Saving Old Seagulls

Hi just put a new set of rings on my 40 plus
had 70 psi so thought it was about time i did it, she has now got 120 psi.
This is the first engine i bought and is not original its got a British racing green long range tank and a very light green crank case and magneto,
i really did not want to spoil the paint so was very carefull
all the nuts are painted so putting spanners on them has spoiled the paint, i put 4 new head bolts on but reused the 2 crank bolts
it came apart very easy
the water flow has never been brilliant but it did flow so i was surprised at just how much crud was in the water passages, the top half was clear
but the bottom around the water inlet was solid with a tiny hole that water got through and a sort of rusty sandy sludge for an inch up
any way, put it all back together and the next evening give it a run in the barrel and it worked a treat great water flow and more power so time for a day out.
We decided on south stoke on the Thames its a very long stretch between locks , it runs from streatley down stream through South stoke Cholsey moulsford
wallingford and up to benson lock.
Needed some 2 stroke so popped into Sheridan marine, (the home of British seagull today) and then the thought occurred to me forum members would probably
like to see it to,
so heres a link to youtube https://youtu.be/s1jHoSkcQYk

Hi,

The real benefit, if you ask me, is that you removed the crud! 70psi is a bit low for forties but would still run for a looong time.
Certainly 120 is better but does it sounds too high? Correct me if I am wrong, I thought that forties at their best reach 100psi.
(Honing also raises compression)


Anyhow now you have a great engine. Happy boating!

Now you've had the engine apart,you can appreciate why we make such a point of making sure the waterways are clear!
On the plus side your motor should last for another 20-30 years before it needs another overhaul.

I've always found the 40's to run quite well when the compression is between 70-100 psi (which seems to be the norm for most of them, but not counting the "little model 40's" as they are slightly different)
The LS that i've just rebuilt has 105 psi which i consider to be pretty good for one of these.
Give your motor a nice long run on the boat and re-check the compression again. It might drop a little once it's had some time to bed itself in again which is quite normal.

Well done on preserving another seagull and long may it continue


jon

Hi lads,
sorry for the late reply,
Yes you are dead right about the water passages,
its was a surprise how much water was working its way through such a small gap,
Jon, i checked the compression after running for six hours and it is down to 112 psi,
she always had a small leak on the tiller side of the crank case but now it bubbles on full throttle
but i never run on full throttle anyway, ( you do have to try just to see, once run in )
i wont do any more to her though because the paint will get spoilt,
this engine is the first i bought it started me on my love of Seagulls and all the the ones that have followed since.
Hi Stelios honing definately works i have just rebuilt an sjm and kept the old rings it is showing 99 psi,
it also has a small leak on the crank case by the tiller, (after 60 years i think most of us leak a bit by the tiller )
I allways think Sheridan marine looks right for the home of british seagull when viewed from the river, it looks like its straight from the 1950,s
apart from the modern boats outside,

Heres a picture of the sjm on first run after being rebuilt

Looking good now. Well done, good to see another one saved.

Keep your eyes peeled a bit later on (possibly on a later post) but there will be some "new pics" of Sheridan Marine making their way on here quite soon.

jon



ps if it were me, i'd still have a butchers at that leak, you never can tell with some of these "oldies" but that's just me