forty water circulation no 2

[headdownarseup]

All looks fine and dandy there.
Not too much of a difference between the FP box and the LS box.
Going back to the FP box for now (if you've still got it to hand) look at where the prop shaft comes out and you might see a round "flange" cast into the outside of the box just where the brass collar sits. Immediately behind this there should be a rubber grit seal (washer).
On the LS box there is no cast "flange" so you can see everything. Replace your washers with a rubber washer x1 (grit seal).
There will be a little bit of in/out play on the shaft. (maybe some side to side play too) Any more than 2mm (1/8th") in/out, it might need some thrust washers replacing INSIDE the box. This refers to the back lash on the gears inside the casing. If you can remove the end cap to have a look inside GREAT, but if you can't dont panick.
Fill it right up (and i mean right up to the brim) with oil and see how it goes.
It should work quite well. Props will of course swap over with no issue. Pick and choose the best of the bunch and go testing.

It'll soon be making smoke and noise and pumping water for another 30 years.
Stick with it, nearly there.



Jon

[Charles uk]

Why right up to the brim Jon?

[Grumpy]

Headdownarseup, Will do as you say re the gearbox. Did notice the rubber grommet sunken into the outer facing on the FP box and couldn't see any way to attach anything similar to the LS box. Could that indicate an increase in oil leakage from box?
Will be paying more attention to inside and outside definitely..

[Grumpy]

Gotta ask another question.
The rear caps for the gearbox( with the filler plug) have different holders for the shaft.
The LS is a complete tube with full brass but the FP like all my silver centuries has a gap in the brass tube topside.
Is there any purpose for that? Efficiency or cost saving.
Promise to try and not ask any more questions.

[Hugz]

Why right up to the brim Jon?

Jon probably means when the motor is in an upright position.

Have you noticed that there are about 4 visitors or more to every registered forum member that read these posts??

Does the view number per thread include visitors?

[Grumpy]

Its after 6 pm , finally had the gull working in the test tank but I have to get inside before all the horrible night creatures come crawling out and kidnapped me or flogged all my gulls.
The FP went well and with a heavy hand on the accelerater passed water. As of old never a world champion in that area.
At last. Not like brand new but enough to calm my unsettled soul.
It did run a tad hotter than before but I reckon I know the answer on that.
Definitely needs a good hard run which I plan for next week.
Everyone who has given advice can have a drink on me
Cheers.

[headdownarseup]

Chas.
Why not to the brim! A direct drive box has no clutch to worry about internal pressure increase/decrease. Also helps to keep any water ingress to a minimum. More oil is always better than no oil. True, they will leak some oil OUT when in use. Oil is still cheaper than replacing bushes and gears, if a little messy to re-fill through such a small hole.

A clutched box on the other hand will need an "air gap" or breathing space inside for the shaft to move backwards/forwards thus engaging/dis-engaging the drive.

All of these gearboxes are cooled very well whilst in water and any expansion internally (which is what i think you're concerned with there) will be kept to a minimum.

I'm not suggesting for one moment that others do as i do, but with any old gearbox it will leak to some degree.It is after all the way these were designed. The more these boxes become worn, the more oil they will leak.
Damage limitation is all...


Jon

[headdownarseup]

Grumpy

A hot engine doesn't always spell disaster. Have you made sure the mixture setting on the carb is not set too LEAN. (could explain a few things here)
Are you using 10:1 or 25:1 in this motor? A new plug too might not be a bad thing either. Might as well. Double check the points gap while you're there.

Did you take any pics of the inside of the end cap. The only thing that springs to mind is perhaps what you describe as a "baffle" cast into the cap?
There are on some of them an oil slot cut into the bronze bushing of the end cap. (is this what you mean?) Whereas in later types the end cap bush changes slightly in appearence to a "cutaway" to provide oiling requirements. Some with a baffle, some without.
Pics will help here


Jon

[Grumpy]

I always use 10-1 in my gulls even the ones I have exchanged the jets inside the amal carbs eg silver centuries.
Don't want to take the risk.
2 x 25-1 I have are a GFP forty plus with a bing carb and my latest the EFPC 1978 with Villiers .
Actually use 20-1.
My lack of correct mechanical terminology is very annoying , esp to myself, but yes I was referring to the gearbox cap with the cut away bushing.
Used it because I reckoned they usually change things over time for good reason.
Then I did 2 other things,
Replaced the LS gears (35 teeth) gear plate off the gear box shaft , a solid plate meaning oil has to circulate up and over with the same plate from the rejected FP gearbox which has 2 large holes allowing oil to obviously circulate inside the gearbox far quicker and directly and efficiently.
Now that is clear as a bell to me but I only wish I could communicate using correct terminology. The grim reaper reckons its too late
Yesterday ,at the moment I was working out the amount of play I wanted on the prop side of the gearbox a friend , more mechanical than me turned up and insisted I have no gap at all between the prop and the gearbox outer end , nice and tight, and that it would work itself in:.
I foolishly backed of , still wonder why I did, found it ran too hot for me, obviously a massive drag on power,
Then altered it this morning so it runs sweeter ,certainly less than a 1/2mm gap, tepid and easier throwing out the water. Good enough for me.
Did have a problem with leakage from the back of the gearbox which I have overcome meantime (with a smile I realise my chances of setting any seagull speed records have been severely restricted due to increased water turbulence to the prop) but will require the top screw hole in the gearbox rear cover being rethreaded
Overall one happy chap although I would not want someone of your mechanical skills and no doubt steely disapproving grimace at such barbarism within a bullsrush.
Will give her a new d16 soon.
Thanks again. Cheers.

