Sounds like a wonderful place to be, however would be better with the generator running. Several things to check, I know that tools are limited so keep it simple. Good sign is that engine runs, although with surge, indicating good spark coil, plug and wire.
Usual problems for the engine surging or searching are:
Air filter is wet with fuel or water, causing rich condition. Test without filter. If runs better, clean filter with gas and let it dry before install.
If the engine runs worse with out filter indicates lean condition. Adjust lean rich mix screw or adjust fuel bowel level up just slightly (check for debris in needle seat, clean main jet and check for restricted fuel filter). Lean condition can be verified by applying choke slightly and will make improved performance.
Water in fuel. Look into fuel tank for water (will look like bubbles at the bottom). If water in tank, **** out with short piece of hose, then try to get water out of fuel bowel by removing bowl nut.
Fuel is old. Good fuel will feel cold.
Fuel vacuum lock. Gas cap seals too tightly not letting in air/venting.
Restriction in the muffler. Remove outer defector and check for spark arrester clogged. Remove screen /clean.
Low compression. Need special tools to clean and adjust valves. Verify low compression by pulling the rope slowly thru compression. There should be considerable resistance as you pull thru the compression stroke. If pulls easily, compression leaking past valves. Adjust valves with slightly more clearance.
Post your question on the free advise section of this forum. Then read the same answer and follow the simple test procedures to clue in on engine searching problem. Re-post with test results. The point is to get your gen running out in the middle of the ocean with very little tools avail. Good luck with trip
Just a note to pass on to your friend. The module controlling throttle and throttle motor were designed to be more fuel efficient then the old mechanical governor. We have repaired several of this type of gen (mostly Honda) and have not found fault in the electronic components. The only variable is the fuel (old fuel, low octaine) and fuel delivery system (mostly carb/jets). We recomment that customers use high quality fuel(premium fuel will have longer shelf life) and filter the fuel before adding to gen thru lint free cloth or funnel with fine mesh filter. This engine is very stingy with fuel. It has very tiny fuel passages that clog easily with varnish or dirt. We find that the searching is caused by fuel problem. The engine is not recieving perfectly metered fuel thru jet. It is most likely running ever so slightly lean thus the throttle motor/module cannot find the perfect setting for the electrical demand, thus the searching. As the 17th century sailors would do - knock on the wood hull to check for soundness, today I knock on wood for luck for you sea-fairing friend.
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Now if the genset stabilises with a load but keeps shunting when there is no load it is possible that you need to do a service check or overhaul of the engine.
1. Make sure that the oil is clean , if low or clogged replace the oil.
2. Check the fuel line and the fuel/air settings . If the engine is HUNTING then there is a setting fault of the mixture or there is dirt in the carburator ports that does not allow the fuel to be flowing with the right pressure . It is best to remove and clean the system.
3. The Spark plug is another reason, if the plug gaps are low, if the spark plugs are bad, insulation is faulty the power will be reduced as it will hunt.
4. The genset RPM is monitored by a governor which allows a slight throttle adjustment when the load increases. So make sure that the linkages to the throttle vavle is free and moving.
5. the choke must be kept closed, check the spark plug to have an idea of the firing.Finally check the fuel, check for impurities in the tank.
I am sure one of the above tip must solve the issue.
Thank you for using FIxya.
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This is generic advice that could have been written about any genset and is not specific to the EF1000iS. I do not accept this.
I informed your "expert" that I am not satisfied with the advice I received from Fixya since it was totally generic and reflected no specific knowledge of the model in question. I do not intend to pay.
OK PCTech, I emailed your generic advice to my friend and he says you made some suggestions he had not thought of, so I will accept this. If you look on the Yamaha web site the online parts catalog shows pictures of all the assemblies. The throttle is controlled by a stepper motor driven by the control unit. He was able to get the genset to run steadily by overpowering this motor with a small screwdriver in a friction fit hole.
Most of the suggestions were generic in nature and not what I would call expert advice, but somewhat helpful.
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