Well I'm a happy man after " one final look at the engine" last weekend
After leaving the engine for the Winter & doing nothing more this year, I agreed with the wife that I'd sell the engine on ebay as soon as we got back from a week away in Devon (nice break - did some sibbing & fishing).
I took it out, put it on the stand & took pictures ready to post it on ebay & then decided to try one last time to see if I could get the engine running again. Well it started OK after a bit but as before, it ran on full revs so I shut it down.
This time I had a look around the carb after a quick read of the manual (a refresher from last years attempts). I remembered that the primer float was stuck so I took it off & disassembled it - finally it was freed up & working OK & put back together again. i tried the engine & it started straight away but was still revving too high.
Why I hadn't noticed it before (or had it register in the brain) but I was thinking of what a carb does & how it works & then Ahha!!!! ...the butterfly was stuck, of course!! this might be it. I freed it off & got it got it springing back correctly & announced that "I might just have cracked it this time !!
I tried it again & sure enough, I had!! ...it ticked over beautifully & revved on command this time. Needless to say, we were very pleased & now, after a bit of tinkering & adjustment + a change of gear oil, it's running great, shifts into forward & revers well & it's ready for the water. So now my original hope of having a good running engine is realised.
Many thanks once again for all those who gave their valuable advise to me last year...my wife now wants to use the Mariner as soon as possible on the sea...Me too!!