I was running my generator to power our sailboat battery charger when I noted a change in the rpm as if it had suddenly been loaded up. Normally the charger doesn't fully load the generator as it's a 20A charger and should only draw about 500 watts. The overload light was not on. I tried to switch the economy mode on and the engine promptly died. After that, when I tried to start the motor, there was lots of resistance on the pull start. I disassembled the generator looking for some possible binding issue and after disconnecting the internal connectors, found that the engine turned over normally. I am able to easily start the motor with the generator disconnected from the control unit. There seems to be a internal load being applied from the control unit. Is there anything I can do short of replacing it? A new control unit is about 80% of the cost of a new generator.
I assume the problems are AFTER the battery charger has been unplugged. If your boat is out on ocean water, I would suspect a wave splash/mist (or many) may have been inhaled thru the inverter cooling air intake while it was running. The salty water evaporating by normal system heat would leave a conductive deposit in places where there should never be one. Even non-salty lake water can cause problems over a longer time period because that water isn't very pure and a semi conductive pathway could evolve and disrupt the electronics. You don't say how old or how many hours it has logged, so it could be a warranty repair.
I would remove the inverter assembly and if you see and suspect a dusty/crusty deposit, wash it in warm water with an old toothbrush dragged thru the terminals embedded in the high quality sealing compound that covers the entire back of the unit. Also do the same for the connectors on the wire harness that plug into the inverter and blow dry everything with compressed air. You can also use contact cleaner, but it's invasive penetrating qualities (compared to tap water) may get below the surface of the potting compound with unknown capabilities for harm ("can" foil capacitors).
The inverter replacement's 80% of new repair cost is the absolute worst attribute of these high tech machines and we all feel your pain and cringe every time we read about this type of $$$ component failure. The fact that the overload light was not on and switching the economy mode on kills the engine does indicate a serious problem.
Talent, On Loan, From God --Rush Limbaugh--
In reply to this post by mikefossl
If you have not done so I would keep water away from any internal parts as I think it will compound the problem, I can see where the writer is coming from though.
I have a similar problem on my EF1000is, exactly the same symptoms. I was really lost until the specialist generating company I bought it from told what to do. Which was to unplug the connectors from the stator, if it pulls over freely the stator has failed. They don’t know why this happens. I simply turned mine off after working fine, on restarting it struggled to run and then stopped, he said this is not uncommon on this machine. As you pull it over the coils produce a magnetic field opposing the direction you are pulling, hence the harder you pull the worse it is, by disconnecting the wiring this is stopped. He says that this problem doesn’t cause any other damage, so replacing ithe stator should do the trick.
I have yet to try, read on.
If it is the Stator Ass, I believe the USA part number is 7VV 871501000 or 7VV 87-150-10-00 , but check, and I have found them on the internet in the states new for as little as $165. by googling the part number
This doesn’t help me as I am in the UK and Yamaha won’t tell me whether this is compatible with the UK model as the output voltage is 240 volts. But I think it is the inverter that determines the output not the stator, either way they tell me. So I am looking at $307 here! I am going to see if I can get it rewound before paying that.
I hope this has been of use to you, but remember I have not yet put it to the test. Let me know how you get on, I’ll do the same.
( also a trailer sailor – Etap 22i)
Has this been resolved? In searching for another topic I found this old post where you mentioned:
" I simply turned mine off after working fine, on restarting it struggled to run and then stopped, he said this is not uncommon on this machine".
He was talking about an alternator stator that worked when shut off, but was binding and dead on the next use of the genny. Guess what happened there. It just hit me how this happened. Engine cylinderhead/crankcase heat (from a sustained heavy load?) will be almost fully transferred to the alternator's much cooler plastic covered wire windings after the engine stops. What makes it much worse is the fully sealed blue plastic enclosure that can keep that heat in place for 1+ hours. This stator killing heat will soften the coating to goo, allowing the windings to short to each other and ground. In my opinion this damage can and will be minimized if you do what I routinely do on my EF1000iS and EF2000iS gennys after I use them.
1--At the end of use (still running) remove electrical loads and shut off the fuel valve.
2--Still running it at no-load to cool the engine/alternator down, using tiny, gradual applications of partial choke just enough to maintain smooth running, just after it starts running erratic. When the choke is almost fully on and the engine no longer runs smooth, immediately push the choke in fast and the engine will stall from fuel starvation (a GOOD thing!). This lessens the full throttle, high RPM full fuel mixture pumping thru the combustion chamber as the engine coasts to a stop.
3--Remove the maintenance panel, drain the carb float bowl.
4--Leave the blue panel off until the engine cools off.
5--Check the cooled off engine oil level before putting the panel back on.
I did it to prevent the trapped heat from aging the internal rubber and plastic parts, not really considering the alternator windings were vulnerable to that trapped heat damage . . . . but from recalling the same sequence of events present before most poster's stator failures, it tells me they ARE! This is very likely what kills too many of the stators, where their failure is only apparent on the next use of the genny, by the VERY HARD pull of the recoil starter.
Talent, On Loan, From God --Rush Limbaugh--
"I have a similar problem on my EF1000is, exactly the same symptoms. I was really lost until the specialist generating company I bought it from told what to do. Which was to unplug the connectors from the stator, if it pulls over freely the stator has failed. They don’t know why this happens. I simply turned mine off after working fine, on restarting it struggled to run and then stopped, he said this is not uncommon on this machine. As you pull it over the coils produce a magnetic field opposing the direction you are pulling, hence the harder you pull the worse it is, by disconnecting the wiring this is stopped. He says that this problem doesn’t cause any other damage, so replacing ithe stator should do the trick.
I have yet to try, read on. "
I had the same thing happen to my Yamaha EF1000is. I came accross this thread and it was absolutely correct. I replaced my stator and the problem was fixed.
My old stator had a burned up section I could see where the copper had gotten hot and was dis-colored. I tried unwrapping the wire on that portion of the stator and the clear coat was badly burned and the copper was hard to un-wind their where it had gotten hot. I think I may have put to much load on the generator and that is what caused the stator to go bad.
I would like to thank the person that posted this post it helped me out tremendously.
In reply to this post by blue14
Since the problem is overheated stator coil windings on a generator that has an electronic overload circuit breaker, it appears to be a design problem with not enough of a safety factor built in. Maybe the stator coil windings do not have a durable enough plastic coating and they short together, decreasing the coil resistance while dramatically increasing the operating temperature. If you're loading the genny with an 850W continuous running load in +90F degree heat in the sun, you can/may/will push the unit to component failure.
In using ALL my air cooled engine outdoor power equipment I employ a 2 to 4 minute (unloaded) engine idle cool down period. Generators, lawnmowers, chainsaws, 4 stroke string trimmer, wood splitter, chipper-shredder and 4 stroke handheld leaf blower. They all benefit from hot-hot crankcase oil cool-down and/or combustion chamber and piston hot spot distortion dissipation which all contribute to varnish build-up and accelerated seal/gasket ageing.
Talent, On Loan, From God --Rush Limbaugh--
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