EF4500ISE auto choke problem?

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EF4500ISE auto choke problem?

BSHGTO
Bought a new to EF4500ISE that has the auto choke this unit starts and runs fine most of the time when camping. On occasion it refuses to start when engine is cold or hot (plenty of gas and oil, less than 100 hours on plug turns over quickly) when I pull the plug it`s obviously flooding itself, any one have any ideas?Of course the dealer can`t find anything wrong because it`s intermittent and I`m tired of running 2 hours to the dealer. Considering the units cost, not a happy camper.
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Re: EF4500ISE auto choke problem?

CycleRob
Intermittent problems are the worst kind!!
There are a few easy shots (compared to a 2hr ride) you can make:

--Reread the owner's manual that explains the starting AND shutdown procedures. They can be critical for properly positioning the choke butterfly for the next startup.

--A low battery may cause the malfunction, but that conflicts with you saying it "turns over quickly". To eliminate it from contention, connect the generator battery with jumper cables to your car/truck (not running!) every time you start the genny. It may take 10--15 starts or more per day for several days to show you results. In that time period, if it floods again and fails to start, it's not the battery.

--There is a THERMO UNIT (p/n 1P5-83591-00-00) that senses the engine temperature, part #48 top-center in the pic below. Being near new, it is unlikely but still possible it is intermittently malfunctioning. The Yamaha tech should have Ohmmeter tested it to see if it is in spec for different temperatures. Check to see it is connected -or- better yet, test it yourself IF you can get the specs from Yamaha. The data should be specified in the EF4500ISE service manual.



Talent, On Loan, From God  --Rush Limbaugh--
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Re: EF4500ISE auto choke problem?

jefgreen
I'm curious if the original poster found a solution....

I picked up an EF4500ise the other week, started with a lot of cranking but eventually would run. Now it wont start at all. I pulled the air cleaner and the choke was open, once closed by hand the generator fires, runs normally and makes power.

I found the Theory of Operation and Troubleshooting manual and did some investigation. The choke servo motor ohms out correctly as spec'd in the manual. In addition I believe I located the temp sensor on the head, and that had a resistance of 5260 ohms at room temp, it should have been about 18-300 ohms if I recall correctly. I put a 350 ohm load onto the harness to simulate a cold start condition and the choke still wouldn't close even while the engine cranks.

There are two posts in this forum about EF4500ise choke problems, any one successfully troubleshot them?

Jeff
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Re: EF4500ISE auto choke problem?

jefgreen
The auto choke and the auto throttle use the same Mitsubishi MP24S 12VDC stepper motor, so I swapped them. No change, choke still won't close but throttle seems fine and unit still produces power.

From reviewing the wiring diagram, the Control Unit sends the signal to the stepper motors, so short of swapping in a new control unit @$1200, I'm not sure how to proceed.

Jeff
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Re: EF4500ISE auto choke problem?

jefgreen
I put a 10amp load on it and it died. In addition to the auto choke, the auto throttle isn't operating either.  Brought it to dealer and they confirmed the control board is toast. Their price is $1795, they can discount it by 10%.

Essentially not financially viable to fix it. Fudge.

Jeff
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