Originally Posted by Frogwatch
That li'l YSM8 is a simple engine and should be ultra-reliable.
Describe "running away" Does it happen only in gear or does it ever happen in neutral?Could it be a situation of the shift button jumping back into neutral and then speeding up cuz no load?
Why doesn't your choke cable work to shut her down? Even if the cable doesnt work you can go in the cabin and manually do it rather than putting something over the intake.
Get to know yer engine and eventually will fall in love with it for what it is, a simple piece of equipment that works most of the time with the right maintenance. Be sure you know how and why to bleed the fuel system. Do it numerous times so you know what to look for with air on the lines. Be sure you know how to change your intake impeller (it has been changed hasn't it?) and take a spare impeller. Take a spare water pump /alternator drive belt (they are prob separate). When starting up, ALWAYS look behind for the cooling water coming out the exhaust. What color is your smoke?
There is no real exciseable patter to discern. Ive ran the engine hours with no issue. Ive run it two minutes and it run away. There is no pattern other than a flucuating of rpms followed by a sudden and immense upswing in rpms known as run away.
It has happened in neutral as well, which is so much more dangerous since it would rev up until explosion. The smoke starts white and goes grey to black. Also you can smell diesel and see diesel in the water behind the boat. Choke cable doesnt work bc diesles run off compression not injection. Cutting gas will do nothing, must kill air intake. I do have spares for everytinh on the engine so far as filters belts impellers and gaskets. I purchased a complete anmar kit from french ltd motors. I am blessed to have a family member high up in the boating industry. A specialized yanmar mechanic is coming down to find the problem and solution. Family is a blesssing like no other. No worries about the chesapeake, i lived there before. Too cold for my southern blood. Does that mean i can tell you to stay out of fl? I think you get the crap end of that deal..