TheWrightMan
New Orleans, LA
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Joined: 12/01/2003
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I have a 1988 vintage 6.5 NHE Onan generator on an '88 motorhome. The problem is the generator will not stay running when I let go of the Start switch. I unplugged the remote switch from the control board and tried it from the local control switch. It has done this before on an intermitent basis but now it seems to be permanent. A few weeks ago it was running fine, powering both roof A/C units. Then it shutdown. I have checked the oil pressure switch, it's OK. I installed a new control board. The carbon brushes on F1 and F2 are OK, when it's running there is 24 volts AC across F1 and F2.
I have a schematic for this unit. Have electrical equipment and meters. Am electrically inclined so I will not bring this unit to someone to repair, unless there is a problem in the windings of the generator. I need to determine what is wrong, so I need your technical assistance on what to check.
What ouput voltage should I see at F1 and F2?
What is Q1 and Q2? What readings should I test for?
Waht is B1 and B2? What reading should I test for?
T2 and T4 are Neutral and Ground
T1 and T2 are the Phases. If they are open will the engine still run?
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Generator Jim
Conway, SC
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Joined: 07/16/2005
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Billy
We would love to give you the parameters you asked for but it is difficult because you did not post the COMPLETE model number. ONAN made spec letters A thru M (I think) of the NHE. There are at least three different stators and two different rotors in that pile. Which one is yours??
JimL
Jim & Jane Latour
08 Chevy 3500HD, crew cab, dually, Duramax/Allison
05 Wilderness Advantage AX6 365 BSQS, Onan 3.6KY
Retired AF CMS (E9) Power Generation and Onan RV genset Level III tech
Grand Strand Sams
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TheWrightMan
New Orleans, LA
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Joined: 12/01/2003
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Jim,
Here is all the data:
Model 6.5NHEFA26100D
Serial F880134321
New local control board from Onan installed yesterday.
Oil switch checked with an Ohm meter.
Brushes fro F1 and F2 removed and inspected.
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gunny357
North Carolina
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Joined: 04/06/2005
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Should be DC across F1 and F2. Read it again and see what you get.
Remove either F1 or F2 and ohm through the rotor. What do you get?
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TheWrightMan
New Orleans, LA
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I do have 11-12 VDC across F1 and F2.
Checked T1 and T3 with Ohm meter. Winding are closed. That's good.
Only 30 VAC out of T1 to Gnd and T3 to Gnd.
I suspect what ever the problem is that it is something that is intermittent, like a relay or bad connection. The reason, is because it has been doing this for sometime and the other day it ran fine.
Suggestions or next checks?
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gunny357
North Carolina
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Ohm value across F1 and F2? That would be the resistance through the rotor.
Now you indicate that this is an intermittent problem. Are the brushes free in their holders? Not sticking or binding?
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TheWrightMan
New Orleans, LA
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That's correct. The rotor is good. Brushes are free.
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kjames90755
Signal Hill, CA
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Check the fuel line to the genny...my MH tech was working mine the other day while making customizations for us and noted that the genny didn't start on the walkthrough--he looked at the fuel line and found a crimped fuel line--now it's fixed and works fine.
Taking back Tuesday for a trip Wednesday! 
2008 Itasca Meridian 37H, All. 3000MH (6-auto), Freightliner XC Chass., Cummins 6.7L Turbo, (Sweet! Delivery 03/12/08). Tow: '07 Dodge Gr. Caravan, Me, Him; Sugarbear, Apr. Toy Poodle; Pepe, Blk Toy Poodle; Hero, fat Siam.-mix polydactyl cat/Alarm Clock.
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TheWrightMan
New Orleans, LA
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Joined: 12/01/2003
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Can't be a problem with the fuel line. The unit runs as long as the Start button is pushed in. But as soon as it's released it stops.
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