80hp Mercury Blueband new plugs now wont start

[Mark Of Loxley]

I have an early 80's Blueband Mercury 80hp. It was running fine bank holiday weekend. But thought it was due for some new spark plugs.
Got them fitted today and it just wont start up.
Turns over.
and over
and over.

Not even a hint of catching.

Any clues as to where to look please ?
Cheers
Mark

PS
I did label the HT leads before removing so they are fitted in the correct order.

[secondopsman]

First thing i would do is put the old ones back in and try again.
Wouldnt be the first time that new plugs are duffers.
Didnt get them from Minofern did you?
Pete

[Mark Of Loxley]

No, got a motorfactor in Gaerwen to order them in for me as I keep the boat on Anglesey. I did wonder about putting the old ones back in, but then it started to rain again so thought i would leave it until the morning. I do have another 3 new plugs that i bought from another dealer ( the green spark plug company ) that I haven't tried yet.

If the old ones dont bring it back to life then what ?
At £7 a plug it would be a bit annoying throwing them out if they are prone to being duff as you say.

[willk]

You've checked the killswitch, I presume?

[Mark Of Loxley]

Hi, Yes I did check and re-check the kill switch.
Managed to resolve it in the end with some advice from a fellow boat owner at the boat yard.
First off, the suggestion was I could have totally flooded the engine.
I had established i was getting a spark by trying the plugs against the engine block.
So removed all spark plugs and just turned the engine over a few times again and then left the plugs out for 10 minutes to let the excess fuel evaporate.

I replaced the plugs and tried again, nothing, just kept turning over and not attempting to fire up.

Was just giving up and putting the cowling cover back on when I noticed the manual choke knob on the casing; I had previously only used the key push operated choke; so I pulled that out, pushed it in, pulled it out again.
Turned the key and there has a hint of an attempt to fire up.
Turned the key again and it was biting but not firing.
Third turn of the key and it bubbled into life !
Bingo, water pumping, engine idling happily.
Left it for a few minutes idling.
Key off, key on, instant fire up and ticking over nicely.

All sweet and happiness again !
Lesson learned on flooding engine and how to deal with it.