LEAKING GEARBOX

[grahamcamm]

I recently posted a thread about my recenctly aquired seagull had the gearbox full of grease instead of oil. I have since cleaned all the grease out and replaced with 140 gear oil. I've since run it up in the wheelie bin but noticed the day after gear oil floating on the water and have had to top up the gearbox as it was only half full which seems a lot after only 5 mins running. Will it just be a case of replacing the old paper gasket or is there another seal where the drive shaft enters? Thanks in advance

[skyetoyman]

I had the same problem. The grease was hiding a missing old seal. The gearbox gasket will need replacing also.
remove the prop . A thick brass washer on the shaft will need its pin tapping out and behind this should be an oilseal.(mine had vanished)
SOS has both oilseal and gasket available at very reasonable postage.
smearing a little oil on the gasket surfaces prior to fitting the gasket is usually a good idea.

[skyetoyman]

Another thing. The only way to remove all the grease is to remove the crown wheel and shaft. To do that you must remove the thick brass washer and pin.
Best of luck. It is not rocket science as a seagull is built like a brick toilet.

[grahamcamm]

So if I fit a new paper gasket and propeller shaft oil seal should that be enough or is there another seal where the drive shaft enters? ps engine is a WSPCL

[charlesp]

It may be a good idea to confirm that your problem is in fact related to oil seal/gasket. The oil seal is more of a grit seal, and does little to prevent oil leakage. If the gasket is faulty you should be able to see where the oil is leaking from.

Have a good look to see if there's any play in the prop shaft bush. Wiggle the shaft from side to side - if there'sw any movement there's your problem.

Does the gearbnox only lose oil when it's running?

[grahamcamm]

It may be a good idea to confirm that your problem is in fact related to oil seal/gasket. The oil seal is more of a grit seal, and does little to prevent oil leakage. If the gasket is faulty you should be able to see where the oil is leaking from.

Have a good look to see if there's any play in the prop shaft bush. Wiggle the shaft from side to side - if there'sw any movement there's your problem.

Does the gearbnox only lose oil when it's running?

Yes, the gearbox is only losing oil whilst running. There is no sign of oil running out of the gearbox when the engine is stopped/stored in the garage.
When you say wiggle the prop shaft, do I need to take the propeller off or can I just hold the propeller and see if there is any play that way?
Is the prop shaft bush easy to replace and is this part easy to purchase?

[Todd]

Take the prop off, punch out the pin and remove the brass collar and old seal. Clean everything up and give it a good examination. Carefully file any burrs from the prop shaft. Check for side to side play, there ideally is none, however it's normal to have fore and aft movement. And no, there is no seal on the drive gear bushing. If you're content with what you find, install a new seal, put it back together, top up the oil and try another bucket cruise.
I suspect that, for one reason or another, you originally thought the gearcase was at the correct level when in fact it was not. And that most of the oil you saw the next day was actually that which drained from the exhaust, as Seagulls are wont to do.

At least if it was my motor, that's what I'd be hoping for.

[grahamcamm]

Thanks for the replys chaps. Todd if there is play in the prop shaft is replacing the bush an easy job or a pig?

[chris]

does that mean that all of my 9 seagulls are faulty because they all leak oil out of the gearbox, I thought they were designed to run on a oil water emulsion

[charlesp]

does that mean that all of my 9 seagulls are faulty because they all leak oil out of the gearbox, I thought they were designed to run on a oil water emulsion

Not at all!

All my repairs go out witha couple of sheets of paper - one is a report on the particular motor, with dates and suchlike. The other ends with the statement ' ...if it doesn't leak oil it's not a real Seagull'

[Todd]

Thanks for the replys chaps. Todd if there is play in the prop shaft is replacing the bush an easy job or a pig?

I can't answer that, I've never done it. But, there must be a bunch of guys here who have. If, after a thorough check-out, you're convinced the bushing or bushings (sorry-must be an American thing) are indeed bad, give John at S.O.S. a call. He'll be able to give you the cost, availability, degree of difficulty, perhaps even a different option altogether.

I'd be interested in your results.

[grahamcamm]

Right, I've took the propeller off. Next was a collar with a hollow pin, then there is a large washer and other than the selector is nothing else. The shaft other than having slight movement backwards and forwards is solid sideways and up and down, no play at all. Where should the oil seal be? There was old thick dirty oil present but no sign of a fresh leak. When I removed the original offending grease I didn't replace the paper gasket before I put the cover on, I have since put a new gasket on. Is it possible for the gear oil to have been leaking through there before the new paper gasket was fitted? Like I say though, I didn't see any oil seal.

[Charles uk]

There were no oil seals in Seagull gearboxes until the FPC in 1978, by that I mean a proper rubber type lip seal. If your gear box uses 90 grade oil it's got these seals.

Prior to this all Seagull gearboxes that ran 140 grade oil were designed to lose a small amount past the bearings, "dry bearings are not happy bearings", & if they let oil out then they will let water in, hence the use of an oil that will emulsify.

If there is a large quantity of oil leakage then your pinion & prop shaft bearings might be showing signs of wear, & after 30 + years that should be no supprise.

I've owned 40 year old seagulls that leaked like mad, but still ran quietly & smooth they just need topping up every time you use them & much more frequent oil changes to stop the gears rusting whilst they hibernate.

If the puddle they stand in peeves you, add a teaspoon of grease to the oil, that should increase the viscosity enough to slow the torrent.

Changing bearings is an expensive & often a difficult wrestling match, you would get change from the cost of the bearings, if you bought 20 litres of 140 instead & just kept topping it up.

Non sealed boxes were designed to have a 10 thou paper gasket under the end cap, this with the thrust washer gave the proper clearance to the crown wheel & pinion gears, after 30 years use the washer & the thrust face of the end cap bearing might well have worn a bit, if the gears are noisey, try without the gasket to see if that cures the clicking when turned by hand, if it does then seal with a wipe of thick grease or a thin layer of RTV silicon.

[Todd]

With no sideplay and a new end cap gasket, I'd say you're in good shape. Yup, oil would weep out of the seam without the cover gasket, but more to the point, water, being much less viscous, would leak in.

There is a rubber washer-like grit seal which goes behind the brass collar, but don't expect it to stop oil weepage. It won't and wasn't really expected to. If I ever find a proper oil seal which has the necessary o.d. and i.d., I'm going to try to fit it just to observe the result.

Put 'er back together, check the oil level one more time - (140wt gear oil filled to the bottom of the hole with the motor standing upright - you knew that, right?) and enjoy your 'Gull. Check the oil level and consistancy often.

[skyetoyman]

How close would this one be


http://cgi.ebay.co.uk/ROTARY-SHAFT-OIL- ... 5d27d93094