prop shaft misalligned or gearbox issue? help needed!

[purple8]

hello trusty canalworld peeps!

a few days back I was cruising along and felt I had something on my prop. The normal shuddering tiller told me so. I've just spent 6 months around London so its become a common thing! When I lifted the weedhatch I was surprised to see and feel a clean shaft and prop.

I then followed the shaft back through into the boat and realised some bolts had become a little lose where it is held by the gearbox. So I tightened them.

thinking that would be it, the shuddering tiller had calmed, but still didn't feel 100%... We continued our cruise, into the next lock, put the engine astern and got a crazy engine shudder!?! I have lifted the boards and filmed it occurring for you all to see... It engages into forward fine, then judders pulling it into reverse.

the water in the bilge isn't coming through the stern gland btw its just rain collecting.

I am worried I've done something wrong tightening the bolts? But before I did the prop was actually loose and was easy to move up and down, now its solid. But this new issue has arisen from it.

thank you in advance for ur help!!

VID-20180404-WA0001.mp4

[bizzard]

3 minutes ago, purple8 said:

hello trusty canalworld peeps!

a few days back I was cruising along and felt I had something on my prop. The normal shuddering tiller told me so. I've just spent 6 months around London so its become a common thing! When I lifted the weedhatch I was surprised to see and feel a clean shaft and prop.

I then followed the shaft back through into the boat and realised some bolts had become a little lose where it is held by the gearbox. So I tightened them.

thinking that would be it, the shuddering tiller had calmed, but still didn't feel 100%... We continued our cruise, into the next lock, put the engine astern and got a crazy engine shudder!?! I have lifted the boards and filmed it occurring for you all to see... It engages into forward fine, then judders pulling it into reverse.

the water in the bilge isn't coming through the stern gland btw its just rain collecting.

I am worried I've done something wrong tightening the bolts? But before I did the prop was actually loose and was easy to move up and down, now its solid. But this new issue has arisen from it.

thank you in advance for ur help!!

VID-20180404-WA0001.mp4

If you have flexible adjustabe rubber mountings and you tightened down the top nuts on the gearbox mounts because they came loose ''which is quite common'' it would be the nuts underneath that had  come loose and wound down, which means although it might have dampened some vibration it will have lowered the gearbox and put it out of alighnment with the shaft.

[purple8]

that is kinda along the lines of what I was thinking. Is it easy for a novice to realign the shaft and gearbox? Is it something rcr would do for/with me? As I have cover with them.

also could my engine mounts be part of the issue? As my engine seems to be very jumpy when idling...

[BEngo]

Time to check the shaft to gearbox alignment.  Also look at the engine and gearbox mounts to ensure they are intact and the rubber bits have not gone soggy. If they have you will need to renew them before re-doing the alignment. Then re pack the stern gland.

Don't use it unless essential until you have sorted the alignment or you will soon knacker the stern tube bearing and the tail shaft.

N

[Stilllearning]

I think, from looking closely at purple8’s video that the boat has one of those Vetus stern tubes, so repacking isn’t your usual procedure? I agree about alignment and engine mounts though.

[bizzard]

If it was the mounts top nut that came loose and you tightened them down, try slackening them again, they should have left marks on the stud threads were they were, if so wind them up back to there, and then wind the nuts underneath back up and tighten them. There should be flats on the top of the studs to hold them stilll  with a spanner whilst adjusting these nuts.  At least they will be back where they were. But get the mounts checked and realigned by someone that knows how to do it properly, ''not many of them about'' I'm afraid.

A photo of the actual nuts that you tightened would be useful.

Edited April 4, 2018 by bizzard

[purple8]

indeed... Its a watercooled stern gland, topped up with a pea of grease only every 100hrs or so. It was actually replaced 10 months ago along with the shaft. I feel this issue is stemming from mounts, allignment and probably a lot down to a 2m x 2m tarpaulin getting trapped round the prop and stopping the engine in Brentford, 6 journeys up and down the rubbish filled Hanwell flight picking up much rubbish on every occasion and possibly the amount of stuff in the canals around that area of London. I blame that n e way

 

[bizzard]

4 minutes ago, purple8 said:

indeed... Its a watercooled stern gland, topped up with a pea of grease only every 100hrs or so. It was actually replaced 10 months ago along with the shaft. I feel this issue is stemming from mounts, allignment and probably a lot down to a 2m x 2m tarpaulin getting trapped round the prop and stopping the engine in Brentford, 6 journeys up and down the rubbish filled Hanwell flight picking up much rubbish on every occasion and possibly the amount of stuff in the canals around that area of London. I blame that n e way

 

You should have kept to the Roanoke river, probably much cleaner.

[Slim]

Based on personal experience (BMC 1800, PRM 150, aluminum front mounting brackets, aluminum rear mounting brackets integral with bell housing) you should check out. 1) Is the gearbox still firmly bolted to the bell housing? On mine the bolts worked out of the box allowing the box/housing to separate in reverse. 2) have the front brackets fractured allowing the engine to move? Both of these issues caused my boat to demonstrate identical symptoms to yours. I had also previously had several things around my prop. Should add that the setup had performed perfectly for a number of years.

