

[Lakesailor]

This is a 4hp (bit older) without an external fuel supply. The knob on the left turns to switch on the fuel and pulls to operate the choke.
My Brother in law has an Johnson with an external feed. I amy be able to ask him.

Point is though....You say it won't start. Does this apply to the internal tank as well?
There are plenty of reasons it won't start after winter. Try chucking a bit of fuel into the carb throat. If it fires there must be a spark. If it then stops, there is a fuel problem.

In view of the news about a woman conflagrating herself, be careful with petrol.

 

[farquart]

ok fixed it, all working now just needed a bit of choke

 

[Lakesailor]

ok fixed it, all working now just needed a bit of choke

You're very brave to post that last comment