Can you use CRC Brakleen as starting fluid for a marine engine?
I have a stubborn old diesel engine on my cruiser that struggles to fire on cold mornings. I usually use a quick squirt of Easy Start but I've completely run out. I do have a tin of CRC Brakleen in my toolbox. Can you use Brakleen CRC as starting fluid just to get it going?
Answer
You should never use CRC Brakleen or any other brake cleaner as a starting fluid in a marine engine. Depending on the exact chemical formula in the tin, it will either produce deadly toxic gas when heated or completely strip the vital lubricating oil from your cylinder walls.
Toxic Chlorinated Brake Cleaner
CRC produces several formulas of Brakleen. The traditional red tin contains tetrachloroethylene. This chlorinated solvent resists fire and will not help ignite your fuel mixture. If you spray it into a running intake, the extreme heat of combustion alters the chemical structure of the solvent.
When exposed to high heat or an open flame, chlorinated brake cleaner breaks down into phosgene gas and hydrogen chloride. Phosgene is a highly toxic chemical weapon used in the First World War. Inhaling even a small amount in the confined space of a boat engine bay can cause severe respiratory failure or death. Never allow chlorinated solvents near a hot engine block, exhaust manifold or intake.
Non-Chlorinated Cylinder Scoring
The green tin of non-chlorinated CRC Brakleen contains a blend of highly flammable solvents like heptane, acetone and toluene. These volatile chemicals readily ignite in a cylinder and might make a dead engine kick over. Doing so causes catastrophic internal wear.
Brake cleaner is an aggressive degreaser designed to strip away oil and grease. When drawn into the air intake, it washes the ultra-thin layer of lubricating engine oil straight off the cylinder walls. As the piston rings travel up and down the dry steel or cast iron bore, you get immediate metal-on-metal friction. A few seconds of cranking a dry cylinder will score the liners and rapidly accelerate piston ring wear. This ruins the engine compression. Dedicated starting fluids, such as Holts Bradex Easy Start (around £6 a tin), use ether for ignition but contain a small amount of upper cylinder lubricant to protect the metal surfaces.
Pre-Ignition in Marine Diesels
Even with proper starting fluid, you must exercise extreme caution when spraying aerosols into marine diesels like a Volvo Penta MD series or a Yanmar YM. Diesels rely on high compression ratios (often between 18:1 and 22:1) to generate enough heat to ignite heavy fuel. Volatile solvents like acetone or ether ignite much earlier in the compression stroke than diesel fuel does.