Yanmar help needed

[Pa La O La]

Good day to all,

Well here is the deal I have a 3GM30 Yanmar. The problem- after 30 or so minutes working under a load the engine when brought back to idle detent on the throtel/shift control drops below idle set RPM and wants to die. A quick push of the shift release button and throttle advance the engine will idle with the throttle advanced. If I am to slow on this maneuver and the engine does happen to stall out, no worries because she will start right up every time (so far!) but as you might imagine this can make getting backed back into the slip a real chore and a bit nerve racking. I have cleaned the tank, fresh fuel, filter boss for quick filter change while running. New hose from tank to engine, new engine fuel filter, new high pressure lines from injector pump to new injectors. Injector pump serviced at dealer. Mixing elbow clean and engine heat exchanger removed and cleaned out too. This is not accompanied with any unusual smoke or noise. When the engine cools back down. Right back to normal. So what’s left, I think I’ve covered Fuel, Fuel, and Fuel. The cable isn’t hanging up. Have you ever heard of this before?

[never monday]

governor adjustments. This should be done by a Yanmar tech

[Pa La O La]

Good day to all,

So I am all but convinced that what I have is a governor problem. What I’m not to sure of is how to approach it. Is it the springs that are going bad or is it the centrifugal throw out on the crank shaft. Something is not moving the rack to where I get enough fuel to keep it idling. Again it is only after the boat is been worked under a load for a while. I have heard of the springs going bad but I don’t know what the symptoms are. Has any one had their governor serviced? And if so what was the problem? I’d love to hear what might be done. I’ve replaced the fuel system from the tank to the cylinder. Clean fuel is not a problem. Has anyone had governor trouble? If so what were the systems and the solution? Thanks for the help

Gary

[never monday]

Originally Posted by never monday

governor adjustments. This should be done by a Yanmar tech

quoted for clarity

[Chief Engineer]

the injection pump?

Originally Posted by never monday

governor adjustments. This should be done by a Yanmar tech

Originally Posted by never monday

quoted for clarity

[Alan Wheeler]

Injector pump serviced at dealer.

Was this serviced because of the problem, or did the problem occur after he had serviced it.

Second question, are you sure the idle limit is set correctly? Have you tried to adjust the idle limit? This is a small screw that becomes the "stop" or "rest" for the cable/clevis to fall against.

If you do adjust it, does the engine then rev to high at idle when cold?
There is often a slight difference between hot idle and cold idle. But the norm is that the engine should rev slower during a cold idle and slowly pick up pace as it warms up.

[Pa La O La]

I had the injector pump serviced because of this problem and it had never been serviced before (1993). I replaced the high presser lines and injectors for much the same reason. A bit of rust here and there on the lines. Getting the boat ready for a bit of extended cruising. We both retire again this time next year. I like to do all the work I can now so if I really break the thing help is a call away not days and miles. I used to fix jet engines so I’m ok with a wrench. The trouble stared before the work not after. She runs smooth. The idle set is good cool against the stop. Just not after warm. I just have to advance the throttle to keep an idle after she is warm. Stating, running -she purrs. Cooled off and everything is good again.

[Pa La O La]

Originally Posted by Chief Engineer

the injection pump?

As to have I fiddled - NOT YET !

[Chief Engineer]

If you have removed the injection pump before and re-installed it yourself then you know that the "fork" has to engage the "rack". If you remove the injection pump and look at the "rack", when you turn the pump 90 degrees the rack should move. There should be no binding.

[Pa La O La]

I installed the pump and did the timming (shims) Started first time. Careful to get the fork huuked up right. The thought of a run away can help keep your focus. Did not bind. I have been wondering if when she gets warm that might not be the case. Would the pump be tested at running tempture?

[eltigre]

Sounds like you have worn parts in the governor. I also recommend having a Yanmar tech look at this for you. I have tampered with this before and was unsuccessful on getting it back to the correct place. Tech guys have the correct tools for this.

[Pa La O La]

So,

Back from a trip to the yard to have the standing rigging replaced. Made both bridge openings and turned and parked her in the narrow creek with no trouble. Answer was a one eighth turn back off the fule injection limiter. I've had the boat for over four years and no one else has touched the engine. Why the change I have no idea but I'm one happy camper now. Everyone at the marina can't belive how easy it was to siwing her around in the farway and back straight in to the slip. It is like I have twin engines. (SONIC leg -steerable thrust!) Unlike the all hands docking with a sputtering engine. Yes I broke down and had a tech look at her. Other wise I feared for the yanmar's health and mine. The wife would have killed me if I blew her up or used her for a bottom weight. Fule , fule, or fule. Yea, not enough but why the adjustment? What ever the reason I'll take her running like she is now. Thanks for the thoughts as to the why. It had me stumped.

Thanks

Gary