Volvo Penta leg trim reading wrong, any advice?

[Frontier]

Went to the boat this weekend and while there decided to brush off the props, well the anodes really. I get this brown fluffy stuff collecting on them.

While moving the legs up and down I noticed the Stbd leg would only go down to -1. the Port one goes to -6. Thankfully while SWMBO lowered it with me pushing it with the mop I noticed that it was actually travelling all the way. So in one way that was good news, the leg does go up and down so I would still be able to use it to get on the plane. But that still leaves me with about +4 on the display when its exactly the same depth as the Port leg showing 0.

Tried swapping the connectors between the two displays on the dash and the fault moved, which I guess means its the leg telling the display it is out/up further than it really is by about 4 -5 steps.

I don’t really know where to start, I pulled off the connectors at the drive end and reseated them, but still the same.

Any advice on where to get technical info on how the readout get its info or how to reset it to zero would be very much appreciated.

D

 

[DoubleVision]

Re: Volvo Penta leg trim reading wrong, andy advice?

Your problem here is potentiometer adjustment providing there is no damage to the toothed wheel and rachet on the steering helmet. Check this first as they a vulnerable to damage by barnicles and as they are plastic do harden and become brittle over the years. If these items are ok your potentiometer is set in the steering tube located in the transom shield inside the boat. Not sure which engines you have. With petrol engine the potentiometer is easy to see (2 wires appearing from the steering shaft). With diesels its more difficult as the intercooler pipe spans just the bit you want to get to but easy enough to remove. to adjust the potentiometer you need to slacken the 1/2 bolt securing the fork on the tiller arm that holds the potentiometer in place so that it will rotate. Assign SWMBO to the helm to read the guage as you rotate the potentiometer either way. Once she shouts out -4 tighten the fork nut again and you are sorted. Hope this helps
Paul

 

[mont]

Ditto to follow doublevision advice / method.
Its an easy job but you must have spare friendly & understanding eyes on the dash or it'll drive you mad !!

If you end up with identical readings under load on the water well done, or you can easily tickle with them after first run out. Mine lost -1 after use.

Would add if your fiddling with 'pot' unit dont forget to try and force some nice water friendly 'aqua' grease (£6 per tube) into the steering head grease nipple you can now see on the side of the steering head. Use a grease gun with long rubber flexi hose (about £20 ) for ease. If nipple wont take any grease its probably seized solid and void of grease = fit new nipple 76p. It lubes the steering pin, sleeves / joint and rubber seals to prevent head eventually weeping water down back of transom and eventually seizure, survey defect etc and costly lift out / repairs (£££) . My previous two VP 'full leg services' by technicians clearly didnt include greasing those oh and also the rest of the grease points - but at least the boats got an err 'sevice history' as per the mags. Now do my own service work with a little help from manuals / forum.
Have fun....

 

[DavidJ]

Re: Volvo Penta leg trim reading wrong, andy advice?

[ QUOTE ]
to adjust the potentiometer you need to slacken the 1/2 bolt securing the fork on the tiller arm that holds the potentiometer in place so that it will rotate.

[/ QUOTE ]

Very interesting as I have a similar problem due to barnacle build up on the 'rack' causing a slip against the 'pinion' I have twin KAD43's on 290 legs and unless I've got it wrong the above is not possible.
The fork which hold the potentiometer in place locates in one position only and does not allow the potentiometer to rotate. The only way I see possible to make the readjustment is to undo the screw at the end of the rack and with the leg up half way there is enough slack to rotate the pinion back to where it should be (with of course SHMBO at the helm shouting out figures).
I hope that someone can explain how your suggestion is possible since it would be much easier than my suggestion which would require the boat to be out of the water or snorkling and probably loosing the rack fixing screw.

 

[mont]

Re: Volvo Penta leg trim reading wrong, andy advice?

On my DPA drive, which may be same I think, then feel that providing the gear wheel has been started correctly in the rack, then by slackening / undoing the bolt the 'pot' will then rotate and the reading will then go up and down - you must have a second pair of eyes / helper on the guage to assist.
This mimics the effect of the raising and lowering in reverse effectively for fine tuning the start point reading - its quite sensitive. There is a rod, cog at bottom onto rack which passes up through centre of steering shaft which rotates as you raise and lower.
Once leg is in action then rod spins around and 'pot' counts away reading sending it to the guage. At steering head top the 'pot' is located in it - hidden below is 'joint' which is basically a flat head screw slot and a flat head screw driver affair.
With leg fully down by releasing the 'pot' you can then vary the start reading on the dash.
A bit confusing at first I would agree.

 

[DavidJ]

Re: Volvo Penta leg trim reading wrong, andy advice?

Thanks Mont .....I'm with all that but on mine which is a DPA the fork fits into a distinct location on top of the potentiometer. Yes, you can take the fork off and twiddle the potentiometer to get the required reading but the fork will not rest on the potentiometer properly in that position, in fact it actually touches one of the terminals (which of course sends the whole thing crazy) There is slight movement giving perhaps +/- 1 or 2 adjustment but I'm looking for 3 or 4. I can't believe that my potentiometer is different from everyone elses.
So I'm still stuck with having to loosen the rack and readjust the pinion I think.

 

[mont]

Re: Volvo Penta leg trim reading wrong, andy advice?

As you suggest think your problem may perhaps then stem from the start point, from previous in-correct assembly.
Remove rack and refit as per sequence in manual using split first cog hidden at back of rack as starting point etc.
Let me know if you want exact routine and I will bring VP leg manual back after this weekend.

 

[DavidJ]

Re: Volvo Penta leg trim reading wrong, andy advice?

Thanks Mont I've PM'ed

 

[benjenbav]

I reckon you've swept some of that brown fluffy stuff down the pontoon to me! Although my leg problem is slightly different: Port leg operates normally. Starboard goes to -7 under forward load and +++ under load in reverse. Makes it difficult to park using starboard engine as outer engine to generate turn in reverse but not really a problem to turn round and back in, turning with port as outer engine. I figured it might be a hydraulics leak but would welcome any thoughts.

 

[DavidJ]

Ben, Suggest that you post this as a new topic because I think this one has run out of steam. But, I had the same problem some years back on an earlier petrol Volvo and unless the leg design has changed significantly then it was the latch that needed an overhaul. The latch was designed to hold the leg when going in reverse but also to let the leg come up if you hit an obstruction.
best of luck
David