Free Up a Seized Piston: British Seagull Outboard engine + Impeller, Gearbox Oil Seal & Carburetter
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- เผยแพร่เมื่อ 24 ก.ย. 2013
- Fully seized 2 stroke Seagull Outboard Engine Restored and Running. Gearbox removal and seal replacement, Water pump / impeller change and carburettor repaired. The principles are the same for most seized piston engines, be it a lawnmower, motorcycle, car or outboard motor as shown here.
Hope you find this video useful. Please remember to share and like it, this really does help more people to find my videos. I look forward to reading your comments. Kind regards Andrew - แนวปฏิบัติและการใช้ชีวิต
If you have a really badly neglected motor it will need a serious amount of effort to shift the piston. It seems that people drop them over the side, fish them out then leave them in their garden or a shed for about five or ten years. Next when they find how seized it is they put it on eBay!
Motors that have a crankshaft seizure as well as a piston seizure need to be peeled like an onion and a Seagull 40 FP877NI which was purchased in Plymouth was no exception. It was so bad that job number 1 was removing the lower unit (gear-case) With badly stuck bolts one can use a full size propane burner (40 kilowatts) but be careful as you do not want to melt the water pump impeller! Aluminium alloys expand at about three times the rate of steel so a little heat can reduce the vice-like grip caused by corrosion products. Once the gear-case was removed it was possible to remove the down-tube by heating and wiggling it after the screw was removed. The next job was the square drive-shaft that was rusted to the crankshaft. The propane torch was used again but the shaft had to be heated to a dull red before it would let go of the crank!
Once the power head is released from its ancillaries more peeling can be done. The head had already been removed by the previous owner so that was one less job to do. The flywheel was left alone for the time being as if one has a motor that has a crankshaft seizure, hammering can bend the crank! The crank-case bolts were removed and the lower crank-case half was removed (lots of Plus-Gas releasing fluid and time needs to be used) Once the big-end screws were exposed they were undone, however this is a tricky job that needs the correct size of screwdriver and Mole Grips (Vise Grip Pliers US) Releasing fluid can now be squirted onto the upper crankshaft bearing and once this is freed-off it is time to remove the flywheel.
The block and piston can be tricky but soaking with releasing fluid for a few days does help. NEVER strike the conrod as damage is sure to occur. The piston crown is not flat so hitting it there is also a bad idea. The solution that I have used with great success is to obtain an off-cut of thick wall scaffold pipe about four inches long. In the UK this pipe is two inches in diameter externally and about 1.5" bore. Some lathe work is required to turn some off the pipe down to 1.765 inches or 44.8 mm. It has to be a clearance fit in the bore. The pipe is actually a Piston Ejector and the piston can now be driven upwards. Even pistons that are severely stuck can be defeated. Of course the same idea is not so good on the 102 that has a fixed cylinder head.
Beware of storing the loose parts in cardboard boxes or in old ice-cream containers as parts may get lost. Discarded saucepans are more durable and their bottoms don't fall out.
Good luck!
I have searched youtube for this video! lol! I remember watching this years ago and now I have just bought a seized up Silver Century plus (I didnt know it was seized when i picked it up, but i didnt care because it was only £50 November 21!) but now that i have seen this video i will have a go at unseizing it. Good video. Thanks!
brilliant info on the gem of the sea bro
brilliant video , no bullshit , very refreshing having just bought two seized seagulls your video is invaluable . thank you very much
Fantastic simple video that delivers all the information that is required in order to service and repair this item. A great video made my a proper engineer - i think we share the same beliefs 'Keep it simple stupid' - Many thanks....
Thank you for that video!
Seagulls are really the best outboard engines for the world, they didn`t lie. If it doesn`t work, you`ll only need a hammer to get it back to work...
Or if there comes no water, you check the gearbox at first if it`s detached. If it`s nearly lost, the water stops coming out. But the engine works... My advise for that two screws is using locking varnish.
Thanks for that advice, will use thread lock in summer.
Good video Andrew
And that's coming from a true master!
Good old fashioned explanation Andrew. No blaring music of dubious origin, no flashing lights, no smart arsed commentator showing off. I looked at Phil Downes videos after he flamed you, now there IS a prat!. It was the bore that was seized and I don't think Seagulls had chrome bores on such early engines. Beacus e it's the bore that's seized, it doesn't put much stress on the con rod or crank and you only moved it a little to free it.
