Boat Maintenance & Repair Forum

alpha 1 G2 drive noises

by betty boop » 04 Sep 2017, 16:53

Doing some initial research into Alpha 1 G2 noises and drive lube possible 'leak'

symptom 1 ,is 6-10mm or so of drive lube lost out of the monitor bottle. Lube was new /changed in May but I think any air bubbles would have come out by now. Cant see lube oil leakage from shift or speedo seals and a vent & filler screw test shows no mayonnaise from a quick removal and put back. & would and sludge raise or settle?

number 2 - drive noises, we had 2 instances of thinking we were being shadowed by a helicopter. Stopped, no noise and nothing again as we pull away. Doesnt seem to be a gimble/u joint noise as is common on you tube as it was straight line travel but would such a fault be intermittent? I cant be sure about as I dont use it opened at at sea much.

Im thinking of a take it apart & pressure test but Im not eager to strip it down this close to the end of the season. - hoping there may be some words of wisdom out there? :D
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by Ianfs » 04 Sep 2017, 19:30

Shift shaft seal for the oil leak and the prop banging on the fin anode because it's loose will sound like the Coast Guard are on exercise above you. :D

If it's the shift shaft seal you might see a tiny bit of oil leaking from the tell tale hole at the bottom of the leg. Very little milky oil and its difficult to spot because the water through the tell tale washes it away.
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by betty boop » 05 Sep 2017, 09:00

Ianfs wrote:Shift shaft seal for the oil leak and the prop banging on the fin anode because it's loose will sound like the Coast Guard are on exercise above you. :D

If it's the shift shaft seal you might see a tiny bit of oil leaking from the tell tale hole at the bottom of the leg. Very little milky oil and its difficult to spot because the water through the tell tale washes it away.


thanks Ian - I dont have a fin anode - T'was changed for a flat one. I did have an inspection mirror up inside the shift shaft enclosure - it looked a bit weepy but no sign of lube leaking out so could be left over water from flushing etc. busy weekends through September are looking like the season is all but over so a strip down /pressure test may be the way to go. :cry:
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by Ianfs » 05 Sep 2017, 09:51

number 2 - drive noises, we had 2 instances of thinking we were being shadowed by a helicopter

I dont have a fin anode - T'was changed for a flat one.


Was it changed before or after the 2 instances? I'm guessing it was changed before the helicopter noises? :D Gimbal bearing and UJ's normally rumble and usually on opposite lock.

I did have an inspection mirror up inside the shift shaft enclosure


Not sure how you did this. The Shift shaft seal is inside the lower gear case. Hears a picture of an alpha one and although they are not exactly the same they have similarities in this area. This photo was photo shopped for someone else so ignore all the other indicators.

Lower gearcase housing showing possible leaks.jpg
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by BruceK » 06 Sep 2017, 11:38

On a alpha 1 I once overtightened the top cap of the upper gearbox. When cold it made no noise. Once on the plane the top of the drive is clear of the water and would get rather hot. This caused a bearing rumble that eventually gave way causing me to shed a gear tooth. Should that noise happen again get someone to touch the upper gearbox and check how hot it is before it submerges back into the water.
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by betty boop » 07 Sep 2017, 09:34

BruceK wrote:On a alpha 1 I once overtightened the top cap of the upper gearbox. When cold it made no noise. Once on the plane the top of the drive is clear of the water and would get rather hot. This caused a bearing rumble that eventually gave way causing me to shed a gear tooth. Should that noise happen again get someone to touch the upper gearbox and check how hot it is before it submerges back into the water.


not sure the top cap has been removed from the paint/bolt head condition but it may have so will look at this one - thanks but the more I think about it the more I think (and get paranoid over) the drive has had a major knock at some point, there is a large chunk out of the skeg (not by me) but nothing I havent done before. it just plays on my mind that 2 or 3 problems may route to one issue/one problem, the trouble is with minimal high power use I dont really get to trial the drive extensively on plane to figure out what or how and Im not in a position to take it overhauled professional so time will tell if Im paranoid.

Ian - I was refering to this bit - I thought it was the shift shaft lever or may be Gen 2 is different? visible from the back of the drive when raised with the speedo seal unit
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by BruceK » 07 Sep 2017, 16:13

If the prop has taken a serious knock (and this can be difficult to see on SS props) then in the absence of a shear collet (not sure you have one) you can chip a planetary gear tooth. The swarf if caught in the gears will give a chopper like sound as the gears jump even though the gear still binds.

Image

A shear collet between upper and lower gearboxes that failed to shear caused the damage to the planetary gears

Image
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by Ianfs » 09 Sep 2017, 10:59

Ian - I was refering to this bit - I thought it was the shift shaft lever or may be Gen 2 is different?


I can see what you are getting at. That is the lower shift shaft but its not the shift shaft seal (sometimes known as a shift shaft bushing assembly. Not to be confused with Shift Shaft Bushing which is in the bell housing :D ) . On the Gen 11 as I said it is slightly different to the Alpha One, the seal assembly is below the plate shown although on the Gen 11 it does stick out a little. If you were able to see inside where the seal is then great, but I'm not sure you would see a weep clearly. Mind you having said all this I do remember when working on a mates Gen 11 last year, it was clear that oil was seeping from the drain hole, if yours isn't then clearly its not this. See arrow for the Shift Shaft Seal Assembly............

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by betty boop » 11 Sep 2017, 09:13

BruceK wrote:If the prop has taken a serious knock (and this can be difficult to see on SS props) then in the absence of a shear collet (not sure you have one) you can chip a planetary gear tooth. The swarf if caught in the gears will give a chopper like sound as the gears jump even though the gear still binds.

Image

A shear collet between upper and lower gearboxes that failed to shear caused the damage to the planetary gears

Image


is that likely to cause a noise thats intermittent ? and how would you tell the tooth has gone without a full strip down ?
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