sluggish ysm-12

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Nov 26, 2006
381
Hunter 31 1987 Fly Creek Marina Fairhope,AL.
I have a 1979 YSM-12 that is very sluggish when advancing the throttle and sometims just dies. Ir starts fine and idles ok for a while then wants to die if I give it some throttle. I have changed the fuel filter on the engine and bled the racor water seperator but still same problem. There is no line fowled on the prop and its turning free in neutral by hand. Any comments apreciated. Also there is little smoke if any but just a little blue smoke occasionally. Could it be the mixing elbo is clogged or should i change injectors? Thanks
 
Dec 3, 2003
2,101
Hunter Legend 37 Portsmouth, RI
Blue Smoke Indicates Oil...

How old is the motor? Model? Maybe it's losing compression? Maybe a mechanic should give it a look/see? Possibly an oil analysis will tell you? Lots of questions.
 
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steve rainey

ysm12

I also have one of these. When I bought the boat it would rev up to where I though the thing was going to jump out of the boat. turned out the governor was sticking. I compared with others it revs up the same. Two things I learned right off the bat with this engine is when changing oil, be sure the you don't fill it all the way. Leave it just below the fill level otherwise it will start to burn it as fuel and won't run right. This is a known problem with this engine. The other thing I learned quick is to keep the mixing elbow clean. Mine was plugged. Had to put a new one on which also included the exhause manifold. I put the new mixing elbow back with lots of anti sease for the next time. Without it you'll crack the manifold when trying to take the mixing elbow off..
 
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steve rainey

ysm-12

another thing, I tossed my alum tank and put in a poly one. no water no condensation. it runs better also with new fuel, I noticed a difference.
 
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