Frank

 

Have now seen the video and suspect that what I posted does not apply, could still be a broken bracket. 

Edited April 4, 2018 by Slim
now viewed video

[Alan de Enfield]

33 minutes ago, purple8 said:

indeed... Its a watercooled stern gland, topped up with a pea of grease only every 100hrs or so. It was actually replaced 10 months ago along with the shaft. I feel this issue is stemming from mounts, allignment and probably a lot down to a 2m x 2m tarpaulin getting trapped round the prop and stopping the engine in Brentford, 6 journeys up and down the rubbish filled Hanwell flight picking up much rubbish on every occasion and possibly the amount of stuff in the canals around that area of London. I blame that n e way

 

Blame Brexit - everything else is apparently down to it.

[purple8]

diagnosis complete...

I simply decided it was beyond me so called rcr!

verdict is; nothing to do with alignment, or engine mounts, or any loose bolts.... It is actually a failure within the gearbox due to being heavily over filled with atf oil.

the gear box has never been filled by us. We have only removed the dipstick and said "wow, there's plenty in there" and left it. But it seems its been over filled by the previous owner and I have never drained it or even noticed this problem. This has therefore over time damaged the clutch cone used to engage reverse gear. And due to it being MY FAULT... The new one will not be covered by the replacement parts.

time for a swift beer

[Boat&Bikes]

Sounds like Rcr are right. One thing il mention though is did you, or they check, that when selecting reverse that the gear lever travels fully into position? 

[purple8]

yeah. He was checking all levers and bolts and was very thorough with it all tbh. After seeing it happen and seeing the oil levels he said it was the only possibility. And he seemed to know his stuff. He checked all mounts and everything else was fine, no issues, just a bloody over filled gearbox level! Gutted I didn't notice it earlier, have seen the level high, but assumed that was correct... What a muppet

[mrsmelly]

27 minutes ago, purple8 said:

yeah. He was checking all levers and bolts and was very thorough with it all tbh. After seeing it happen and seeing the oil levels he said it was the only possibility. And he seemed to know his stuff. He checked all mounts and everything else was fine, no issues, just a bloody over filled gearbox level! Gutted I didn't notice it earlier, have seen the level high, but assumed that was correct... What a muppet

Its a typical case of B.O.A.T innitt. 

[rusty69]

4 minutes ago, mrsmelly said:

Its a typical case of B.O.A.T innitt. 

Buy Oil At Tesco? Bloody Overfilled A Tad?

Edited April 4, 2018 by rusty69

[mrsmelly]

24 minutes ago, rusty69 said:

Buy Oil At Tesco? Bloody Overfilled A Tad?

Eeeeeeeeeeeeeeeeeeejut

[Boater Sam]

This has struck a chord with me.

Its a Hurth gearbox, right? The reduction ratio in reverse is different from forward. If the engine tick over is too low, it can cause a slight shake in reverse.

I had a boat in for repair that was doing exactly what you describe, slight vibration in forward, bad shake in reverse. Owner was sure it was the gearbox. He had already had someone replace the drive plate without making any improvement.

Wrong!!!! It turned out to be a large piece of polythene caught on the split pin in the prop nut. In forward the prop wash threw it off, but in reverse it grabbed the prop.

I know you say the shaft and prop are clear but check that there is nothing trailing on the end of the shaft around the nut. This guy had missed it when he went down the weed hatch.

Overfilling the  gearbox is very unlikely to damage the clutch cones, I've rebuilt loads of Hurths and never heard of this problem. It is not logical, the Hurth is a simple mechanical box, not Hydraulic, if you filled it to the top with oil it would only leak when it warmed up.

[purple8]

the gearbox us a vetus technodrive. The prop is completely clear end to end. Indeed the gearbox isn't hydraulic. The gearbox I struggling to engage reverse when the throttle is whacked back, but does find it after a few juddering seconds where the prop throws the engine forward and back quite harshly.

was told its ok for now, but it will only get worse with time until eventually there is no reverse gear at all.

tick over is at 8.5 as I believe it should be...

[Boater Sam]

Sorry if I have misled you in any way.

I've never heard of this problem, usually the gear just doesn't engage or slips and lets the engine revs rise.

The Vetus boxes can be a little noisy, they whine. I can only think that there is end float in the shafts that is causing the snatchy take up. I still think that excess ATF oil is unlikely to be the cause.

[purple8]

by excess atf... We are talking only a tad shy of a litre overfilled?! So not slightly but properly overfilled. I've owned the boat for now 15 months and its always been like that. Its ran for 400hrs like it.

so if it is that. I take the blame. Should've been changed by now too tbh! Although some blame should go to whoever put it in in the first place...