Hmm-m-m-m-m. This was my suggestion and yet, many thoughts as to what to consider if looking at a possible Seagull purchase go back to stuff that's covered on the Before You Start your Seagull
or the Tools Required
sections. That being the case, I'll begin by adding a few notes that cover the purchase of any second-hand outboard engine while trying to tailor it toward the specifics of the British Seagull line.
When looking at any used engine it's a "pig in a poke", an unknown on so many fronts. Obviously, if the engine is advertised as a running unit, that helps to remove some of the mystery if you trust the seller at his word; the very best circumstance would include you being given the opportunity to see it running first. Let's begin, though, with an engine found in a barn or at a yard sale, being sold by someone who knows little or nothing about outboards or about antique engines specifically. Before you go looking, please read the section of this board that addresses "Before you start your Seagull for the first time", and "If after all the initial preparation..." so that you have a feel for what you might have to get into if you find problems that we'll address here. Some of this discussion will be redundant upon that advice and some may seem incomplete compared with those steps. Another thing that's worth doing, is to take note of the type or series of engine that you're considering and compare it with samples from this board's Seagull Gallery (http://www.saving-old-seagulls.co.uk/ga ... allery.htm
). See how the tank, transom clamp, carburettor, and other stuff looks and matches up with the engine. Does it look genuine, or is it a hack job with any manner of sloppy repairs having been done before? Poor workmanship displayed on the outside could indicate a similar lack of care on the inside. Don't let the mistique of buying a classic or an antique override your judgement as to it's overall condition.
Before you go to look at an engine someplace, take along some basic hand tools but chiefly a spark plug wrench and a large blade flat screwdriver. You might perhaps take along a ____mm socket & handle or better yet, a ____BSF spanner [for the head nut], a mallet, and a little outboard engine oil. Take a compression gauge if you own one, and a torch/flashlight.
A "barn find" may be perfectly operable though you'll want to do some basic dry tests to see if it's worth your time to fool with it, while a long-time neglected engine could be trouble; this assumes of course that you aren't a collector who would take any Seagull for the spares alone. To start with, can you turn the flywheel around without much resistance other than what seems like cylinder compression? If the flywheel doesn't turn at all, you could be looking at a piston frozen in the cylinder by corrosion that may or may not be recoverable. If you're very mechanically inclined, offer a little money and see what happens. If the flywheel turns but it's quite hard to do so, it may have some surface rust inside the cylinder that should be easy to deal with.
Will the owner allow you to remove the spark plug? If so, do that and see how that affects rotation. Look inside the cylinder to the extent possible and see how rusty the cylinder wall looks. Also, open the throttle up fully and shine some light down the throat of the carburettor. You'll see the piston at one stage of compression or another; rotate the flywheel and see if the rings have corrosion on them. All other factors being equal, you can assume the cylinder walls look similar to that.
Will the owner allow you to pour a few CC's of oil into the cylinder? You'd only be doing them a favor at that point... If so, does that aid in the flywheel rotation? If so, your journey toward repair and running won't be so terrible and you can skip ahead a bit. If adding some oil does little to aid a stiff rotating engine, there could be other problems to address that we'll get to, though the possibility of main bearing troubles should not be ignored. If it's still difficult to rotate the head after adding a little oil, will the owner allow you to pour some oil into the carburettor inlet? If so, pour a generous amount in there and stand the engine up on it's leg for a moment, then invert fully so that some oil reaches the bottom and top bearings. Try rotating the head a few revolutions; if that helps, you're probably going to be OK with this find. If not, then there are still a few other things to look at.
If allowed to do so, hook up your compression gauge. A few pulls should offer ____lbs/sq.in. on a Century series and ____lbs/sq.in on a 40 series. If you don't get that, add a few CC's of oil to the cylinder and repeat. Too little compression could mean the rings are frozen or could indicate a worn-out cylinder.
Let's assume that at some point in the preceeding, you've done what you can to establish a free-turning flywheel but you still don't have it turning as easily as might be expected (other than normal compression if the plug's in). If allowed to do so, remove the plastic plug on the gearbox and see if there's any lubrication in there. I say "lubrication" because the 140-weight oil that is used while in service, mixes with seawater and looks milky-brown much like heavily creamed coffee (but thick). If the gearbox is dry, that would add resistance to the flywheel rotation. If things are bad enough in there, it could possibly sieze the engine but that seems like an extreme. If that's dry but the metal parts you see don't look all corroded, and your flywheel still has a lot of resistance you're most likely still looking at cylinder rust from neglect over time. That's generally repairable.
Next, let's consider the electrical system. If you've been allowed to take out the spark plug and such, and if the flywheel rotates around easily enough that you can use the starting pull-cord in the traditional manner, hook the removed plug up to the high-tension wire and lay the plug up along the engine block. If you took a friend, have him/her hold it there. Give the cord a good pull and see if there's a spark at the plug. If there is, that's great. If not, see if there's an extra plug. If you brought the village idiot, have him hold the high tension line's end and touch the engine, while you pull the cord lightly. If he wiggles, you're probably OK with spark. If neither an extra plug or a suicide-test shows potential, you may have to do some cleaning of the breaker points which is easy. But you could also be looking at magneto problems. If this engine is strictly a barn-find that you're being given, use your socket set and remove the flywheel nut, and follow the advice elsewhere on this board that covers cleaning & gapping the ignition points, and then see if you get spark. If it's impractical or disallowed to start operating on the engine in this manner, then you're at the point that you'll have to decide how much work you want to get into, and make an offer in keeping with your own mechanical ability at small engines.
