Mercury 150 four-stroke intermittent fault

[ISLANDRIBBER]

Hi All,

I've got a 150 Mercury (2012) which over the last couple of months has developed an intermittent missfire. Problem has been getting worse until last time out it misfired most of the back to the marina (about 1h). No engine warning note just a persistent misfire. Got a diagnostic computer on it but showed no problems and then ran it with the muffs on for an hour or so with no problems. Water separator looks clear so doubt it's fuel Anyone come across something similar where a diagnostic check doesn't pick things like this up?

All help gratefully received.

[AMac]

Faulty coil pack breaking down when heating up

[Lee argyle]

+1 coil pack, with the engine running unplug each coil in turn - one won't make any difference to the 'miss'

[ISLANDRIBBER]

Thanks Guys,

I'll check it out.

A

[jambo]

Is that OB one of the new style150's?


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[Xk59D]

yes it is a new style one if it is the boat i think it is, we met at largs on way out...nice boat!

clyde outboards have fitted a few of those so maybe worth a phone call if all else fails.

[jambo]

Originally Posted by Xk59D

yes it is a new style one if it is the boat i think it is, we met at largs on way out...nice boat!

clyde outboards have fitted a few of those so maybe worth a phone call if all else fails.

Thanks Paul. I'll give Cammy a phone.


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[ISLANDRIBBER]

Yeah, Boat lives up near Oban in the Summer. Sound of Jura gets awful big when the OB starts misbehaving.

[HUMBER P4VWL]

We had intermittent Mis-fires on an opti for a few months once. It had occurred at random trim and/or steering and/or power positions so property confused us. Plus no warning signals.

Couldn't figure it out at all, changed lots of things including plugs and HT leads etc until we noticed a wire worn through on the main thread as it entered the cowling.

Check your wiring basically.