motor runs, prop turns not

[Ga]

In question, CP longshaft, new to me. I added transmission oil, gassed her up, spun the starter...The motor runs but with minimal turning of the prop.
With the motor lying down on the hard, I turn prop and it feels as if there is no connection to the top end (starter cylinder not turning) and no noise. When I turn the motor on her side or back and turn the prop, there is a clicking sound from the shaft, above the differential, about where the two horizontal slots are. Transmission oil is running out the horizontal slots. So is the drive shaft busted or what? Do I split the transmission case, remove the lower shaft housing? Buy a book?

[Ga]

After posting, I split the transmission case. The driveshaft is OK, but the ring gear is not meshing with the pinion, except, of course, when the motor is lying on its back. It seem that the gears are not meshing because the prop shaft has too much endplay, as if there were a thrust washer missing between the ring gear and the propshaft bearing in the transmission casehalf. I suppose the next step is to pull the propshaft, see if the teeth on the gears are eaten up.

[Ga]

Later, I pulled the propshaft. The gear teeth have some surface corrosion but otherwise look OK. On the dissassembly bench there appeared a machined washer that fits the shaft. I think perhaps the dissassembler before me installed the washer OUTSIDE of the transmission-case, between the brass pincollar and the propeller. Yes? Assuming so, I installed it INSIDE, between the ringgear and the propshaft-bearing in the transmission casehalf. Now the propshaft endplay is about 1/16 inch, the gears mesh and all looks well. However, the transmission-case gasket did not survive dissassembly. To me it looks like 1/32 inch black gasketpaper: do I need something esoteric and waterproof? Obviously, the thickness of the gasket will affect the total endplay of the propshaft, increasing it to 3/32 inch. Finally, are the allen-head machinescrews holding the transmission-case together SAE or some ancient British standard?

[Ga]

I put her together but things are still not right. It seems that the endplay is still large enough that the gear teeth are "riding" over each other--the symptom: as I turn the motor by hand, the end play disappears totally, propshaft stops moving, motor becomes hard to turn, then there is a "release", the endplay reappears and motor and propshaft then turn easily, repeat. So it seems to me that I need a thicker thrust washer inside, or...

Perhaps the thrust washer goes OUTSIDE the transmission-case, between the brass pin-collar and the rubber washer/seal? One could see how that might press the seal against the housing for a tighter fit, but wouldn't the rubber quickly wear right away, with a thrust washer riding on it?

The threaded holes on the lower shaft-housing appear to have been welded and re-tapped, so I suppose their thread specs will have to be determined by experiment and inspection.

[CatiGull]

Ga - you definitely should get the correct manual for your motor to make sure you can put right what someone has probably messed up in your gearbox

The fittings are indeed British Whitworth (non-SAE or metric)
On edit - corrected to BSF by Charles below...sorry
which are readily available too....although again one has to be careful someone hasnt forced an incorrect fitting into Aluminum and further made things nasty

[charlesp]

Catigull is quite right - you need the manual!

John at SOS can supply you with one - and he will have a stcok of thrust washers too. There were various sizes available, and I'm sure he can help.

He can probably supply a gearbox cap gasket as well, leaving you with only the threads to worry about...

[John@sos]

I wonderif you are one of the dozens that have bought a manual from me recently? However I have only sold a few to the States, where I guess you are!!!

The thrust washer that keeps all in mesh is a hardened steel flat washer and should be found stuck on the back of the Crown wheel with the oil, when you take the cap off. There were three thicknesses, plus shims, to ensure the gears correctly mesh.

hope this helps.

Regards,
john
SOS

[Charles UK]

All the threads used by British Seagull in the lower units are BSF ( British Standard Fine) not Whitworth & are not easy to get here in the UK.
The only Whitworth used by Seagull are the 7/16 transom screws.
I'm sure John has a stock of all the lower unit screws & bolts certainly in plated steel as Seagull supply but also in stainless which save so much later trouble.
The other Charles was talking of producing a table of all the fastener dimensions used by British Seagull in their readily available outboards in his "Encyclopedia of Seagull products & their history" which we all are waiting for with baited breath.
I would recommed before anyone cleans a thread up with a tap or die that they check that they have the right thread type especially on a motor that was produced after 1980 as the 170, 125, SD160 & SD110 were produced using a mixture of BSF, Metric, BSP, & Whitworth but only on the transom screws.
After that the QUB range tended to use Metric for just about everything above the water line, except the water fittings BSP, flywheel nut BSF & the Carb & exhaust tube, BSF & BA.
I do hope you havn't ruined your gearcase by running a 1/4" Whitworth tap through the 1/4" BSF threads but sleep easy, Seagull & John will probably have new castings in stock.

