cutting out

[erle bartlett]

Greetings all, I'm a newcomer to Seagulls but had a lot of experience with air cooled 2 strokes, mostly mowers. I found the forum guide most helpful in setting up the motor I bought recently and have it going nicely, except for one thing..... runs for 15 or 20 mins and then loses power and stops. Starts again straight away (with choke, 2 pulls) and runs nicely for another 15 or 20. Any suggestions? It's a bit uncomfortable when a fresh NEasterly is blowing across the Basin.

[Adrian Dale]

I cut and past from the SOS FAQ

"Sadly this is classic sign of the leaking head gasket, so the head is going to have to come off. I know, it says 'Do not Remove' Yes, it is for a reason, you do not have to de-coke, as we once did with two-strokes, and these screws actually go into the water-jacket, so they can be more than stubborn to remove. A gas blow lamp helps, plus some WD40. They are 5/16 BSF if you need to clean up the threads later..... I now have new S/S head bolts! £2.50 each, same price as rusty ones!

When you have the head off, check there are no faint black marks in the bore... This could be the only sign you might get that the block has cracked, giving the same symptoms. Normally the outside of the block will have gone as well, time to find a new block.... Yes I do have them, for the Forty and the silver Century, but at a price!

Assuming the block is OK, refit with a new head gasket, they are cheap enough, with heat proof silicone sealant, sold in car accessory shops as 'Instant Gasket' or 'No Gasket', orange or black in colour. British Seagull recommended it, as the head and block joints are often not smooth. Tighten bolts finger tight only, leave for 4 hours before finally tightening to 18ft lb, a good hand spanner tightness!" Courtesy of John of SOS

AJ

[erle bartlett]

Okay, I thought I'd seen that somewhere! I kept searching this help forum for it.
I read the advice with some trepidation regarding removing the head bolts, then I tried it, just to see. All the bolts turned! 18 ft/lb? Maybe just. What is the correct size spanner/socket for these? 17/32"?
They don't look too rusty either, just the odd spot of rust on the bolt heads. I wonder if someone has been here before me?

[Hugz]

1/4 Whitworth. Which country is your St Georges Basin in? We have one in NSW Oz.

[supersaint61]

if possible i always run the engine for a minute or 2 before removing the head just to warm it all up.. and head bolts are just as likely to break putting them back in as taking out as we all think "just a little bit tighter"until 1 snaps .. i always use new stainless bolts when refitting a head ..

[Horsley-Anarak]

What is the correct size spanner/socket for these?

5/16" B.S.F.

13.34mm across flats, 0.525" across flats or 1/4 W, 5/16 BSF spanner or socket.

H-A

P.S. The most important thing is cleaning the threads in the block before replacing bolts. I have seen people using replacement stainless steel bolts without cleaning the threads.

The new bolts bottom out on the rusty crud and don't pull the head down tight.

[erle bartlett]

Which country is your St Georges Basin in? We have one in NSW Oz.

That's the one!

[Charles uk]

A2 Stainless bolts are not as strong as plated mild steel ones!

[erle bartlett]

if possible i always run the engine for a minute or 2 before removing the head just to warm it all up.. and head bolts are just as likely to break putting them back in as taking out as we all think "just a little bit tighter"until 1 snaps .. i always use new stainless bolts when refitting a head ..

Fortunately there's a tension wrench in the bottom of the toolbox. Finding the right socket might be harder to do.

[erle bartlett]

Thanks for all the tips, I think it is going to take me longer to put the tools and parts together than to do the actual job.

[Charles uk]

I belive John carries all the correct tools in the form of a toolkit!

[Hugz]

I believe John carries all the correct tools in the form of a toolkit!

Will still need tap and di. Does John have those? If not Coventry fasterners can help. There is a branch in Wollongong. Only a hundred k's away. You will be back by lunch though I always end up getting fish & chips at Kiama blow hole. Go for 5/16 BSF thread.

http://www.cgl.com.au/cgl-corporate/loc ... SouthWales

[erle bartlett]

I belive John carries all the correct tools in the form of a toolkit!

I've looked, but can't find it. Still finding the best way to navigate this site. Any chance of a link to the tool kit? If for no other reason than to see what's in it and what I will want apart from what I have.

[erle bartlett]

I believe John carries all the correct tools in the form of a toolkit!

Will still need tap and di. Does John have those? If not Coventry fasterners can help. There is a branch in Wollongong. Only a hundred k's away. You will be back by lunch though I always end up getting fish & chips at Kiama blow hole. Go for 5/16 BSF thread.

http://www.cgl.com.au/cgl-corporate/loc ... SouthWales

F&C at the Blowhole is always a good break to the journey, but I'll see what I can scrounge up first from my engineering mates.

[Hugz]

F&C at the Blowhole is always a good break to the journey, but I'll see what I can scrounge up first from my engineering mates.

The best mates to have! Any of them good on a lathe?