40+ loosing power

[david doyle]

Water flow is no indication of proper cooling. My experience is limited to 3 blocks which all pumped alot of water but all 3 had almost 50% of the waterjacket completely blocked by rock hard crud. The remainder of the interior water jacket area (where water was flowing) had an insulating layer of of rust almost as thick as the cylinder walls! The water flowing out of these engines was 'cool' to the touch most likely because it was not able to pick up any heat. Now that you have the bolts out definetley get the head off.

[Horsley-Anarak]

It sounds like your cylinder may be over heating, You will need to remove the head and clean out the water passages.

If you get the head off, it will look like this I would think.

There is water flow but a large part of the water passages are full of rust.

This lets the engine over heat and you will get a partial seize.

If the bolts shear, they normally do it at the level of the head, this leaves a stub of bolt that usually comes out if you apply heat and tap it with a hammer.

I find that Mole Grips are the best tool, work it backwards and forwards then the remains of the bolt will come out.

As has been said before, if you want a reliable Seagull that may be 30 years old, you must remove the head and clean the water passages.

If the bolts shear off then replace them.

Also when it is bits, check the water pump condition.

H-A

[anne-marie]

thanks for the picture, i finally undo the head gasket; and , surprise, the waterway was full of rust, except one hole....so i scratch it out, blew in it, seal all the parts, cankrase and head with the orange sealant....but no compression...did i missed a thing?

[Stelios_Rjk]

RTV needs 24hours to cure. I never spin the flywheel before the sealant is fully cured because that could hurt the sealing. Apart from that there may be an error in assembling or the way you close the head. Could you describe the way you followed to close it?

[anne-marie]

well, in fact i undo cankrase 4 bolts, sealed cankrase joint, tightened the 4 bolts, then sealed cankrase to the full block (with head on), after sliding piston inside, tightened 2 bolts, then re tightened 4 bolts harder, then reput the sprk plug and tightening it i undo the head gasket (cos i undone the 4 bolts before) so i removed the copper joint, cured water way, blew in it, sealed the 2 faces of the block, tightened head bolts, and put back tank, spark plug, carb....what was wrong?

[anne-marie]

hi horsley!
how did you remove rust from waterway's holes?

[Stelios_Rjk]

Did you put back the copper gasket? This also requires a preparation, it's no that simple.
The rust can be removed with a hand held drill.

[Horsley-Anarak]

hi horsley!
how did you remove rust from waterway's holes?

I use a small electrical screwdriver and a hammer, just keep chipping away until the passages are clear.

H-A

[Stelios_Rjk]

When putting back the cylinder head...

Clean thoroughly cylinder face and cylinder head. I remove the remains of previous sealant with petrol, then clean with acetone then heat a little bit the surfaces with a blow torch. The blow torch removes most remains of any oily/greasy substances. Then slightly rub the surfaces with 1000 wet & dry (wet in this occasion) grit. Remove any remains with a clean piece of paper and then again with the torch to remove any moisture. Don't overdo it with the torch. A little heat will do the job.

The copper gasket. I leave it to soak in petrol. That will remove any previous sealant. It may need rubbing with grit to remove rust. You could start with 500 wet and dry grit and go gradually to 1000-1500 grit. The whole rubbing is done underwater and in case there are remains of rust on the copper gasket. Between these two stages petrol can be totally removed with the torch.

After having cleaned the gasket I hit it with a flat hammer where the signs of the water passages are to become flat again. Then I heat it with the torch until it gets glowing red. Then let it cool slowly. That makes it soft (annealing).

You can avoid the procedure with the gasket if you buy a new one, which is also recommended.
Be extra careful if you remove petrol/acetone/oily or greasy remains burning them with the torch, that could lead setting fire where you wouldn't like to. If you choose to do so, do it outdoor with all precautions.


This is what I do and seems that works. But I may be wrong, I would highly appreciate it if anyone point in any error that I may do and correct me.

[anne-marie]

thanks for your advice!
i'll do as you say your a wise man.
i think thats gonna be even greater than before with my old little boat!

[Stelios_Rjk]

I am rather beginner! Please wait for more experienced members to verify the procedures I follow.

[phil]

When you clean the water jacket pay particular attention to the area near the exhaust outlet. With the water jackets facing up to work at cleaning them out and the exhaust outlet facing toward you the left side of the bottom of the water jacket has an area that is quite difficult to reach and it should be cleaned out. It usually takes me 45 min. to 1 hour to do a good cleaning job on a well rusted up water jacket.

[phil]

I disagree with David on his statement about water flow not being an indicator of proper cooling. As long as there is good water flow the cooling IS adequate. The normal exit temperature for water from a Seagull is below body temperature. When running full bore and pushing a heavy load, a Century may have exit water slightly above body temperature. This for freshly cleaned out water jackets and as long as there is decent water flow the temperature will be similar. The only time I see hot water exit a Seagull is after a period of no water flow when idling. Long shaft motors may run slightly hotter but probably not noticeably.

Therefore if the water flow is adequate I don't think it is a good idea to clean out the water jacket. A motor that needs to be dependable for frequent running may be a different story, but even there if good flow is observed I haven't seen them stop circulating quickly enough to be a problem or a danger.

Reminds me of the Seagull owner complaining about the motor quitting but being able to start it after it cooled down,when someone asked how is the cooling water flow? His reply was, " Isn't it an aircooled motor"

[Oyster 49]

Not cleaning out the water jacket on an engine you don't know is the engineering equivalent of burying your head in the sand. The crud will build up, water flow will not reach the places it should, and hot spots will be created. Then the block will start to crack and bingo, your block is scrap, and the seagull ends up thrown in the corner of the shed.

Clean out the water passages if you want an engine to A. last longer and B. Be reliable. It's a sensible piece of light overhaul work, and I do this to every engine I see. It's essential routine maintenance.

My FPC was like that, water flow was good, but one side of the block ran cool, the other side got very hot, to the point of paint peeling off. Half the water jacket was completely blocked and was getting no cooling at all. A couple of hours cleaning out the jacket and all was good.

The other good thing about clear water passages is that cooling water will easily drain out when you shut down the engine.

[phil]

My point would be that you could feel the hot spots without taking the head off, and that removing the head and reinstalling it is beyond some Seagull owners skill level and equipment supply ( ie. drill press, assortment of drills, and BSF taps and dies) especially needed if they should happen to break something while removing it.

The dire results that you describe have never happened in my experience. Yes I clean them out if they need it, but then I have the experience, equipment, and tools to complete the job should that become necessary. So in my opinion, giving people the impression that the first thing they should do when they get a Seagull is immediately remove the head and clean the water jacket is not the best advice for everyone that comes to this forum for advice.

So if I get a new to me Seagull and it produces a pencil thick stream of water from the water jacket when running above idle with no hot spots on cylinder the head is staying on until there is an actual problem.
Again this is only my opinion.