Mariner 4 stroke EFI misfire help !

[James jameson]

Any one help with the following issue

I have a Mariner 4 stroke 60hp 4 cylinder EFI engine which previous time out ran fine no problems.

However this time started as usual, ticks over but when applying any revs it misfires and won’t rev.
as it misfires the engine icon appears on the display and it beeps
I have no diagnostic code reader so that’s out !

I have so far …..

Connected fuel straight to the engine bypassing the remote fuel filter
Cleaned the on engine low pressure fuel filter - wasn’t dirty
Ran from a separate fuel tank with fresh petrol (other petrol was only a few weeks old and the dear stuff !)
Stopped engine between each removal plug lead one at a time and restarted same no obvious cylinder. Not easy to get at with the engine running

I haven’t yet removed the plugs and cleaned them but would have expected the last step of leads to show something related.

any further ideas or experiences that may point me down the route to a solution ?

 

[QBhoy]

Any one help with the following issue

I have a Mariner 4 stroke 60hp 4 cylinder EFI engine which previous time out ran fine no problems.

However this time started as usual, ticks over but when applying any revs it misfires and won’t rev.
as it misfires the engine icon appears on the display and it beeps
I have no diagnostic code reader so that’s out !

I have so far …..

Connected fuel straight to the engine bypassing the remote fuel filter
Cleaned the on engine low pressure fuel filter - wasn’t dirty
Ran from a separate fuel tank with fresh petrol (other petrol was only a few weeks old and the dear stuff !)
Stopped engine between each removal plug lead one at a time and restarted same no obvious cylinder. Not easy to get at with the engine running

I haven’t yet removed the plugs and cleaned them but would have expected the last step of leads to show something related.

any further ideas or experiences that may point me down the route to a solution ?

Not sure what age this is…but I’m sure there is a small fine fuel filter in the fuel rail on some of these. My 115 has one. Other than that, it may be in limp mode as a result of low oil or a few other things that can cause this.
Sorry to ask, but is it doing this when in gear and underway? Just that these modern engines won’t let you rev past about 2500 rpm if you are revving in neutral. Thought I’d ask anyway.

 

[James jameson]

Not sure what age this is…but I’m sure there is a small fine fuel filter in the fuel rail on some of these. My 115 has one. Other than that, it may be in limp mode as a result of low oil or a few other things that can cause this.
Sorry to ask, but is it doing this when in gear and underway? Just that these modern engines won’t let you rev past about 2500 rpm if you are revving in neutral. Thought I’d ask anyway.

Thanks for your reply.
i will look for another filter,
oil level is and has been ok I regularly check this
it’s same in neutral and in gear. It’s noticeably misfiring not just revs held back

Engine age is approx 2016 I believe

 

[Mr Googler]

Duff coil?

unplug the coils one by one. The one that doesn’t effect it is the culprit

 

[James jameson]

Duff coil?

unplug the coils one by one. The one that doesn’t effect it is the culprit

I have tried that whist it miss fires and no noticeable difference
i would expect a drop as you suggest

 

[Portofino]

Has it got a cam position sensor ? If so needs It to run smoothy at higher rpms .

 

[James jameson]

Has it got a cam position sensor ? If so needs It to run smoothy at higher rpms .

It has I have seen that in the manual and have since found a resistance measurement to test for.
thats my next investigation once back to the boat

 

[James jameson]

By way of an update.
Drained the vapour separator on the high pressure fuel pump
Ran wynns injector cleaner through the engine and now is running sweet

I did find the magnets under the flywheel had come unstuck so have re bonded them back on

 

[westernman]

Any one help with the following issue

I have a Mariner 4 stroke 60hp 4 cylinder EFI engine which previous time out ran fine no problems.

However this time started as usual, ticks over but when applying any revs it misfires and won’t rev.
as it misfires the engine icon appears on the display and it beeps
I have no diagnostic code reader so that’s out !

I have so far …..

Connected fuel straight to the engine bypassing the remote fuel filter
Cleaned the on engine low pressure fuel filter - wasn’t dirty
Ran from a separate fuel tank with fresh petrol (other petrol was only a few weeks old and the dear stuff !)
Stopped engine between each removal plug lead one at a time and restarted same no obvious cylinder. Not easy to get at with the engine running

I haven’t yet removed the plugs and cleaned them but would have expected the last step of leads to show something related.

any further ideas or experiences that may point me down the route to a solution ?

May be old fuel? Or 95 when it wants 98 octane??