Alan Reynolds Thanks Alan, you are right they are not chrome and it was the bore that was seized. I suspect a seized crank soaked in diesel would shift using same method.
Thanks for sharing your great job. I'm the proud owner of a 59' made, and still working, Seagull LLS century. Esteve, Barcelona, Catalonia
Really enjoyed this Andrew, great outboards so easy to work on and reliable
That was a great video. I own 5 British Seagulls including one that is seized so it has me thinking. I don't know what was more impressive; your work on the motor itself or your ability to work in tight quarters!! Looks like you have worked quite a bit on these motors over the years. Thanks for posting this video.
Thanks for your comment. I have lots of experience with many different types of engines, including stripping down, fault finding and completely rebuilding a merc 135 hp without a workshop manual, which to my delight fired up first turn of the key :) Your seized Seagull is certainly worth reviving. We need to keep these amazing little motors running to remind manufacturers to build reliability into new products, instead of deliberately building known faults into products for short term profits on repeat business.
I fully agree and the seagull is the perfect example of simplicity and an outboard almost anybody can work on. All things that are complex and not useful; all that is useful is simple. Marketing and advertising today deceives people into thinking they need features and gadgetry that are next to useless and really of no benefit to the owner. You can really see this today in many of the 4 stroke outboards and oil injected 2 strokes. Do you ever work on Acadian or Atlantic make and break motors? These were used extensively here in Newfoundland by fisherman. They were also very simple and never even had a spark plug but some sort of heating coil- very simple.
If you have one with a badly rusted bore the method shown in the video will probably not work. With really bad Seagulls its a case of separating the crankcase halves and unscrewing the big end. Do not hammer the con-rod! Instead machine some steel pipe so that it is a clearance fit in the bore and longer than the con-rod. The pipe allows great force to be applied to the the bottom of the piston and done this way the piston skirt won't get left behind. Tremendous force will still be needed e.g. large G cramp,that can be hammered when it is as tight as possible. Plus Gas and heat also help. One may find that after all this and an overnight soak the note of the hammer will change to a thud instead of a ricochet. This means that the piston has moved! Good luck!
Andrew....super vid....and super T-Shirt...lol......cheers for the big colony!
Thanks J :)
Simplicity and very valuable and practical,Thanks for sharing
Nicely done, thank you !
Hi Andrew, thanks for a great video, really enjoyed it.😄
Very interesting video, I have a Seagull in my garage which hasn't been started in approx. 32 years. I will be trying to get it started in few days time. I will let you know how I get on!
great job you have done there
Your welcome :) Glad to be of some use. Good to here your seagull is serving you well after all these years :) We don't make them like that anymore. Thanks for your comment
very well explaned, if these engines are seized through being standing as is the case here the piston rings stick to the bore, but if seized because of overheating or lubrication deficiency le lack of enough 2 stroke oil then the piston will need to be replaced and barrel may need a rebore because of heavy scoring of both parts. a compressor would have been handy here in your video, good advice for people though.
Nah, from my days of riding a Maicoletta in the 1960s I can tell you that a lot of two stroke engines are not properly run-in until they have seized three times! One would become expert at relieving the black seizure marks (silicon oxide?) on the piston as the black marks were exceedingly hard and they would never bed-in.
A Seagull piston never gets as hot as the piston on a Maico unless the cylinder block is clogged with rust (yes I have seen that) and the muck, possibly Magnetite, was so hard that even masonry drills were struggling. With one like that it is time to get out the Dremel and some diamond burrs. Unfortunately the burrs are never long enough, not even for a 40+ but well begun is half done! A cordless drill with a torque-limiter set as low as it will go is the only suitable power tool that I own once the burrs have reached their limit.
The good news is that a Seagull can always be repaired which is more than can be said for some brands that come from the Far East. Often the alloy on the foreign motors becomes porous and crumbly. The other trick that they do is to use low-tensile bolts which are impossible to remove as the heads shear-off. Been there done that and discovered that replacement castings would cost far more than the motor was worth.
Just bought a seagull outboard on ebay lol! IM sure you vid will come in handy! And for the phill downes remark! Your a compleate fool! old school son! Old school!
Way to go Jason, these are amazing little engines from a forgotten age where reliability mattered.
Thank's Andrew! Got it home yesterday gave it a clean up! ONly problem is! No cable to start it! What do o order or ask for can you help? Jason.......
