Loud whining noise and engine labours - 1gm10 new PSS seal

[snoozydude]

Howdy

I recently replaced my old PSS seal with a new one. It appears to be working fine however I have experienced a strange problem that I am not sure is related.
Occasionally after about 5mins of motoring there is a loud whining noise and the engine labors and will stop unless I take it out of gear.

When I take the elevator downstairs and check the PSS seal by burping it there seems to be good water flow getting through. I cannot feel any heat that might be associated with friction.

I was even suspecting that the graphite surface was sticking when it was wearing in but it should be well polished by now (about 20 hours running on the new seal).

Once this whining noise starts it will occcur shortly after putting the engine in forward in forward but not reverse. This will go on for about 30 minutes as I check all possible options then completly stop and away I go without an issue.

Had a thought it might be the alternator belt was too tight as that is exactly the sort of noise that is made but I would expect I would smell someting if there was that much friction on the belt. Have not had a chance to check the belt option but cannot think of any other options.

Gearbox oil is good and full and when I stop the engine and turn the shaft by hand I cannot feel any significant resistance.

Any help would be most appreciated.

 

[macd]

Presumaby you removed the gearbox coupling and pushed the prop shaft back to fit the new PSS? Is it remotely possibly that in reassembling it the fitted length is different? This could account for binding in forward but not reverse (perhaps through a shaft anode, ropecutter or even the prop boss touching a fixed part).

 

[RichardS]

Too loose an alternator belt will tend to squeal when the engine starts and the battery is demanding a higher charging current but will usually settle down after a short time. Stop the engine whilst it is squealing and feel the belt. If it is warm the belt is too loose.

Too tight a belt would be very unusual as it is not that easy to overtighten and it tends to stretch and loosen off fairly quickly in any event. A very tight belt might give rise to bearing squeal but if the belt didn't stretch I would expect the squeal to continue until it changes to a rattling sound as the bearings throw in the towel. However, that is speculation as it is an unlikely scenario in the first place.

Richard

 

[superheat6k]

My new PSS squealed slightly for a few months after install at idle, but with 255 HP available the engine did not protest unduly at any resistance to motion. For a small engine I would be concerned the seal is not binding.

Have you set the correct loading for the rotor against the stator = for smaller seals this is ~19mm, larger 25mm ?

PSS install instructions available here www.pyiinc.com

 

[earlybird]

I can't imagine that the problem lies with the seal. For a PSS seal to stall an engine even as small as a 1GM10, the torque on the rubber bellows would cause a disastrous failure of that component, I would expect. Also, the problem occurs in forward gear, ie when prop. thrust is unloading the seal faces. I'd look elsewhere for the cause.

 

[TQA]

Is it possible for the front face of the prop to be touching the shaft bearing? If yes that might explain things.

When ei heats up the shaft it lengthens slightly.

 

[GrahamM376]

If a Spurs or Stripper is fitted, has it been refitted too far forward without allowing clearance in the "V" block for the shaft to move forward under load?

 

[Mistroma]

A squealing sound could be the alternator belt. However, that doesn't fit with your other symptoms and I'd rule it out. Even if the alternator bearings seized it wouldn't explain the difference between forward and reverse.

I doubt that friction in PSS seal would explain it either as it's unlikely to generate enough friction to stall the engine without damaging the seal. You also say that the seal is not warm and does have water. So I'd tend to rule that out as well.

I'd agree with macd, TQA and GrahamM376. You will have uncoupled the shaft from the gearbox in order to fit the seal and so it is likely that it was not refitted in exactly the same position. Forward thrust from the prop. could now be pushing the prop or something else fixed to the shaft (cutter or anode) far enough forward to bind. It also explains why reverse is OK.

 

[macd]

Quite so, Mistroma.
Rule 1: if you've had something apart that develops a fault after it's put back together, you've probably put it together wrongly.
Rule 2 is generally the same.

 

[EdWingfield]

Alternator drive belt is the easiest and cheapest fix ie. zero dollars. Tighten it, run the engine. No change? Put the adjustment back as before (you'll see the marks)

Only when you've ruled that out do you move on to the expensive stuff.

 

[ghostlymoron]

In my experience, its never the cheap things that go wrong :-(

 

[GrahamM376]

Alternator drive belt is the easiest and cheapest fix ie. zero dollars. Tighten it, run the engine. No change? Put the adjustment back as before (you'll see the marks)

Only when you've ruled that out do you move on to the expensive stuff.

OP's comments suggest something in the drive chain.

"Occasionally after about 5mins of motoring there is a loud whining noise and the engine labors and will stop unless I take it out of gear".

 

[macd]

Alternator drive belt is the easiest and cheapest fix ie. zero dollars. Tighten it, run the engine. No change? Put the adjustment back as before (you'll see the marks)

Only when you've ruled that out do you move on to the expensive stuff.

If the alternator belt is actually making the engine labour, as the OP describes, it's so tight the bearings are probably now knackered, so not as cheap as you suggest. Money on it not being that.
If the shaft has been inadvertently fitted too 'short', that's a pretty cheap fix, too -- as in $0. It also has the benefit of explaining all the symptoms.

 

[snoozydude]

Thanks

>I'd agree with macd, TQA and GrahamM376. You will have uncoupled the shaft from the gearbox in order to fit the seal and so it is likely that it was not refitted in exactly the same position. Forward thrust from the prop. could now be pushing the prop or something else fixed to the shaft (cutter or anode) far enough forward to bind. It also explains why reverse is OK.

Thanks - I will have a look at this as the coupling collar that joins the shaft to the gearbox was one of the things that could vary the length of the shaft assambly and I managed to rub off my mark in the wrestle to get it off.

I know there is 25mm between the prop face and the bearing. I have a mark on inner hull aligning with the pss rotor to gauge the forward movement on the shaft and I can see rotor it is not pushing forward 25mm to be able to rub on the bearing.

There would have to be some movement and I will try and gauge it better - maybe take a photo or movie so I can slow it down and examine in in detail.

I would expect the difference in length after reassembly is going to me minimal which probably explains why the problem seems to go away. Hopefully not because some significant wear or damage has been done.

I do not really understand the term "binding" but it was a suspicion I had that there was some issue with the clutch.

 

[Mistroma]

Bind has several meanings but in this context it just means "to stick or become stuck".

e.g. You could have said binding instead of sticking regarding the seal. >>>"I was even suspecting that the graphite surface was sticking".

I hope that adjusting the coupling does solve the problem.

 

[JumbleDuck]

When I got my 1GM10 it would occasionally make nasty noises and bearing work in gear. Rather later than I should I have I worked out that an alternator bearing was tightening when hot, overloading the drive belt (hence the squealing) and slowing the engine.