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post #16 of Old 12-20-2012 Thread Starter
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Re: Full throttle needed to start Yanmar 2GM20F

Originally Posted by Faster View Post
Yes.. in either case the RW is pumped through the engine (RWC) or a heat exchanger(FWC) and then is injected into the exhaust system to keep the noise level down and to cool the exhaust run out to the transom.

The water is driven out of the exhaust system by the running engine's exhuast gases. If the engine never catches, the rotating RWpump will fill the muffler, eventually possibly backing up into the exhaust manifold where it will find an open exhaust valve and run back into that cylinder. This can cause 'hydrolocking', where the engine won't turn because it can't compress the liquid pocket in the cylinder.

I'm still leaning toward a faulty injector, certainly it's the top candidate for the 'hammer' sound while running.
You just gave an excellent reason why I need to fix the starting issue. Water in the head at the valves and hydrolocking can result in some costly damage, aside from getting stuck somewhere and losing a good part of the season. Thanks, for the input.

I agree about the injectors. The way I understand it the injectors are the only thing that could be allowing too much fuel to get in the engine and cause fuel knock. If the Injection pup was failing that would result in not enough fuel. Are my assumptions right?
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