If you're happy at this point with the flywheel rotation and the ignition spark, but haven't checked out the gearbox yet, then this is a good time to do that. With the engine standing up as for operating, remove the plastic plug and see if there's heavy oil in there. See the aforementioned as to what to look for, but generally if there's oil or oil/water emulsion present and there are not rotational problems, you're probably OK in this department. If you rotated the head before and found it catching with mechanical resistance, with or without some intermittency, there could be a broken tooth on the gears. Take that into consideration if you decide to make an offer. If there is no oil in the gearbox at all, take a look inside (wth your torch/flashlight) and see if you see rust or broken parts. Hopefully, there will be at least some kind of lube in there even if the engine has been dormant for 30 years.
OK, we're this far and nothing's been said of the fuel system. My position is that if the bits up to this stage are messed up, the condition of the fuel system is superfluous. That's because, while fuel systems have their "personalities", they're repairable without tearing apart the engine. So here you are with this potential engine purchase and everything so far is working in your favor. Open up the fuel tank and see if there's anything in there. If there is, and if the engine has not run in a while, it's going to be terrible stuff. Count on a tank cleaning, which is not difficult for anyone to accomplish. If the fuel line is of the clear variety, is there dirt in it? If not of the clear part, the issue is moot until you get home. Look at the carburettor. If the owner will allow it, remove the float bowl (Bing, Villers) and see if there's a lot of crud in it. If that looks comparatively clean and if the general appearance of the carb insides is clean, as compared to corroded and eaten away, then there's little that could be wrong that you can't service at home. Try the throttle lever. Does it operate smoothly, or is it frozen? If so, you need to consider that this could be due to a stuck cable or it could be due to the throttle piston in the carb being stuck. If the owner will allow, remove the cable-to-carb cover (Villers, Bing) and see if that assembly comes out easily. If it does, then the cable is the problem but that's repariable. If the piston sticks, see if it's due to corrosion. If it sticks due mostly due to built-up fuel varnish, that's something you can deal with at home; corrosion in this area could suggest a similar condition within the carb passagways and you need to consider that a heavier stage of repair is indicated; haggle accordingly.
Now back to the beginning - let's assume that you're lucky enough to have found an engine that you're allowed to see operating in water before you purchase it. If it takes more than 3 or 4 pulls to start it, the owner hasn't kept it up much in my opinion but don't turn and go home yet. The fuel could be old, or things could be out of adjustment. Once running for 2 or 3 minutes, shut the engine down by pushing the throttle lever all the way off, then put it up about half way. Give the cord another pull. A warm engine should start up immediately on light throttle and no choke. If it doesn't, you may have fuel delivery problems though not likely something you can't repair; use this "poor starting" as a bargaining tool.
Once running, water should come pouring out of a hole on the bottom of the head within 5 to 10 seconds or so. If it does not, and if the prop is still on the engine (or it's in gear if there is a clutch), recommend that the seller remove the prop (or make sure the clutch is in neutral). Water turbidity in the running tank can and will prevent cooling water flow, and we don't want to confuse that with actual cooling system problems that you're checking for.
The smaller (40 series) engines won't always pump water at very slow running speeds but should offer up a good pencil-thick flow at a reasonable running speed. The larger ones (Century series) might take closer to 10+ seconds to start pumping but should still pump water at near tick-over speeds. If on any Seagull, at medium or higher speeds, water doesn't come flowing out of this discharge hole steadily and thick as a pencil, you may have to deal with a clogged water jacket. That kind of work will range from a simple back-flush or a good soak with Diesel oil, up to having to remove the cylinder head. The latter is no small operation in all too many cases, so take note of this if you're not happy with the water flow.
Even if you're in the position of seeing your potential purchase running, ask to remove the spark plug and give the engine a rope pull or two. Do you hear any mechanical noises from the gearbox? Any unusual stiffness (given that there won't be compression with the plug out)? If so, there could be gearbox problems.
Even if the engine spins like a top and runs well, and if the seller is so accomodating, check the gearbox for gear oil. If there's fresh oil with no sign of milkyness, then that simply means that it's been changed recently. If it's dry or very low, one might have to consider that this engine hasn't been serviced well - after all, the seller should have checked that before shoving the engine into a bin of water. Same thing, if the milky-coffee-looking stuff in there appears to be more water than oil; regular changing should leave the oil emulsion still equal to regular gear oil in consistency, not run out like thin penetrating oil. Simply take this under advisement because any lubrication is better than none, and you might only have to give this the needed servicing... or consider it as you formulate your price offer.
Additons/corrections/comments welcomes. This was a rush job and just off the top of my head from what I'd do if I saw something on Craig's List.
There is nothing so useless as doing efficiently that which should not be done at all.
- Prof. Peter Drucker