yanmar trouble

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  #1  
Old 10-25-04, 10:18 PM
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yanmar trouble

O.K. Here is the problem. At work there is a small single cylinder yanmar engine. It is a diesel engine and it is hooked up to a cat pressure washer pump. The problem is that the engine is hesitant to start up. Once it is started it runs great and takes the load without trouble. I figure it is either a compression problem, injector pop pressure problem, or possibly a fuel pump timing issue. I don't have any manuel or testing equipment for yanmar engines. I do remember at school there were two old yanmar engines that were brought in and they fought them for the longest time. They adjusted the fuel pump timing, checked the injectors, and even changed the pistons, but they never could get them to start. Are yanmars that troublesome? I know dixie chopper uses them so they must have some good ones out there. Any advice is appreciated.

P.S. I thought a briggs with a sheared flywheel key kicked hard, these yanmars are a beast to pull start.
 
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Old 10-26-04, 01:56 AM
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"P.S. I thought a briggs with a sheared flywheel key kicked hard, these yanmars are a beast to pull start."

I bet!!!! I have never started one. I assume this engine has no pre-heat source, like glow plugs? All the things you mentioned can affect the ease of starting on a diesel. You'll have to have a lot of compression for it to start, especially without a glow plug. A leaking injector may cause the pump to lose it's prime a little, making it hard to start. A bad injector spray pattern will also cause hard starts, and will also ruin the piston in time. You can probably start it on the first pull with a gassy rag over the intake, but gassy rags are dangerous and this shouldn't be necessary. Injector pump timing can be tricky, and if it is running right, you're probably best off to leave it like it is unless you get a manual with the specs.
 
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Old 10-26-04, 03:59 AM
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I almost hate to mention ether since everyone seems to goes overboard using it. Spray a SMALL shot of eather at the intake, set the can down and try to start it. I tell you to put the can down because most people want to start spraying constantly while cranking the engine. Big mistake.

A diesel is very different than a gas engine. It's speed is controlled by the fuel supply. Ether is the fuel supply and you are bypassing the rev. limiter. Too much ether can cause the engine to rev out of control.
 
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Old 10-27-04, 01:33 AM
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Not to mention that ether is harmful to diesel engines.
 
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Old 10-27-04, 03:35 PM
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Yep Cheese. Ether can make almost anything run, but it can kill an engine very quickly.


Two years ago I went to buy mulch on a cold November morning. The idiot at the nursery hosed the intake of their Cat. front end loader with ether. He cranked it, and the engine rapidly over-reved, made a loud bang/clank and died...
 
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