Engine runs great - Prop not turning

[DerekKing]

My Seagull - runs great - starts near first time - carefully tended since I got it with my first sailboat near 2 years ago.
As of last week - now prop not turning. Have had the prop off (now twice) and all seems OK. Rod which runs from drive/neutral lever to clutch fork is now bent due to over aggressive operator. I have managed to pull clutch fork past stop shoulder.
I have had the pin out again on the bench - it is sound.

Serial # EFPCL514A4
Q - is there another shear point anywhere in transmission?
I am about to start further dissembly and will appreciate - where should I be looking - Appreciate any inputs -

Derek
Stranded Brit in Spring Texas.

[rosbullterier]

Warning - after writing lengthy reply to you - this stupid forum site lost it. No wrong buttons pressed - it just bloody disappeared. This will shorten my help quotient mechanism . . .

You seem to be saying the clutch fork is jammed up on the gearbox shoulder. This would disengage the propeller shaft inside the box, allowing continuous free movement.
After removing split pins, the long operating rod can be unscrewed from the bottom fork and straightened.
Not sure which pin you refer to. Does it fix the bronze collar to the shaft?
There isn't another shear point in the transmission. It's far too agricultural for anything so sophisticated. The clutch worked before, does the engine turn now and turn the prop shaft or turn without the prop shaft turning?
I don't know why you are looking for another shear point if you say the shaft is not turning.
However, I know sod all about any engine made after 1970.
Come back.

[Charles uk]

I think you might find on inspection inside the gearbox that the clutch dog is spinning on the prop shaft as it's broken the shear/retaining pin that holds it, so RBT is right it doesn't have one, "now".

The oil in this gear box should be EP 90.

This is what can happen if the revs are too high when engaging drive.

[rosbullterier]

But Charles (and don't forget I know nothing whatever about these later boxes), Derek says the prop won't move rather than is spinning free.
He says he has removed a pin, so presumably this is an external pin - he hasn't dismantled yet.

[Charles uk]

Take it to bits & it will become self explanitory.

[DerekKing]

Episode 2 - Have removed the clutch fork and items behind prop hub - shaft bare that side. Drained oil out gear box, then removed dome gear case cover. Crown gear and pinion both sound, also the pawl faces. other than the oil/water emulsion, no metal debris or distressed surfaces. Crown gear spins free on prop shaft. There is through hole in crown gear but no pin - I assume hole is for lube.
Pinion gear spins freely. I have pulled on starter cord and engine/flywheel turns freely - but not the pinion gear. Seems I have "gap" in the drive shaft - yes?

Apology - my previous statement "Derek says the prop won't move rather than is spinning free" should have stated turns free - but engine does not drive.

Which is the best next step joint to "separate" between the engine and gearbox. I seem to have a seized bolt where the shaft tube connects to gearbox top.
I have full set of correct "old Brit" wrenches.

I REALLY appreciate your assistance - Thank You - Derek

[40TPI]

No replies............. Probably all out enjoying the wet and rainy Bank Hol..........

I know I'm repeating myself but the most powerful tool on this forum is the search feature at the top of the page which allows you to trawl back over all the posts and topics that have gone before to find out what advice, wisdom, tricks and tips are appropriate to your problem.

From what you have discovered I'd say it's odds on the square section mild steel drive shaft has corroded into two halves; hence motor turns and bevel pinion doesn't................

This usually occurs just above the water pump housing so you will most likely have a long section still attached to the end of the crankshaft at the top and about six inches attached to the pinion shaft on the gearbox. The seized pinch bolt is not your problem and it doesn't help you at all to remove it.

The power unit needs to be un-shipped from the leg by removing the two 5/16 nuts on the studs going through the flange on the top of the drive shaft casing. Searching back you will see that this can usually require an obstruction spanner to remove the nut between the exhaust tube and the casing, or some other ingenuity or a dose of luck that the last person didn't tighten them up..........

Remove the power head with the silencer/exhaust tube still attached; leave it on. ( It will slip off the top of the exhaust/water pump housing at the bottom with some gentle waggling/jiggling ....... take care not to bend the water delivery pipe inside the exhaust too much.) You will likely have a rusty section of drive shaft stuck to the end of the crankshaft to remove.....
This may come off easily but if it turns awkward … some of my earlier pics in this thread:
http://www.saving-old-seagulls.co.uk/fo ... 8436#p8436

To remove the lower end of the rotten drive shaft tube you will now have to split the water pump housing from the actual gearbox to recover the water impeller and get to the end of the pinion shaft..... this is not the most welcome task on a Seagull........

Have a look at this recent thread ...........
http://www.saving-old-seagulls.co.uk/fo ... 714#p11714

There are quite a lot of other posts on this in the past and I'm sure RBT will be along shortly to sponsor the use of MIG welders.......




Peter