Dodgy cutless bearing?

VADROUILLE

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Just moored up in brighton and when i was just putting the engine into gear in low revs a very large knocking sound was to be heard. An alarming one to say the least. Increase the revs and the knock goes away, (i motored in at 2500rpm for 6 miles with no noise or any reason to be alarmed).

I put the gearbox in gear manually and i can confirm that the knock is coming from the cutless bearing area.

The engine does vibrate a bit and you can see that in tick over (not in gear) that the shaft is vibrating. i have installed new bigger engine mounts to the engine so i dont think i can do much more with the little bit of vibration thats left.

I also have just been lifted into the water after a week of being out. it should be noted that this knocking sound was never present before i got lifted out and whilst i was out i done two things.

1, i painted all the stern gear (shaft, prop, bracket etc etc) with stern gear antifouling. never done it before, never really needed to. But just thought i would do it for a change. would the extra weight of the paint or something stupid like that cause this knock?

2, i fitted a rope cutter, the type that bolts directly onto the shaft like a clamp, think its called prop protector or something, they advertise in ym. I think it could be that, however i followed all the instructions when i fitted it.

would either of those two things make this knocking noise?

could the engine be misaligned?

I did check the cutless bearing, all the little channels were there for the water flow and it did not look to be worn in anyway.

it should also be noted that i still get the occasional problem with going into gear, sometime it wont go, however when i do it locally it goes in gear fine which leaves me to believe its the morse controls, cant be the cables as they are new.

If anybody can shed some light onto this matter i would appreciate it!
 

theoldsalt

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You seem uncertain if a shaft anode is fitted but have never replaced one.

The reason I ask is that old ones can come loose due to erosion. the wash from the prop can cause a loose shaft anode to slide along the shaft and hit either the P bracket or the hull. This creates a knocking noise as the shaft rotates. I have had this problem - frightened me - so no longer fit a shaft anode.
 

VADROUILLE

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well i did not see one when i painted the shaft, everything is bonded well to my main anode so i have no reason to fit a shaft anode. there may have been one fitted in the past but i dont know as i have only had the boat 2 years.

its a noise i dont like anyway!
 

Tranona

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Does it happen in both forward and reverse? How much clearance was there between your cutting disc and the P bracket? Engines can move up to 6mm when you go into gear and it could be the disc hitting the P bracket. Once it is in gear the engine tends to move back as the mounts settle.

Vibration at tickover might suggest loose mounts or mis alignment. Difficulty getting into gear can be checked by seeing if the lever is fully home when the control is operated.
 

VADROUILLE

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Does it happen in both forward and reverse? How much clearance was there between your cutting disc and the P bracket? Engines can move up to 6mm when you go into gear and it could be the disc hitting the P bracket. Once it is in gear the engine tends to move back as the mounts settle.

Vibration at tickover might suggest loose mounts or mis alignment. Difficulty getting into gear can be checked by seeing if the lever is fully home when the control is operated.

I think i might have an issue with alignment.

the cutter i fitted said to have a gap of 8mm i think, but i had loads of room so its got a very big distance at least 20mm between the cutter and the bracket.

the gear issue is easy, she does not allways make it home when i use the actual controls. if i disconect and do it by the gearbox itself then she allways makes it home. so would a good asumption be that if the engine is not correctly aligned then it could cause this knocking (allthough, dont forget i have only just started getting this knocking, but then this is the first time the engine has been run with new mounts with any substantial distance)

and it could also be the cause of this gear issue, i would assume that if the engine is vibrating in low revs when im trying to put it in gear then the vibration could be the cause of the gears not making it all the way home?

and if we think this is the cause then is there a simple way i can check the alignment, without a call out charge? the engine has been run from london to portsmouth and now from there to brighton, no substantial issues except this knocking that just appeared as i entered brighton and the gear issue since i left london, allthough that is alot better than what it was, but still not 100%.

I have a deep sea seal if that helps, and it does not leak
 

Tranona

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Alignment is easy to check, although not always so easy to correct. Undo the coupling and measure the gap beytween the faces. It should be equal all round. If you have just fitted new mounts then the alignment should have been checked afterwards. Gear not going home fully is probably poor adjustment of the cable. Correct it quickly or you will wear the clutch in the gearbox.
 
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