I have a fuel problem. My 3cyl yanmar GM30 cuts out when put in gear unless throttle is advanced immediately. I have replaced injector nozzles , fuel filters and the fuel is fresh. I do not know if this is a governor problem or if there is an adjustment in the governor.If someone would b kind enough to help this would be most appreciated.
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Check propeller and shaft for fouling.
Check your propeller for fouling. I had a similar problem once where engine ran fine but stalled when put in gear. Turned out a piece of rope had become wrapped tightly around prop shaft, not propeller blades, such that friction of wrap was stalling engine.
Check your propeller for fouling. I had a similar problem once where engine ran fine but stalled when put in gear. Turned out a piece of rope had become wrapped tightly around prop shaft, not propeller blades, such that friction of wrap was stalling engine.
How long ago did you replace the injectors?
why did you replace the injectors? Did you have this problem before you replaced the injectors? Is your engine's idle speed the same as it was before? ... or now lower? Your symptoms to me sound like that you possibly still have some air ... between the injection pump and the injectors. If all the 'externals' are good to go, then I'd start to suspect a blown head gasket, etc.
why did you replace the injectors? Did you have this problem before you replaced the injectors? Is your engine's idle speed the same as it was before? ... or now lower? Your symptoms to me sound like that you possibly still have some air ... between the injection pump and the injectors. If all the 'externals' are good to go, then I'd start to suspect a blown head gasket, etc.
Crush washers
While it is hard to diagnose a problem like this from afar, another thing to check is the crush washers under the injector nuts. If you've had to bleed the high pressure side of your fuel system, it's always a good idea to replace these washers at the same time. If you try to keep using them after bleeding the system a few times, they can let small amounts of air into the system -- and kill your engine. And, they are cheap...
While it is hard to diagnose a problem like this from afar, another thing to check is the crush washers under the injector nuts. If you've had to bleed the high pressure side of your fuel system, it's always a good idea to replace these washers at the same time. If you try to keep using them after bleeding the system a few times, they can let small amounts of air into the system -- and kill your engine. And, they are cheap...
Possibly the wrong filter.
On either the primary or secondary filter, if the wrong-sized micron filter were used (i.e. smaller than 10 microns) then you will be starving your system of fuel.
On either the primary or secondary filter, if the wrong-sized micron filter were used (i.e. smaller than 10 microns) then you will be starving your system of fuel.
After the crush washers...
The crush washers are a cheap fix and are most often the culprit in admitting air into the 3GM system. The 3Gms are not nearly as fussy about a little air as some other engines and will start but not run well. If that does not fix the problem, you may need to check a bit of your fuel system routing. This problem crops up in the Catalinas built a few years before and after 2000 now and then. It can be caused by a defective check valve. It is a Yanmar design, but I don't know if it was adopted by all boat builders. There is a fuel return from the engine to the tank with a check valve. When the check valve fails air can move back up the lines from the tank. It exhibits itself most when the engine is not run frequently or hard. Early recommendations by Yanmar were to replace the valve. Consensus of those that I know of who dealt with the problem was to remove the check-valve and reroute the fuel return. If memory serves there is now just such a procedure on the Yanmar tech site. I've been lazy on mine, I just give the Racor three or four strokes on its internal pump and the problem disappears for a few weeks. Not a recommended cure, but not bad for a short term band-aid.
The crush washers are a cheap fix and are most often the culprit in admitting air into the 3GM system. The 3Gms are not nearly as fussy about a little air as some other engines and will start but not run well. If that does not fix the problem, you may need to check a bit of your fuel system routing. This problem crops up in the Catalinas built a few years before and after 2000 now and then. It can be caused by a defective check valve. It is a Yanmar design, but I don't know if it was adopted by all boat builders. There is a fuel return from the engine to the tank with a check valve. When the check valve fails air can move back up the lines from the tank. It exhibits itself most when the engine is not run frequently or hard. Early recommendations by Yanmar were to replace the valve. Consensus of those that I know of who dealt with the problem was to remove the check-valve and reroute the fuel return. If memory serves there is now just such a procedure on the Yanmar tech site. I've been lazy on mine, I just give the Racor three or four strokes on its internal pump and the problem disappears for a few weeks. Not a recommended cure, but not bad for a short term band-aid.
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