Morse cables

[davidk65]

To control engine revs and gearbox selection I have a single lever control with 2 cables connected, 1 cable to the gearbox and the other to the engine.

With the control in nuetral I can pull the control lever outwards which allows me run the engine without engaging forward or reverse, in this position the engine performs "as sweet as a nut" no roughness or vibration even at tickover. However, with fwd direction engaged (and sometimes rev) and the need to slow and stop arises, putting the control in neutral (tick over) the engine runs roughly with increased vibration. A quick flick of the controls into fwd or rev and then back to neutral often clears this situation. I assume that this is because the cables need adjusting, but the question is which one, or is there possibly another cause?

On the subject of cable adjustment, does gear selection proceed increased engine revs or does increased engine revs take place before gear selection?

The engine space on our 32 footer is small and with an increase in my age and weight, I find it very difficult to reach the clevis pin on the selector on the gear box and I can't even see the fuel pump connection so the prospect of making lots small adjustments to the controls is a bit off putting. I feel I need to get the theory of it right before making a start (if this is the problem).

 

Advice and comments please.

[John Orentas]

Hi David.

 

The control system should always be set up in such a way that a gear is fully selected (and with a bit of over-run) before the extra power is applied and should clearly go out of gear when told to do so.

 

Can you see that the prop shaft is still rotating when it should be stopped, or is it rotating at reduced speed, if this is the case it needs urgent attention. The lever on the gearbox should be seen to click distinctly into place when neutral is selected.

 

But start with the more obvious things first before looking for adjustments. When did you last go down your weed-hatch to check for prop fouling, it could be as simple as that. Run your hand around the propeller does it feel ok, no lumps missing or things bent? How is the drive transmission, any sign of things out of alignment or suffering from excessive wear or lack of lubrication.

 

I think you should elaborate a little on what you call 'roughness', given that there are a lot more bits and pieces spinning round when in gear you would expect a distinct change when coming out of neutral.

 

A boat engine that ticks over comfortably in neutral should turn the prop at that equivalent speed without problems, don't adjust the slow running until you have run out of other options.

[Sir Nibble]

My 1.8 BMC always ran as rough as a bears arse in gear at tickover, approaching a lock or mooring would have the engine doing its best to abandon ship. The cause was a loose engine mount, now much happier.

[davidk65]

Hi David.

 

The control system should always be set up in such a way that a gear is fully selected (and with a bit of over-run) before the extra power is applied and should clearly go out of gear when told to do so.

 

Can you see that the prop shaft is still rotating when it should be stopped, or is it rotating at reduced speed, if this is the case it needs urgent attention. The lever on the gearbox should be seen to click distinctly into place when neutral is selected.

 

But start with the more obvious things first before looking for adjustments. When did you last go down your weed-hatch to check for prop fouling, it could be as simple as that. Run your hand around the propeller does it feel ok, no lumps missing or things bent? How is the drive transmission, any sign of things out of alignment or suffering from excessive wear or lack of lubrication.

 

I think you should elaborate a little on what you call 'roughness', given that there are a lot more bits and pieces spinning round when in gear you would expect a distinct change when coming out of neutral.

 

A boat engine that ticks over comfortably in neutral should turn the prop at that equivalent speed without problems, don't adjust the slow running until you have run out of other options.

[davidk65]

Hi.

 

Thanks for the comments.

The weed hatch is clear, checked just a few days ago after entering our home marina.

 

"Is the prop shaft still turning when in neutral".

That's a very good question; I honestly don't know. I will check this on my next trip out, the problem is that it does not always occur but when it does it's at the most inconveinient moment when I can't get to lift up the hatch.

 

I have run in gear whilst moored and the alignment seem to be ok, nothing seems to be out-of -line, but I have have not checked the engine mounts yet.

 

I have never had the controler out of it's mounting, but do morse cables have adjustments at either end to save disapearing down the "dark hole"

 

David

[davidk65]

Hi David.

 

The control system should always be set up in such a way that a gear is fully selected (and with a bit of over-run) before the extra power is applied and should clearly go out of gear when told to do so.

 

Can you see that the prop shaft is still rotating when it should be stopped, or is it rotating at reduced speed, if this is the case it needs urgent attention. The lever on the gearbox should be seen to click distinctly into place when neutral is selected.

 

But start with the more obvious things first before looking for adjustments. When did you last go down your weed-hatch to check for prop fouling, it could be as simple as that. Run your hand around the propeller does it feel ok, no lumps missing or things bent? How is the drive transmission, any sign of things out of alignment or suffering from excessive wear or lack of lubrication.

 

I think you should elaborate a little on what you call 'roughness', given that there are a lot more bits and pieces spinning round when in gear you would expect a distinct change when coming out of neutral.

 

A boat engine that ticks over comfortably in neutral should turn the prop at that equivalent speed without problems, don't adjust the slow running until you have run out of other options.

 

Hi John.

Had a run out on the boat and checked some details.

1: When the roughness occurs, in neutral, the prop shaft does not turn.

2: Roughness: the engine rocks from side to side, the movement evens out when the rev's are

increased e.g. at 1000 or slightly above everything is OK. Below 1000 and the roughness appears. I get the impression that at some point fwd or rev is still engaged and there are insufficient engine rev's.

Question: Because I can run my engine without engaging gear, is it a good idea to set the engine tickover this way 1st and then adjust the gear cable?

 

David.

Edited August 11, 2006 by davidk65

[John Orentas]

Hi John.

Had a run out on the boat and checked some details.

1: When the roughness occurs, in neutral, the prop shaft does not turn.

2: Roughness: the engine rocks from side to side, the movement evens out when the rev's are

increased e.g. at 1000 or slightly above everything is OK. Below 1000 and the roughness appears. I get the impression that at some point fwd or rev is still engaged and there are insufficient engine rev's.

Question: Because I can run my engine without engaging gear, is it a good idea to set the engine tickover this way 1st and then adjust the gear cable?

 

David.

 

 

Hi David.

 

I still suspect you have a bit of trouble with gear selection, even though the shaft is not turning it may still be trying to engage a gear and putting a load on the engine, just to repeat when neutral is selected the lever on the gearbox should decisively clunk into position and you should have the same effect when going into either gear.

 

Have another look at that lot, then OK speed up the engine tick-over speed but don't do it by adjusting the cables. You don't say what engine you have but you will find a 'Stop screw' on the injector pump. With the engine warmed up adjust the stop until you have a smooth tick-over, but don't over do it or you will start to experience other problems.

 

If you can't get in there too well get someone to do it for you, I have the same increasing problem as the years go by.

 

But keep an eye on that gear selection.

Edited August 11, 2006 by John Orentas