Backfire

[Guest]

My Yanmar 1GM is hard to start this time of year afterbeing shut down for the night or longer. It catches, seems to backfire, shakes a lot and then dies. Lately it also is sending out a puff of exhaust fumes out of the air intake.When it gets going after several tries it runs fine.It also starts without problem when still a little bit warm. Can anybody comment on causes and cures for the puff of smoke out of the air intake?

 

[Pete]

hard starting

check for a air leak in the fuel system,possible a bad gasket at injector or blead screw not tight enough etc. etc. you also said hard staring this time of year but did not say where you are located so I will assume your are in colder climates and only suggest that yanmar are hard to start when cold.

 

[Steve Dion]

Get a manual too.

You may want to consider getting a Yanmar manual on the 1GM engine. It covers 3-4 of the GM series engines. If you are cranking the engine very long, you should turn OFF the raw water intake. Once the engine starts you can open the raw water intake. DO NOT crank your engine for more than 15-20 sec. at a time. You can/will overheat the starter and possibly burn it out. I assume that the puff of smoke you are seeing is a result of cranking and not starting. Then the engine pushes the exhaust out when you get this back fire effect. Remember that the Yanmar diesel engine is starting the engine on compression only. Unlike some other engines that utilize a 'Glow Plug'.If you have the manual, they explain a cold weather starting technique that has to do with de-compressing the engine. It allow you to spin the engine without compression, which helps pre-oil the engine and changes the timing. You should also move the throttle lever to full open throttle position too.