[Duane A.]

The best chart showing thread sizes that I have found to date is on Yahoo - Britsih Seagull Owners UK Group. Join and check under files and you can pull up a chart that is fairly complete. Thanks to the people on this group that have helped make this chart as good as it is so far. You get some nice information on this Yahoo site, but my hat goes off to John at SOS for all he does for us Seagull people. Both by sharing his knowledge and access to parts both new and used that are hard to come by otherwise.

[CatiGull]

Charles - thanks for setting me straight on the fasteners - I thought Whitworth described the British thread system and BSF was a subset of WHitworth fasteners, but am obviously wrong on this one.

There is an outlet for BSF here in Lyons NY...isnt that wierd....

BRITISH TOOLS & FASTENERS, LLC
7696 ROUTE 31, LYONS NY 14489
sales@britishfasteners.com
TEL- 315 946 9400 FAX - 315 946 9344

I might be able to stop in next time Im travelling out there this week.

John - are there any strange sizes on 'Gulls that are hard to source??

[RickUK]

Just a couple of thoughts from me - early Seagulls are easy to deal with thread size-wise being predominantly BSF, but as Charles says, the later Seagulls are a riot of imperial/metric sizes, which I've been discovering through rebuilds on a 170 and a Curlew.
For hex bolts, the first easy check is to put a spanner on and see which fits - a 13mm spanner on an 8mm bolt, or imperial sizes on their respective bolts.
Whitworth spanners fit BSF bolts correctly but they are out of step - eg. a 1/4" Whit. spanner is used on a 5/16" BSF bolt.
3/16" BSF is rarely listed anywhere, but 2BA bolts/screws are the same thread pitch (only used I think on the exhaust tube screw and on the Villiers magneto fixings).
A personal foible but maybe worth mentioning - whenever I am using a tap to clean a thread - especially a blind hole - I use the tap in an uphill direction so that any corrosion product can fall out rather than have the tap chewing round in the stuff - not doing the thread any good and probably shortening the life of the tap. I like to find HSS taps, but carbon steel ones are cheaper and perfectly good enough for thread clearance. Rick.

[RickUK]

Hi again Ga. I've just been re-reading your original query, and think we may have gone off at tangents.
After the discussion about threads etc., having seen your mention of welds - retapping etc, I imagine it is likely that someone will have used freely available thread sizes, so they may not be the original sizes we have been talking about. The only check for this is to get the bolts you have checked with a thread gauge, or try nuts of various pedigrees to compare.
You are on the right track with the thrust washer - the only exernal parts (behind the prop) are the brass collar, and a rubber washer between the brass collar and the gearcase.
The thrust washer goes between the backside of the crownwheel (ring gear to you I think) and the thrust face of the endcap bearing.
This is a hardened and ground washer, and as has been said, there are often one or two additional shim washers to adjust backlash. The gear quality is not wonderful, and they will have a wear pattern by now, so a fair amount of backlash is acceptable, though I am at a loss to explain why you should get a reasonable amount of backlash, which then gets lost! Is there a build-up of rust between any of the teeth which is giving you a false feel?
John of this site can supply you with thrust washers and new gaskets for the end cap - the gaskets were originally brown and probably about 10 thou thick. I guess the black one you describe was homemade by the guy who has been in there before. Rick

[Ga]

Thanks, all, for useful knowledge.

Rick, the looseness of a gear is its lash (sideways wiggle, right?).

Whereas endplay of a shaft goes in and out.

So the propeller shaft will have both endplay and lash, both adjusted simultaneously with one thickness of thrust washer(s). Is there a number for lash or endplay, or is an intuition developed?

Ga

[RickUK]

Hi Ga - yes, backlash is the side to side free play, and endplay is the back and forth (axial) float, but you can only set both by adjusting the end float via the thrust washers.
There are no set amounts as far as I know, but some detectable end float is desirable, and the important thing is that the gears don't lock solidly together. Rick