coughing and spluttering optimax

Miller · 28 July 2011, 17:54

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 · 28 July 2011, 20:00

You could ask Martini

martini · 28 July 2011, 20:23

Quote:

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 · 28 July 2011, 21:04

could be worth checking the seals on the new filters

Miller · 28 July 2011, 21:27

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 · 28 July 2011, 21:57

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 · 29 July 2011, 00:42

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 · 29 July 2011, 07:58

Quote:

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 · 29 July 2011, 12:02

Quote:

Originally Posted by Jizm

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

‪135 optimax bad low pressure fuel pump‬‏ - YouTube

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 · 29 July 2011, 14:15

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

Miller · 30 July 2011, 00:12

well, managed to get someone to service it on short notice..no doubt the laptop will tell em i ve got a lemon!!

Weds will tell, misiing some prime diving weather!aaargh!

Turbodiesel · 31 July 2011, 19:34

You should have given us a call, 10% off for Ribnet members and we are just up the road from you!

Miller · 01 August 2011, 20:43

Quote:

Originally Posted by Turbodiesel

You should have given us a call, 10% off for Ribnet members and we are just up the road from you!

no worries, i ll give you a call next year for a service then...do you come up as far as Plymouth?

Turbodiesel · 04 August 2011, 19:46

Always in Plymouth. First job tomorrow is Plymouth, 2nd job is Penzance!

Turbodiesel · 04 August 2011, 19:47

Did you get the problem fixed out of interest?

Jizm · 04 August 2011, 21:11

Wondered the same????

Miller · 07 August 2011, 00:45

well, they have given the engine a clean bill of health, changed a diaphram on the LP fuel pump just to be on the safe side.

He told me to change the primer bulb as wasnt too sure of that one... Computer said all ok so I shall take it out 2moro and see.

If not I have the phone at the ready for monday!

Turbodiesel · 07 August 2011, 20:20

Quote:

Originally Posted by Miller

well, they have given the engine a clean bill of health, changed a diaphram on the LP fuel pump just to be on the safe side.

He told me to change the primer bulb as wasnt too sure of that one... Computer said all ok so I shall take it out 2moro and see.

If not I have the phone at the ready for monday!

No worries!!

Miller · 08 August 2011, 20:17

well, touch wood everything is working fine....still get a problem with the primer bulb not pumping fuel from the separator even though I have fitted a new one but the engine is not getting starved of fuel.

I have a fuel switchover valve so I can switch between the main and reserve tank and i m sure this isnt working properly...Can valves/seals go on these things?

Turbodiesel · 08 August 2011, 20:56

It really depends what type of change over switches you are using. Most of them are just a ball valve which dont usually wear.