Isolated Earth or not on PErkins 4236 1979

[Birchwood33]

Hi all,
I'm trying to figure our if my Birchwood 33 Perkins 4.236 1979 engine has isolated earth or not. The senders for gauges are different if it has isolated earth.
I'm guessing I could see if the engine block and negative wires have continuity?
But does any one with similar engine and year know?
Also does anyone know how much roughly a Birchwood with one 4.236 engine weighs? Rough estimate like between 6 and 7 ton?
I have searched the manuals/internet inside and out and can't find any answers.
Be grateful to find out.
Regards,
Michael

 

[VicS]

Hi all,
I'm trying to figure our if my Birchwood 33 Perkins 4.236 1979 engine has isolated earth or not. The senders for gauges are different if it has isolated earth.
I'm guessing I could see if the engine block and negative wires have continuity?
But does any one with similar engine and year know?
Also does anyone know how much roughly a Birchwood with one 4.236 engine weighs? Rough estimate like between 6 and 7 ton?
I have searched the manuals/internet inside and out and can't find any answers.
Be grateful to find out.
Regards,
Michael

Yes check for continuity between the battery negative and the engine block
You should be able to see where the battery negative cable goes. If it goes to the engine block you dont have an isolated system

Also look at the existing gauge sensors . If they have a single connection you don't have an isolated system. If they have two connections you probably do have a isolated system

 

[FlyingGoose]

I cannot help you with the testing , but as VIc says the negative will go to your engine block, my 4236 Perkins engine has this set up and I can clearly see the negative attached to the block
As for weight no idea , I can give you my boat weight of 12 tonnes at 42 ft also built in 1979 do not know if that helps

 

[B58]

Hi all,
I'm trying to figure our if my Birchwood 33 Perkins 4.236 1979 engine has isolated earth or not. The senders for gauges are different if it has isolated earth.
I'm guessing I could see if the engine block and negative wires have continuity?
But does any one with similar engine and year know?
Also does anyone know how much roughly a Birchwood with one 4.236 engine weighs? Rough estimate like between 6 and 7 ton?
I have searched the manuals/internet inside and out and can't find any answers.
Be grateful to find out.
Regards,
Michael

Look at the senders and switches if they have two connections (see pic)

 

[Bav32]

I'm involved in maintaining a boat with a 4236.
I only realised the full implications on the non earthed engine when dealing with a intermittent charging problem that turned out to be an intermittent high resistance "earth" to the alternator. Not helped if you get stay earths on things like throttle or gear change cables etc.
As others have said, the easiest way to check is probably to look at the temperature and oil pressure sensors that will be two wire if the engine body is isolated.
If you need a replacement alternator, car types that use the chassis for the -ve return may not work on an isolated engine.

On the isolated engine, the +ve and -ve battery cables go to terminals on the big starter motor, where smaller +ve and - ve terminals for distribution appear.
Suspect the differences are because the engines have multiple uses. In particular, must be a nightmare for steel hulled boats,trying NOT to get the battery -ve in contact with the hull causing anodes to last only weeks.

 

[Birchwood33]

Look at the senders and switches if they have two connections (see pic)

Ya they all have two connections. Maybe it is isolated earth. Will check out when I get to it. Thanks very much.