I was thinking a peice on cord with a nott?
Hi Jason, I used a cord with a knot in it. Make sure cord is thin enough so as not to get wedged in the flywheel pulley. Also make sure not too long so you pull it off the pulley each time when starting. Don't wrap the cord around your hand when pulling.
Many thank's.........
Très intéressant
bon mécanicien et le moteur tourne bien et fait un bon bruit.
Good luck
thanks 4 the help good video
Your welcome Roy, thanks for your comment.
super...
Been advised by John at Saving old seagulls to drop the impeller in a mug of hot water prior to fitting which makes sense. This will expand the impeller and allow it to slip down the shaft with ease,
Would you believe that Seagulls are some of the cheapest outboards available in the used market here in New Zealand? Admittedly they've all been sitting unused for some years, but I'm determined I'll find at least one that I can get working.
No Seagulls were hurt in the making of this video.
+Andrew K Fletcher
I love your video. I have some of these motors. I love to see how you fix the motor. Very easy to understand.
Thanks. Are you in UK?
Yes live in the UK, thanks for the thumbs up :)
Great video, I also need to replace my impeller & seals. Where do you get your parts from?
Chuck Taylor saving-old-seagulls.co.uk/
Does the seal between the bottom and the top half have to be tight? There is no water flo on my seagull when running. I re used the old seal and it doesn't seem like its tight enough. Will that effect water flo? Thank
mike97525 Hi, the seal / gasket between the top half and bottom half of the gearbox, if this is what you meant, would not account for loss of water flow. I would suspect the cooling galleries behind the cylinder head are clogged up with carbon, oil and mud as shown in the video. Presumably you have checked / replaced the impeller?
the impeller looks old but ok I will try the air compressor but if that fails I will take the head off and try not to break any bolts
thanks for your help
Hi, i have one of these outboards but the top bit doesnt spin i cant get it to move, does this mean its seized. If its not any advice on what i can do. Thanks
Yes sounds like it is seized and this should sort it. Has it been stored in a dry place?
I would first try spraying plus gas or squirting some diesel down the spark plug hole and leave stand for a day or more and then try placing a spanner on the nut above the flywheel and tapping it with a small hammer back and forth to see if it frees up.
Yes we have stored it in a dry place. Funnily enough, we are in the process of doing that exact thing. We asked my dad and he said to do that as this happened to him on our old outboard. We took the engine out of the shed as were are going to use it on our boat that we are building. Thanks for the help.
classs done that a few times on bikes like fs1e's
I have been trying to do this on my century 100 which has a ceased piston for a few days now, I have even removed the entire lower half from the power head. I have tried soaking it in penetrating oil overnight by poring some through the carb hole, where the head used to be and the exhaust. I have tried hitting it with a large hammer via a piece of wood many times and I have also tried heating it. I think If I can remove the block with the piston stuck in it from the kam gear thing at the top (under the flywheel) I can put it in a large vice and push the piston that way however I can not seem to disconnect the piston without it being out of the block. Any suggestions?
One suggestion made in the comments was to snap off the ceramic part of the spark plug, drill and tap it to take a grease nipple and use a grease gun to force the piston down. One problem with this is that if the piston is stuck with the inlet open or the exhaust open, it won't work www.2strokeengine.net/2strokeenginepics/exhaust.gif
Andrew K Fletcher the piston is right at the top so this may work however the crank and piston are therefore straight so pushing may not do it and I may need to rotate the shaft at the same time. Thanks for the help
Andrew K Fletcher I finally freed it by removing the cylinder with the piston in it by disconnecting the Conrod from the shaft and removing some studs. I then made a rig for a vice that put force on the piston and i very slowly started to move it out by using the mechanical advantage of a vice. I also profiled a piece of wood to fit the piston head to spread the load. The piston is toast but the bore is really good so I'm going to re hone it and get a new piston.
Great job. Another Seagull will soon be flying :)
Andrew K Fletcher
Indeed it will, also I told some people in my boat club about it and I now have another seagull that is ceased to repair!
never bang on water impeller with hammer
Y'know, it would be such a simple and intelligent thing to do to put a shield between flame and plastic carb bowl...???
However, I've reached the conclusion after watching dozens of videos and a few emails and phone calls all over the world intelligence and British Seagull is an oxymoron.