Saving Old Seagulls

Hello,

I'm a new Seagull owner, and tested my Seagull (1955 40plus) for the first time last weekend.

Not being quite sure what oil:fuel ratio to use, I started with a 1:10 ratio, thinking this would be safest, and I could try more 1:20 later if this proved appropriate.

What I have found is that the engine starts - with a little difficulty - and runs reasonably smoothly. But what is noticable is that it really seems to need the choke closed even when fully warm. When the choke is opened, the engine falters and dies. I noticed that this was more of a problem when running in my dinghy than in a test tank: I wondered if this was because the engine was under load, or whether it was because the exhaust outlet was a little deeper below the water than is recommended.

I'm assuming that needing the choke closed indicates the engine wants a higher fuel-air mix than is delivered with the choke open. Could this be because the oil-fuel ratio I'm using is too high for this engine. Or that the carb needs some attention.

What would experienced Seagull owners check in this situation?

Thanks in advance.

James

I had a similar problem with my century. That was because one of the jets was blocked. As far as I know, you should only have one jet but, given the age of the engine, it might be a bitsa. Sounds like carb to me but I'm sure better minds will point you in the right direction.

Simon

Simon is on the right track, your motor only runs on choke because it isn't getting enough fuel. Either the needle isn't adjusted properly (adjusting screw level with the slide top is a good starting point) or the jet is blocked or restricted.

Steve

Thanks for the advice.

I gave the fuel system a bit of a service as a result - finding and removing lots of muck in the tank, pipes and filters in the process.

On reaching the (Villiers) carb, I found the needle - a number 3 - screwed way down. So I brought it back up to the top of the slide as recommended.

On reassembly, with the moor in a test tank with drivespring removed it started first pull and ran very sweetly. I spent the rest of the day going on about the wonders of Seagulls, their simplicity and user-servicibility to anyone who would listen.

But later in the evening with the motor in my dinghy it was another story entirely. Frustratingly I couldn't get it to start at all - at any combination of throttle or choke - despite an excellent spark being present on the plug. Eventually, I gave up, took it home and returned it to the tank where the same problem persisted. I finally did persuade it to run by warming the sparkplug with a blowlamp - and it then ran quite happily.

I'm planning to try again today with a bit more attention to needle settings and oil-petrol mixtures, but I wondered what others thought about these symptoms.

James

Also check the compensating jet hole which runs from an offset hole in the intake area to the top of the brass jet tube inside the carb.
If the carb has been dismantled, look into the carb from the top, and check that the end of the small loctation screw holding the brass tube in is sitting on a small ramp milled into the top flange of the brass.
This is to ensure that the compensating jet hole in the carb body lines up with the passage in the brass jet. If this passage is blocked or out of line it will affect the running of the motor. Rick

Just to say that after another check of the carb, and fuel mix the Seagull started on first pull yesterday, and I took my 13' dinghy on a trip on the tidal Thames - for much of the time against a pretty ferocious outgoing tide. They certainly do have lots of thrust, as is often remarked.

There were a few moments when revs dropped suddenly and unexpectedly, making me fear the worst - but each time the engine picked up again. Propably just the prop hitting a stick or other flotsam I'm suspecting. The river's full of it at the moment.

The only real mishap was that a significant fuel leak appeared as the carb bowl became loose as a result of vibration. Entirely my fault for not doing it up tightly enough after taking everything apart. I've learnt my lesson in this respect.

But as a result I didn't get to measure fuel consumption as I'd planned. I'll do so in due course - but in the meanwhile I'd be interested in what others find is typical fuel consumption for 40-plus models working reasonably hard. How long does a tank of fuel usually last?

James