Does diesel eat rubber?

[vyv_cox]

I suppose it's worth ensuring that an engine mount below a fuel filter/seperator is well covered up and washed off with detergent if splashed though. An experienced marine mechanic gave my engine a good checking over recently and apparently diesel drips can accelerate a mounts disintegration in his experience/opinion.
John Cutler... http://www.cutlermarine.com/

Very much so. Engine mountings may be made of a wide variety of elastomers, including natural rubber. This has very poor resistance to hydrocarbons and diesel will soften it severely. I have seen diesel-soaked engine mounts that could be wiped off with a finger!

I have posted this before but everything you need to know about the resistance of elastomers to liquids can be found at http://www.quickcutgasket.com/chemicalresistance.html

 

[DaveS]

I'm told by a reliable engineer that diesel can/does attack the rubber used in raw water cooling impellers. That can come about when running the engine in a diesel-contaminated marina/harbour.

"Far-fetched," I thought at the time. Not any more.... It may take a while, but a film of diesel on one's impeller can destroy the integrity of the core which binds the rubber blades to the rotating shaft.

I take the point, and have experienced an impeller that became detached from its metal ring. However, unless conditions are exceptionally violent I cannot see how a surface film of diesel can get picked up by the water intake some inches below (over two feet in my case - sail drive) the surface. Am I missing something?

 

[bluedragon]

Agreed. How is a film of diesel on the surface going to get into the intake...unless as I've seen the marina dory racing around in circles trying to disperse it! But, a "film" on the impeller is not likely to do much harm IMO. It would have to sit in diesel contaminated water for some time for there to be enough present to swell the rubber I'd have thought.

 

[alant]

Cling film?

Been messing around with the fuel pipes on my boat over the last few days. The pipes are armoured and where the jubilee clips are placed, what I assume to be self-amalg tape has been wrapped round- possibly the jubilee clips are a bit on the big side and this helps them to pack them out.
Anyway, the rubber tape has turned into a sticky gooey mess, and might be the source of some problems I've had with air in the fuel. It seems like maybe the tape is breaking down. I know that you have to keep some rubber compounds away from diesel. Any suggestions for something more robust that I can put on in place of the gunky self-amalg tape?

I've got a rubber priming bulb on my diesel & started having problems with the engine firing when cold start-up (fuel 'shortage'), traced to air getting into the bulb & allowing fuel to run back down to tank when idle.

As a 'temporary' measure, until I can renew this bulb (a common problem on these engines), clingfilm was suggested & has continued to stop air getting in (& I assume any fuel getting out), for the last month. Engine fires almost instantly on turn over when glow plug light goes out. (also when last calculated, doing 62mpg )

 

[Kelpie]

Thanks for the tip, I shall try that. It also crossed my mind that I have some PTFE tape aboard- might this be suitable?

 

[Kelpie]

Just a cheeky bump of this thread to re-ask:

Could I use PTFE in place of the SAT? Is it compatible with diesel?

 

[prv]

Could I use PTFE in place of the SAT? Is it compatible with diesel?

If you're going to the effort of fixing it, why not do it properly with the correct sized hose clamp?

Pete

 

[Deleted member 36384]

Just a cheeky bump of this thread to re-ask:

Could I use PTFE in place of the SAT? Is it compatible with diesel?

The PTFE tape has low friction properties. It is likely not to provide a good grip if compressed between the hose clip and the hose, the grip will be further compromised as the diesel will eliminate any amalgamating properties of the PTFE, allowing the tape to tape interface to slip about. Fuel hose and hose clips are low cost items, so you should buy the correct size and fit.

 

[Kelpie]

OK, so PTFE not the best solution. I have armed myself with the smallest stainless jubilee clips I could find in Inverness. The boat has to cross the Minch tomorrow so I don't have time to do a proper repair.

 

[rob2]

When I bought my boat in West Mersea, the engine was recommisioned/dewinterised by the local marine engineer ready for the delivery trip to the Solent. It ran for abut twenty minutes! When we had successfully completed the crossing of the Thames Estuary and entered Ramsgate without power, one of the crew discovered that the clamped ends of the fuel hoses had softened, allowing the engine to suck in air. With the ends cut off and the hoses reclamped, we had no further problems.

The moral of the story is that it is worth replacing old hoses with new, well fitting ones!

Rob.

 

[SHUG]

To change tack....I see that my local garage has diesel "with 7% biodiesel". I have read that biodiesel is particularly harmful to "rubber".

 

[Kelpie]

When I bought my boat in West Mersea, the engine was recommisioned/dewinterised by the local marine engineer ready for the delivery trip to the Solent. It ran for abut twenty minutes! When we had successfully completed the crossing of the Thames Estuary and entered Ramsgate without power, one of the crew discovered that the clamped ends of the fuel hoses had softened, allowing the engine to suck in air. With the ends cut off and the hoses reclamped, we had no further problems.

The moral of the story is that it is worth replacing old hoses with new, well fitting ones!

Rob.

Glad you were able to complete the trip safely!
Having tidied up the mess left by the old SAT, and fitted the new clips as tight as possible, I have had no further problems with air in the pipes. The pipes are all very new and are armoured- maybe the SAT was put there to help keep the jubilee clips in place on the steel armouring?

Oh, one more question- how the heck are you supposed to cut armoured fuel pipe? I thought one end that I'd been messing around with and was covered in gunky rubber tape looked so bad I'd just cut it off with a hacksaw. But what I was left with wasn't much better as the braided armouring just wanted to unravel itself.