[Charles uk]

Jon
The reason that Seagull recommends filling the gearbox to the bottom of the filler plug when the motor is vertical, is probably oil drag.

We are talking a low tech, low output, power head, using a viscous gear oil in it's well cooled lower unit, it would be logical to assume that completely immersing the pinion & crown wheel & therefore removing any possibility of any air entrapment in the lubricant would make it more difficult to stir, & it's not a difficult job replacing the pinion bush & the prop shaft bearings, though there is a significant cost, when restoring your pride & joy.

Most Seagull racers don't run 140 oil in their unsealed boxes but use 80/90 instead, as the increase in performance is noticeable.

Whilst your argument is perfectly logical, I'm not sure any of us can afford the possible loss of push on the back of the boat, strangely enough Seagull's dyno didn't measure the power output with the gearbox fitted, though the lbs of thrust transom bracket with the built in spring balance did, when it appeared in the mid 80's, right in the middle of the sealed gearbox era!

[Gannet]

I am reluctant to move this post away from its topic, but following Charles and Jon's discussion on gearbox oil quantity, i would like to add the following in respect of the smaller Forty series gearbox in FV, LM, SJM, etc
I am sure that we have all seen an example of these smaller gearboxes wrecked by a lack of oil.
Taking Hugz's comments on the number of guests visiting this site, who might not appreciate the importance of having plenty of oil in these smaller gearboxes .
British Seagull Operating Instructions booklet for the Model Forty (FV, FVP, LS,SJM & SJP) states quite clearly:-

LAY THE ENGINE ON THE FLOOR WITH THE TANK DOWNWARDS, REMOVE THE PLUG , AND FILL TO OVERFLOWING.

Now this instruction might have been changed for later models, but for these smaller boxes taking approx 65ml of oil it is the best and the recommended method. Additionally I believe that screwing the Plug in will force new clean oil into the clearance between the pinion shaft and its bearing, thus pushing the water or emulsion out to prevent corrosion during storage.
Experts here might debate whether the bigger FVP, LS, SJP boxes should be filled in this way, but I am not taking sides on that discussion.

Jeremy

[John@sos]

Just to add a footnote to the bit about the location of the water delivery pipe.

The cutaway model had been put together by the villiers apprentices and they got it wrong!

I published it with a note to say can you spot the deliberate error. Di not take long before someone saw that errant pipe!

Just another point that has come up in this thread. How full to fill your gearbox.

When those motors were new filling them to the brim would not cause any problems... However, after 25 years or so you fill it to the brim then stand it up the oil will pour out of the worn bearing behind the prop! oil in the boot of the car, bottom of the dinghy if you haul it in, the garage floor if your stand it up right for storage, (strapped in place or on a wooden board!!).

In short, only fill Seagull gearboxes half full or the mess will take forever to clear up!

Regards,
John
SOS

[headdownarseup]

Good point John, but as the vast majority of these gull boxes will almost certainly have had dubious maintenance carried out on them over the years,
THIS, coupled with hard useage results in what we see today with a HUGE number of second hand boxes being wrecked through having no oil in them.
Nothing new there really with any old seagull someone wants to renovate. The bigger challenge is to try and bring everything back to as near as "as new condition" and still remain as reliable.

Internal drag may have some bearing in this argument, but quite honestly the power difference to most people will be negligible at best.(racing aside for the moment)
I prefer to have too much oil in my gears rather than not enough, (as does Jeremy) sure it get's a bit messy at times but my motors dont get used every day of the week.
Lucky if they see water 3 or 4 times a year for most of them if i'm being honest, BUT i'd still rather have a well lubricated gear case all the same.I just drain off the excess oil to avoid any further mess when the motor gets put into storeage.
Each to their own.

Interestingly i've been doing some research with oil additives and friction modifiers at work (just because i can and i have access to it)
Some quite good results, but whether this has any relevance in a seagull i''ll leave up to you to decided.

For those interested, take a look at BG PRODUCTS.


Jon

[John@sos]

Put as much oil in as you like, so long as you clear the mess up after! Dubious mantenance means they are normally bound to leak like sieves!

If hung vertically, as they should be, you WILL need a cut up plastic container, tied on, to catch the excess!

You are right, it makes very little difference to the power output, not noticable.

I also advise owners of the sealed gearbox models to use 140 oil when the lip seals go, at least until they get round to replacing the seals.... Bevel gear one is a arkward one to do.. So in my experience they tend to stay on 140 grade for a long time and no ill effects!

regards,
John
SOS

[Oyster 49]

Personally I would go with John and Charles advice. They are by far the most experienced and knowledgeable here. Whilst having more oil in the box will improve the lubrication, most of it will end up on the floor.

Keep the oil fresh and topped up regularly, particularly on the smaller gearboxes. Overfill and have it dripping everywhere is just a bodge in my view. As long as there is some in there and it is changed fairly often all will be good.