British Seagull motor rebuild?

[Chris152]

Yes, D16 is the other plug the bloke said was good for the job.

On the gaskets, am I right thinking

A is the cylinder head gasket;
and B is the engine block gasket?
C is the crank case join according to the video I watched yesterday - which showed it being re-sealed with goo.

AND - can the goo that's used in place of gaskets work instead of a cutout gasket? Just wondering in case going ahead and separating the block is an option - it'd be nice to take it apart completely, but not if we can't put it back together properly.

 

[dynax]

Hi Chris, i have 2 seagull motors, and i would advise against stripping down too far, there is no need really, when i got mine, i left some neat petrol soaking in the cylinder head for a while, replaced the spark plug, checked the points, and after a bit of clean, tank, carb, pipes etc, put it back together, put some fuel in, and it went on the fourth pull, just make sure you have it in a bucket of water before you attempt to start it, it needs the water to cool down the engine, good luck with it,

forgot to mention, get some fresh gear oil in it too, i think it's EP90, but double check,

 

[novocaine]

Head, base, crankcase. In that order. No reason to seperate unless it's a rattling like a bag of spanners once running.

 

[novocaine]

Sae140 not ep90. Close though and wont really make much difference.

 

[novocaine]

Do you have a multimeter?
Pull the ht lead of at both ends and test it for continuity. Do the same with the lt wire. Till ypu have a spark it's pointless looking at anything else. Have you do the screwdriver spark test?

 

[Chris152]

I did toy with the idea of mounting it alongside my little 4stroke 2.5hp Yamaha, but on a 12ft inflatable there wouldn't be a lot of room. Maybe on a kayak instead? It's light enough.

i would advise against stripping down too far, there is no need really, when i got mine, i left some neat petrol soaking in the cylinder head for a while, replaced the spark plug, checked the points, and after a bit of clean, tank, carb, pipes etc, put it back together, put some fuel in, and it went on the fourth pull, just make sure you have it in a bucket of water before you attempt to start it, it needs the water to cool down the engine

There's a dilemma. We got into this so my son could dismantle and rebuild an engine, I don't think it mattered to him what the engine was for. The more I think about it, the more I want to use it. We have a kayak, and have talked about building a canoe from ply. On one hand, it's about him learning how an engine works; on the other, it's becoming about using it. Pulling it all apart is about him learning; getting it working is about that but less so if we don't dismantle it completely, but also about using it (which I now really want to do!). Based on your comments, I reckon leaving the crank and block alone might be the way to go.
And SAE 140 it is!

 

[Chris152]

Do you have a multimeter?
Pull the ht lead of at both ends and test it for continuity. Do the same with the lt wire. Till ypu have a spark it's pointless looking at anything else. Have you do the screwdriver spark test?

No, would this do the job?
https://www.screwfix.com/p/lap-mas830b- ... 3godwg8EGA
tbh I was afraid of the screwdriver test, thought I might end up with those 20000 volts passing through my heart?!

 

[dynax]

yep, my mistake 140 it is, i haven't used mine for a while so easy to forget, i know what you mean about wanting to use it, and also as a project for your lad, if you get it running and all is ok then use it, but if doesn't run as it should then do a full strip down and rebuild, nothing to lose and also gets into problem solving first,

 

[dynax]

something like this might be handy https://www.screwfix.com/p/laser-ht-lea ... tid=424634

 

[novocaine]

Unless you have your hand on the engine or your feet in the same water you aren't getting a a shock. Remember that circuit thing? It may try to go to ground through you, a rubber mat will stop that. Also, safe side, dont hold the metal part.

That meter will do you fine. You can do continuity test with a 9v battery and a bulb if you havent got a meter and dont fancy buying one.

Having sat and thought about this a bit i think the simply stuff to rule out is the lead and caps by taking the cap off the lead ( they unscrew) cutting 10mm of the lead and fitting the cap back on. Both ends. Lt side test the wire. Points,plug, coils in that order.

 

[novocaine]

You dont need to pull it apart to learn how it works and i reckon hes getting a lot more from it by problem solving, i sat with a physist a few weeks ago, he could explain how it all worked but couldnt fix it if broke, (we were discussion suspension, dont ask why)

 

[powertools]

I did a long reply but some how lost it and have now run out of time.
The spark testers from Screwfix are of no use in this situation you would be far better of with something like this.
https://m.ebay.co.uk/itm/Ignition-Spark ... r=1&_rdt=1
You would be able to not only see if the plug is at fault or if the problem is in the ignition system.

 

[novocaine]

All of which would be solved with the screwdriver. Lol

 

[Andrewf]

I have a very rough and elderly seagull. Which I used lots in the 80's then replaced it with a nicer mariner. The seagull got chucked in the back of the shed and forgot about. About 5 years ago the mariner finally gave up the ghost, and in desperate need of an outboard, I dragged the seagull out. Took couple of days to clean all the cobwebs and sawdust off. New spark plug, some new gear oil bit of a clean and away it went. It's one of the old ones that runs on 10.1 so oil leaks everywhere. I have seen some brilliant things with seagulls, my favourite being watching one of my uncle's going past in his dinghy and filling the tank with some petrol. He must have spilt some as the next thing was it all on fire and he was trying to splash water on it to put the fire out. While the engine was still running and his dinghy careening about out of control.

