Outboard runs, dies, runs, dies..

Salty John

Salty John

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www.saltyjohn.co.uk
Honda BF8, 4 stroke outboard. Ran fine but then, after not being run for three months, runs rough. It starts, idles somewhat roughly, dies after a few minutes. Under load it will run for a couple of minutes, then dies. Restarts easily - one pull - but then runs a couple of minutes and dies.
I suspect a gunged up carburettor. Before I strip it and clean it, any other suggestions?
It has a new fuel hose, about twice the length of it's old one, about 3' - could this be a factor? Obviously I've checked that the tank vent is open.

All suggestions gratefully received.
 
Salty John said:
Honda BF8, 4 stroke outboard. Ran fine but then, after not being run for three months, runs rough. It starts, idles somewhat roughly, dies after a few minutes. Under load it will run for a couple of minutes, then dies. Restarts easily - one pull - but then runs a couple of minutes and dies.
I suspect a gunged up carburettor. Before I strip it and clean it, any other suggestions?
It has a new fuel hose, about twice the length of it's old one, about 3' - could this be a factor? Obviously I've checked that the tank vent is open.

All suggestions gratefully received.
Click to expand...

My boat on windermere used to have a Honda 4 stroke, every time we went up there it used do exactly this.

It was always goo in the jets (idle jet esp) from evaporated petrol as you suspect already.

I eventually figured out that running it dry with the fuel tap turned off solved the problem.

It could be the float or needle, vacuum in the tank (EDIT: sorry, you checked that) or collapsed fuel pipe, stuck choke if it has one.
 
Running for a couple of minutes or so and then dying is consitent with a fuel flow problem.

Before tearing into the carb:
Check the tank vent ... wil it run OK with the cap off ?

Will it run if the bulb its pumped ... if so suspect the fuel pump or air ingress at the fuel connector.
And if the hose twixt pump and carb (if they are separate) is disconnected do you get a spurt of fuel when the engine is cranked ?

The fuel line length should not be a problem ... mine is at least that long.
 
Thanks all.

Checked and cleaned out fuel tank vent, drained carb, cleaned filter and had a general play around. Started up first pull and runs like a sewing machine once again!
 
Claymore, you have returned! I thought you had emigrated to the land of wind power generation, odd fish dishes and stylish bathroom hardware.

No, it's a Honda, it will never need replacing.
 
Having had a Seagull for 30 years I replaced it 5 years ago with a Suzuki 2 stroke, which had exactly the same "white gel" problem, which occurs with lead free petrol which is aged. At the time I was advised to ensure that it was filled with fresh fuel. I have since discovered that if I filter the fuel through a fine sieve funnel that all the gel like materials is retained and the fuel works fine. The second trick is to turn off the outboard so that the carb float chamber is essentially empty by running until the engine stops. Last 3 years no problems at all. Still wish Seagull could have produced an engine half the weight!
 
If its only a few years old it might have an oil level switch. I had the same symptoms with my Mariner. If it wasn't topped up to the max, the susequent level drop when running was enough to trigger the cut out. All done for the right reasons of course, but still annoying when it happens. I had exactly the same with a gererator.
 
Salty John said:
Honda BF8, 4 stroke outboard. Ran fine but then, after not being run for three months, runs rough. It starts, idles somewhat roughly, dies after a few minutes. Under load it will run for a couple of minutes, then dies. Restarts easily - one pull - but then runs a couple of minutes and dies.
I suspect a gunged up carburettor. Before I strip it and clean it, any other suggestions?
It has a new fuel hose, about twice the length of it's old one, about 3' - could this be a factor? Obviously I've checked that the tank vent is open.

All suggestions gratefully received.
Click to expand...

Glad to see you are sorted but here is an anecdote for others who may suffer similarly

Had a similar problem recently and took a short cut by only cleaning the carb/jet and all appeared OK until a couple of weeks later when I put it on the dinghy to go out to my moorings- same old problem as you describe.

So, back to base- this time removed fuel, cleaned tank, ditto with all fuel lines, fuel tap and the carb once again, filled up with fresh fuel . This time I replace the nearly new (12 hours use) spark plug- now it runs sweetly.

Moral of the story? There are no short cuts and if I had replaced the fuel and the plug originally I would have saved myself a load of inconvenience
 
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