Is your Volvo Penta saildrive isolated from the engine?

Is your Volvo Penta saildrive isolated from the engine?

  • Yes, there is no electrical connection

    Votes: 15 65.2%

  • No, they are electrically connected

    Votes: 5 21.7%

  • Don't know

    Votes: 3 13.0%
  • Total voters
    23
nigelmercier

nigelmercier

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Yes, they are all isolated from new. So if yours does not appear to be somebody has messed about with it.
 
MD 2020C
MS25S saildrive
2003 Build year

Extract from Owners manual for MD20** series. Page 39
3. The drive/Reverse gear AND flywheel cover are electrically isolated from the engine and must never be used as a ground.
 
duncan99210 said:
Isolated, in accordance with the Volvo Penta installation manual, which tells you that it must be isolated inorder to prevent galvanic corrosion.

MD2030C

120S

2000 (possibly 1999 but fitted in 2000)
Click to expand...

Stork_III said:
MD 2020C
MS25S saildrive
2003 Build year

Extract from Owners manual for MD20** series. Page 39
3. The drive/Reverse gear AND flywheel cover are electrically isolated from the engine and must never be used as a ground.
Click to expand...

Yes and Yes but does it say anything similar in the manual for the MD22 . If so where.. I can't find it

http://vppneuapps.volvo.com/ww/PIE/...403&d=Owners Publication&s=6240500&lang=en-GB
 
My saildrive (120S-D) is very electrically connected to the rear of the engine (MD2040)...

BUT... The part of the engine to which it is bolted is very well isolated from the rest of the engine.

An insulating gasket provides isolation between the engine and flywheel housing as do the bushes and washers under the bolts.

Insulation parts shown as nos. 29, 31 and 32 in this schematic
 
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Hello all,
I'm a new member to the Forum. I have a 1990 F-P "Fidji" cat in Florida, that I have owned for 10 years. My comment? Please, please isolate your drives... Unknown to me, I had one isolated and the other not. The electrolysis ate one sail drive up and had to be replaced, about 8,500 USD. It's an easy fix, but it does take a lot of hours. Please isolate, it's not worth the chance. Cheers, Jim
 
My 29 year old 120SB saildrive gearbox is directly bolted with no gasket to the VP2003 engine, the bolts and washers are stainless steel. Not sure how gaskets and insulated washers could effectively isolate them with all those thru-bolts unless they also had inert sleeves, which I have not heard mentioned. The large external "teardrop" anode is wired to one of those connecting bolts and there is no anode fitted to the engine block on those models. All as per original installation I think. For me the precaution is to have good anodes, and clean connections. There is another anode fitted to the saildrive propeller shaft housing. Both anodes waste which I take as a good sign of their effectiveness.
 
This thread seems to have resurfaced, and is now obsolete. I now know for a fact that my 120S saildrive is not isolated from the engine, and it is not possible to retrofit such isolation.

It is possible however to isolate the entire engine and saildrive from the battery, and this is what many boats use.

Any further replies along the lines of "My saildrive is isolated from my engine, therefore your saildrive should be isolated from your engine" should be treated with derision.
 
nigelmercier said:
This thread seems to have resurfaced, and is now obsolete. I now know for a fact that my 120S saildrive is not isolated from the engine, and it is not possible to retrofit such isolation.

It is possible however to isolate the entire engine and saildrive from the battery, and this is what many boats use.

Any further replies along the lines of "My saildrive is isolated from my engine, therefore your saildrive should be isolated from your engine" should be treated with derision.
Click to expand...

IIRC the lack of isolation in your case was not related to the model of sail drive but was due to the engine ( MD22??) you have
 
Jim - SoBe said:
Hello all,
I'm a new member to the Forum. I have a 1990 F-P "Fidji" cat in Florida, that I have owned for 10 years. My comment? Please, please isolate your drives... Unknown to me, I had one isolated and the other not. The electrolysis ate one sail drive up and had to be replaced, about 8,500 USD. It's an easy fix, but it does take a lot of hours. Please isolate, it's not worth the chance. Cheers, Jim
Click to expand...

Not so straightforward. Like others, I reported (post #9) that my sail drive is not isolated and hasn't been for the last 24 years. Nor is the engine isolated from the battery negative. Nor are there any additional anodes other than the annular one on the sail drive, which typically lasts 2 years - in water slightly colder than Florida's admittedly. (Correction: since last year I've had a supplementary hanging anode over the side made up from all the old half consumed sail drive anodes.) There is virtually no corrosion on the leg. What is not connected to the boat metalwork, however, is the shore power earth... (Cue the "breaking the rules, you'll die" brigade.)

More interestingly, how did you achieve "Super Moderator" status with your first post? :confused:
 
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I have a 2020-B and a 120S. They are supposed to be isolated, and they are not. Several of us all owners of Moody S31's compared notes, none were isiolated despite the manual showing clearly that they should be. One owner reckoned a weak point in the arrangments was a rubber bush at the end of either the stop lever or throttle lever (can't remember which). If the bush wears through, the connection will be completed because the cable outer is clamped to the top of the saildrive unit. His theory, not tested by me. I have a hefty anode connected to the engine block, so (touch wood) no problems so far.
 
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