coughing and spluttering optimax

[Miller]

I have just tried to take my boat out today for a run; waiting for a service though did about 10 since my last one!

Anyway, changed the fuel filter on the engine myself and retightened hand tight and have fitted a new water separator as paranoid about water in fuel!

Anyway, started fine, ticked over fine and was ok around 5/10kts.

When we took it out and opened it up, it goes fine for a short while then coughs, spluts and misses like its starved of fuel..when you back off the throttle and throttle back up it goes fine then cough splutter. The separator is full and there is fuel in the bulb but I m reluctant to take it too far as I dont fancy rowing!

Any ideas?

Thanks

[Pikey Dave]

You could ask Martini

[martini]

Originally Posted by Pikey Dave

You could ask Martini

I know of some great Mercury techs in Paris, do you want their number?

As you say it does sound like a restriction in the fuel delivery but I can't see a reason why changing filters would cause it. Have you definitely used the right parts? Kinked a hose somewhere whilst doing the work? Can you hear the fuel pumps kick in when you turn the ignition on? And they run for around 3 secs then go off?

[Ian Sharlot]

could be worth checking the seals on the new filters

[Miller]

I have checked the filter and there is no leak there...The pump runs when you turn the ignition on as well.

How about spark plugs? They were changed last year when it was serviced and its probably done 20 hrs since then at most...Is that a possibility?

[Chris]

I would run a jerry can to the engine bypassing all the filters. If it runs then you will need to work your way back from there to identify the restriction or leak.

[HUMBER P4VWL]

Sounds stupid, but check the loom as it enters the engine. Ours after only 2 years had worn through where it enters the engine and turns/twists/creases. Basically when we opened up the throttle, then trimmed out, it creased and shorted a wire where it was worn.

Worth checking.

[Jizm]

Originally Posted by Miller

The pump runs when you turn the ignition on as well.

Remember there are 2 electric pumps, high and low pressure.
Is this anything like your symptoms?

‪135 optimax bad low pressure fuel pump‬‏ - YouTube

[Miller]

Originally Posted by Jizm

Remember there are 2 electric pumps, high and low pressure.
Is this anything like your symptoms?

hmm, not quite it goes for a lot longer at full throttle before it starts to struggle...

First thing i ll try is the external tank as it took me ages to get the ball primed in the first place.

[Jizm]

Indeed, they don't much like sucking up air....