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Hank F.
Hank F., Technician
Category: Small Engine
Satisfied Customers: 15187
Experience:  Certified on Onan and Generac generators
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How do you change the spark plugs in a Onan 7000 Generator

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How do you change the spark plugs in a Onan 7000 Generator?
What is the full model number of your genset?
Customer: replied 8 years ago.

7HGJAA-97A I think, does that sound right. The generator is used in the motorhome and it looks like you have to take the engine out to change the spark plugs in the back. Does it rotate, turn or slide to make it easier to get to the back spark plugs? I have the book but nothing in the book gives us the procedure. Thank you


No, you should not have to remove the genset. The right plug is located directly behind the right valve cover. It is the hex shaped piece of aluminum on the right, about 2/3 of the way up the motor that says 'Onan OHV'. The plug boot (the rubber piece) can be a bear to get off. Get hold of it and turn it to break it loose. It will pull off, but you may need to use a pair of needle nose pliers to get it off. If you use the pliers, grasp the boot as close to the engine as you can, and pull gently so you don't tear the boot.

Depending on how the set is mounted in your coach, you may have to remove the air filter and air filter rear housing to access the left plug. It will be situated directly behind the left valve cover.

They can be a little rough to get at, but you should not have to do anything drastic to get them out.

If you want a drawing of where they are located, I can scan one in and post it here.


Customer: replied 8 years ago.
Thanki you. If you could post the drawing that would be very helpful. We will give it a shot. thanks again

Not a problem at all. Give me about 10 or 15 minutes for fire up my scanner.


Ok, here is the drawing. This is an overhead view, like you are looking down at the top of the genset. The square box at the bottom left corner is your air filter housing.

To see the drawing, click here.


Hank F. and other Small Engine Specialists are ready to help you
Customer: replied 8 years ago.
Thank you It is perfect!!
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