 

[Eric The Viking]

From biking, I really like the NGK plug caps, the ones that don't take the Champion-style screw-on aluminium pimple on top of the plug. if the plug cap connects to the thread on the top of the spark plug directly it's one less thing to make a poor connection and weaken the spark. NGK caps also have a rubber seal round the spark plug's ceramic insulator, which is probably handy on an outboard.

IIRC, plug caps come in two sorts, one with a suppression resistor (to stop radio interference), and one without. You probably want the "without" version, but check your new service manual! Officially it doesn't make much difference, but with magneto systems, I think the simplest path for the spark is probably best. Replacing the plug cap is a cheap bit of maintenance, and goes a long way to giving you a solid spark at starting.

Also, if it's really old, replace the suppression capacitor ("condenser") across the points gap - it's usually a silver cylinder close to the points, probably mounted to the same plate. They do age - it might be fine, but a new one is one less issue lurking (and they shouldn't be expensive).

Obviously outboards get damp, so "tracking" of the high voltage down a path you don't want (e.g. across the cylinder head instead of through the plug), would be something to watch out for. Keep the high-voltage side clean, and water free (as much as possible), with Vaseline or WD40, although the latter is less permanent. If you can't get a good spark whilst holding the plug to the metalwork (with the HT lead connected to it and you with gloves on!), check in dim lighting in case it's tracking somewhere else at the same time.

 

[powertools]

All of which would be solved with the screwdriver. Lol

I did not suggest that the theory was incorrect but in practice trying to maintain a small gap between a screwdriver and a cylinder head while pulling on a starting rope to try and see a small spark is not going to work.

 

[Robbo3]

All of which would be solved with the screwdriver. Lol

I did not suggest that the theory was incorrect but in practice trying to maintain a small gap between a screwdriver and a cylinder head while pulling on a starting rope to try and see a small spark is not going to work.

I'm not sure to whom novocaine was replying but I took it to mean that the engine was easily stopped by placing a well insulated screwdriver across the plug & the body to earth it out.

 

[sunnybob]

If the plug is inserted into the engine and the engine is running, it cannot be stopped by earthing out the plug body, because the plug body is already earthed to the engine.

The sparking circuit (low tension or high tension) has to be interrupted to stop the spark. You can earth out the low tension circuit or rip the plug lead off. If the plug is heavily carboned then the engine can "run on" by itself as the carbon is glowing and igniting the fuel without a spark being present.

The "screwdriver trick" is a way of checking the integrity of the high / low circuit without using a spark plug. Its a quick and dirty "side of the road" trick to help diagnose a fault quickly (is it the plug? is it the points?). I've used it on motorcycle engines long before they had electric starters, so although tricky, it should still be possible to do with a corded pull motor.
Remember, youre not trying to spin the motor a dozen times to get momentum, you just need to get the ignition system turning over, something that on a small two stroke without a plug in, is as easy as it can get.

 

[novocaine]

1. Powertools. Screw driver trick for testing a for a spark, I've managed to do it on a **** of a lot of englne's over the years ranging from tiny little lawn mower 2 strokes to 500cc twin opposed westlakes, all of which had pull starts on and all of which I've managed to do it on, so yes, I still say you can use a screwdriver instead of wasting money on a gimick that does it for you. but hey, that's just my opinion, I wasn't blasting your suggesting, just reiterating something I said right at the start of this thread as part of me trying to help Chris and get his seagull running for minimal outlay. Also, thanks Robbo for coming to my rescue (using a phone at the weekend makes for difficulties in using the quotes.

2. Bob you are right earthing the body won't. but earthing the plug will kill the engine, the pixies are lazy and want to take the shortest and easiest path to earth, if you earth the nipple with something it will take that path rather than jumping the gap, it's how atcos and qualcast mowers were stopped for years. (piccy below shows the tab you pushed down to do it, never got electromucited doing it either). none of this is relevant here though as that isn't what I was referring to by saying use a screwdriver (see point 1) and you couldn't do it here anyway because it's an enclosed cap.

I've already said how you stop it, it's the British Seagull suggested method, yes you could put a "kill switch" in to the LT side of the circuit, something to thing about in the future, once it actually runs, but don't forget the choking it method, as one day that switch will fail (salt water sucks)

sitrep needed Chris, are you waiting on parts or digging in further?

 

[Chris152]

sitrep needed Chris, are you waiting on parts or digging in further?

Ha, yea I went quiet as lots of this went right over my head! The boy's not here for a few days, and the new plug arrives mid-week, I think. My cunning plan is to wait for it and him to arrive/ return, fit the plug and see what happens. Then, if that doesn't do the trick, we'll work back through the advice above. But - we're going to read through it together anyway - it clearly contains lots of info/ terms we need to learn and read up on.
It's great reading through the suggestions, if you all have the patience to keep responding to problems as they crop up I'd like to keep the rebuild here rather than head off to a Seagull forum.