The Nov. issue of Sail magaine (p. 61 "Things that Work") has a tip: spray WD-40 into the air intake of a diesel rather than bleading the engine when air has gotten into the line (changing filters, etc.) Has anyone tried this? Seems like and incredibly simple alternative to a very messy job.
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Not According To Yanmar Rep...
..who said he would void a warranty for even just one use of starting fluid or WD 40 for it will break the rings of a high compression (?) diesel such as Yanmar. He said things like that a lot tho... Rick D.
..who said he would void a warranty for even just one use of starting fluid or WD 40 for it will break the rings of a high compression (?) diesel such as Yanmar. He said things like that a lot tho... Rick D.
wd40
ran out of diesel, got towed to pump, bled system for a while, couldn' get it to start and then this old crusty sailor went by and told me just that. throw the 2 levers forward so compression is not at full and then spray wd40 into the air cleaner until it starts , did it 2-3 times it started and it works fine. hunter29.5 (18hp yanmar) 1994
ran out of diesel, got towed to pump, bled system for a while, couldn' get it to start and then this old crusty sailor went by and told me just that. throw the 2 levers forward so compression is not at full and then spray wd40 into the air cleaner until it starts , did it 2-3 times it started and it works fine. hunter29.5 (18hp yanmar) 1994
Considerations
My opinion... It will work, but can cause damage. Not likely with very limited use. I could understand where a manufacturer would void a warranty if they knew you were using such a method to bleed or assist in starting the engine. What really matters is the flash point of the fuel and the rate of burn of the fuel. Gasoline burn rate is rated in terms of "octane", diesel burn rate is rated in terms of "cetane". No. 2 diesel is a mid-distillate with a flash point of about 125 deg. F. WD40 is a light-distillate with flash point of about 110 deg. F. WD40 will flash at a lower temp and burn significantly faster than no. 2 diesel fuel. This places undue stress on all mechanical parts... rings, pistons, rods, bearings, crank, etc. It may seem odd, but the higher the octane/cetane rating, the slower the fuel burns. A slightly slower burning fuel (relatively speaking) will exert a more even and longer lasting force on the piston as the flame front progressing throughout the cylinder as opposed to a fast "explosion" which provider a higher force of shorter duration... in some instances, high enough to cause damage. Thats why certain manufacturers rate their engines for a minimum octane/cetane rating. Higher compression engines (high performance gasoline and all dielsel engines) produce a high amount of heat by compression of the cylinder volume. Engines with higher compression ratios need slightly slower burning fuels to avoid a condition known as "detonation" which can be very damaging - most of us refer to this as "pinging" in our autos. Another condition known as "pre-ignition" results in a similar "pinging" sound and can be be just a big a robber of power and can also cause damage. Fortunately this can only occur in gasoline engines and is much more common in carburated vs. injected gasoline fueled engines. Pre-ignition is where the fuel is prematurely ignited by a hot-spot in the combustion chamber vs. being ignitited "on-time" by the spark plug. On diesel engines, the fuel is not drawn in by the cylinder, but rather injected under high pressure at or near top-dead-center of the piston travel. All that said - be careful about usage of a start assist like this. A simple squeeze bulb or a small electric fuel pump with a remote toggle will help you bleed the system makes for a very easy process. Russ
My opinion... It will work, but can cause damage. Not likely with very limited use. I could understand where a manufacturer would void a warranty if they knew you were using such a method to bleed or assist in starting the engine. What really matters is the flash point of the fuel and the rate of burn of the fuel. Gasoline burn rate is rated in terms of "octane", diesel burn rate is rated in terms of "cetane". No. 2 diesel is a mid-distillate with a flash point of about 125 deg. F. WD40 is a light-distillate with flash point of about 110 deg. F. WD40 will flash at a lower temp and burn significantly faster than no. 2 diesel fuel. This places undue stress on all mechanical parts... rings, pistons, rods, bearings, crank, etc. It may seem odd, but the higher the octane/cetane rating, the slower the fuel burns. A slightly slower burning fuel (relatively speaking) will exert a more even and longer lasting force on the piston as the flame front progressing throughout the cylinder as opposed to a fast "explosion" which provider a higher force of shorter duration... in some instances, high enough to cause damage. Thats why certain manufacturers rate their engines for a minimum octane/cetane rating. Higher compression engines (high performance gasoline and all dielsel engines) produce a high amount of heat by compression of the cylinder volume. Engines with higher compression ratios need slightly slower burning fuels to avoid a condition known as "detonation" which can be very damaging - most of us refer to this as "pinging" in our autos. Another condition known as "pre-ignition" results in a similar "pinging" sound and can be be just a big a robber of power and can also cause damage. Fortunately this can only occur in gasoline engines and is much more common in carburated vs. injected gasoline fueled engines. Pre-ignition is where the fuel is prematurely ignited by a hot-spot in the combustion chamber vs. being ignitited "on-time" by the spark plug. On diesel engines, the fuel is not drawn in by the cylinder, but rather injected under high pressure at or near top-dead-center of the piston travel. All that said - be careful about usage of a start assist like this. A simple squeeze bulb or a small electric fuel pump with a remote toggle will help you bleed the system makes for a very easy process. Russ
Sqeeze pump
To reiterate Russ' poste, based on a tip I got here I put a sqeeze bulb (the kind you get for outboard motors) in the deisel fuel line between the primary filter and the engine. (Others have put the pump in the line between the tank and the primary filter. Bleeding is much easier because the pump is much more efficient at putting fuel into the system.
To reiterate Russ' poste, based on a tip I got here I put a sqeeze bulb (the kind you get for outboard motors) in the deisel fuel line between the primary filter and the engine. (Others have put the pump in the line between the tank and the primary filter. Bleeding is much easier because the pump is much more efficient at putting fuel into the system.
bulb and wd
I have added a bulb between tank and primary filter, I found this a must, the yanmar pump is nice but the bulb is significantly easier especially when harried. I have also used wd 40, it works great, Nygel Calder mentions this in his Mechnaical Book (buy it). When you have bled everything and there is still some air trapped somewhere, probably the injector itself, wd40 works great. Never ever use starting fluid. its flash point is tooooo low and will ignite before the piston is ready and give the yanmar a real bad day. Change filters and bleed and tighten everything regularly on a calm day in the slip and the world will be a better place.
I have added a bulb between tank and primary filter, I found this a must, the yanmar pump is nice but the bulb is significantly easier especially when harried. I have also used wd 40, it works great, Nygel Calder mentions this in his Mechnaical Book (buy it). When you have bled everything and there is still some air trapped somewhere, probably the injector itself, wd40 works great. Never ever use starting fluid. its flash point is tooooo low and will ignite before the piston is ready and give the yanmar a real bad day. Change filters and bleed and tighten everything regularly on a calm day in the slip and the world will be a better place.
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