yanmar diesel not starting?

There are only two things that will keep any diesel engine from starting; no fuel to the injectors, or no spark. Since there are no spark plugs, the answer is pretty straightforward.

You need to systematically work through the fuel system to get all of the air out of the lines. Make sure that the replacement filter is full of clean fuel before you install it. Crack the fuel line at the highest possible point and crank the engine until fuel comes out, then tighten up the line and try to start it.

On the north slope of Alaska, I have put a propane torch to the exhaust manifold to create a hot spot to aid start up. Just be careful to keep the heat on the exhaust iron and away from the fuel line. This probably isn't necessary as I would bet my big wrench that you that you have air in the line where fuel should be. Good luck.

Seismoa
January 2009

Well, there's a few things to check that should eliminate the obvious problems. First, loosen a fuel line at one of the fuel injectors and crank the engine. You should be getting fuel as the engine cranks, if not you have a blockage, a vapor lock, or a bad pump somewhere. When you replaced your fuel filter, I hope you purged air from the lines or at least filled the filter with clean diesel before putting it in. Fuel pumps can't pump air.

If you have glow plugs on your engine you need to check those to make sure they are getting hot. If you have a voltmeter make sure that there is power to the glow plug during the start cycle. Also check resistance between ground and the lead of the glow plug - if it is open (infinite resistance) your glow plug is bad.

Still won't start? Try spraying WD-40 down the air intake as you crank (Don't use ether starting fluid, it will cause damage). If it starts, but will only run a few seconds until the WD-40 is gone, you have a fuel problem. If not, I'd check the engine compression. Best of luck.

Warrenator
October 2008