Control Pressure Regulator Fire Risk?

[content22207_2]

Please no flaming -- this is a serious question:

Is the diaphragm inside the CPR made of rubber?

Ethanol can be very hard on rubber diaphragms, causing them to split prematurely. Wreaks havoc on rubber diaphragm fuel pumps when they sit idle.

If the rubber diaphragm inside the CPR is indeed made of rubber, and if it splits, could fuel reach the bimetalic resistance heater? Would that pose a fire risk? Has anybody ever even seen a CPR with a failed diaphragm?

I am seriously wondering if there could be explanations for engine fires other than damaged or leaking fuel lines.

Bill Robertson
#5939

[sdg3205]

I had one apart years ago and it seemed more like a plastic membrane than rubber, but again that was years ago.

[content22207_2]

Chambers in the fuel distributor are separated by a thin metal plate, so they should be OK too.

Ethanol does cause mischief. For example, a tree man recently told me it was causing the plastic fuel lines in his chain saws to split.

Boaters definitely hate ethanol, and the FAA has banned it from aviation fuel.

What seals the accumulator piston?

Bill Robertson
#5939

[David T]

You picked the right word, flaming. IMHO most of the engine fires can probably be traced down to a fuel leak. Either a damaged, kinked, stretched, or otherwise mishandled fuel line, overtightened and broken banjo bolt, resuse of old copper seals, missing seals, or dirt. That CPR has been used in numerous other applications and there doesn't seem to be any indication of a trend of them failing and causing fires.

[content22207_2]

Ethanol's none too kind on fuel pump boots either.

Bill Robertson
#5939

[DMCMW Dave]

To the original question - not likely, and I've never seen it happen. The rubber parts are encased in steel parts internally.

[Bitsyncmaster]

It's a pretty thin disk case so I would assume the internals are metal.

The accumulator probably is a rubber bladder but if it leaks or fails completely, the fuel just flows back to the tank.

I've had to replace fuel lines on all my old yard equipment with Tygon hose.