Saving Old Seagulls

I have to share this - after buying a 40plus (Mk1 Ignition and clutch )(amongst other Seagulls and stuff) which had not been started or run for 3-4 years - but had been refurbished prior to that - gapped the plug,checked the floatbowl, gearbox oil and put a litre of fresh mix in it. Pulled the starter - fired first pull without hesitation - ran for a few minutes in a drum of fresh water and shut the motor down. Restarted it - first pull again and pumped water like a new one. I thought that was pretty darned good! Repeated the same excercise next day - same results.
Question: The owners manual (itself one of the best reads you will have - partic the 19th and similar editions) states that a motor should not be run in a tub of water for more than a couple of minutes - even if the motor has a clutch or you have removed the prop with the clutchless models.
Why is that?
If you don't over rev the motor and it is pumping water fine - apart from the risk of asphixiation from that choice 10:1 mix what damage to the motor can this cause?
P.S.The advice on the FAQ re petrol tap cork repair is priceless - works a treat.

the more seagulls in queensland the better, the smoke helps keep the mosquito population under control,

chris wrote:the more seagulls in queensland the better, the smoke helps keep the mosquito population under control,

Chris, it is a wonder you didn't notice the blue haze drifting over the hills to Clontarf - makes an old Victa look like an amateur..

nothing like the smell of 2stroke in the morning

Baby Sis lives in Gympie and she mentioned a sudden cloud the other day

Not really sure about the advice in the manual, only thing I can think of is motors prefer to run under load, if you have de clutched or de propped then you are obviously running without any load. Am sure a real expert will correct if I am wrong but I think running without load means small throttle openings for relatively higher revs so a bit less lubrication, thats how I always understood it, and as you say there is the added risk of overrevving. If you fit / engage the prop you have more load ( still not the same as running on the boat though due to froth etc ) so its better but then you have the cooling problems.