Smell of burning rubber?

[Carmel2]

Hi,

The last two times I went hard astern I could smell burning rubber, not much and it went when I slowed it down. I have had a look at the rubber stuffing box and does not need any lubrication. I haven't had the chance to get a look at the cutlass bearing, these being the only rubber parts that get any friction. It's a new shaft, propeller, cutlass bearing and stuffing box, so it could just be bedding in, any other thoughts out there?

 

[ribrage]

Hi,

The last two times I went hard astern I could smell burning rubber, not much and it went when I slowed it down. I have had a look at the rubber stuffing box and does not need any lubrication. I haven't had the chance to get a look at the cutlass bearing, these being the only rubber parts that get any friction. It's a new shaft, propeller, cutlass bearing and stuffing box, so it could just be bedding in, any other thoughts out there?

Alternator belt ?

 

[Carmel2]

Alternator belt ?

Just had a look and the teeth are fine and the tension is set right, good thought mind...

 

[ribrage]

Just had a look and the teeth are fine and the tension is set right, good thought mind...

Any black dust ? ...only good thought ive had all day

 

[Carmel2]

Any black dust ? ...only good thought ive had all day

A small amount yes.......

 

[Chris_Robb]

Hi,

The last two times I went hard astern I could smell burning rubber, not much and it went when I slowed it down. I have had a look at the rubber stuffing box and does not need any lubrication. I haven't had the chance to get a look at the cutlass bearing, these being the only rubber parts that get any friction. It's a new shaft, propeller, cutlass bearing and stuffing box, so it could just be bedding in, any other thoughts out there?

I take it that the exhaust hose is properly watered - going ahead you leave the smell behind...... unlikely as it would have melted by now!

 

[vyv_cox]

There are not very many rubber parts and several of those are water cooled/lubricated, so very unlikely to overheat. Drive belt seems the most likely, cutless bearing, shaft seal and exhaust hose would surely have made themselves evident by now if not being cooled. Is there a flexible gearbox coupling that might be rubbing on something when going astern?

 

[Tony Cross]

Shaft seal?

 

[vyv_cox]

Shaft seal?

Volvo ones are renowned for squealing when they run dry of grease and/or water, so I don't think so.

 

[Carmel2]

I was going down the drive belt route, but as we backed in a few hours ago the OH had good old sniff around and nothing in that area, oil level is fine.........

 

[Carmel2]

Well I am told it's soot from not driving the engine hard enough.

 

[LadyInBed]

Hi,

The last two times I went hard astern I could smell burning rubber, not much and it went when I slowed it down.

If it doesn't happen when you go 'hard forward' then that rules out belt slippage.

It's a new shaft, propeller, cutlass bearing and stuffing box, so it could just be bedding in

It suggests to me that the gap between the propeller and the cutlass bearing is either too small, you are getting cavitation or the gap is obstructed so water can't lubricate the cutlass bearing when going hard astern.
You must have a good nose to be able to smell it

 

[Steve C Cronin]

The "new" low sulphur diesel smells like that and it is just your exhaust overtaking you. In the Ionian, where we often have to motor into static wind it is quite common.

 

[Carmel2]

The "new" low sulphur diesel smells like that and it is just your exhaust overtaking you. In the Ionian, where we often have to motor into static wind it is quite common.

Thank you for that.

 

[Bilgediver]

Hi,

The last two times I went hard astern I could smell burning rubber, not much and it went when I slowed it down. I have had a look at the rubber stuffing box and does not need any lubrication. I haven't had the chance to get a look at the cutlass bearing, these being the only rubber parts that get any friction. It's a new shaft, propeller, cutlass bearing and stuffing box, so it could just be bedding in, any other thoughts out there?

Is it possible that the Hard Astern is causing aeration of the water under the boat and this is causing the sea water pump to lose suction. The engine will take a while to overheat as it is circulating fresh water. However the exhaust would be instantly short of water and start to get hot.

Forget about cutless bearings as they are went and below the water so only the Sea horses might smell them