Generac Generator GP7500E Rebuild

[monster318]

Good Morning all,
I recently acquired a Generac 7500 Watt generator for $75 that has sat outside for the past few years. The fuel tank was rusted and full of water, and the piston was seized in the cylinder with heavy rust and water damage to the cylinder walls. The generator end was like brand new however, looked like it never had a drop of water in it. I got the cylinder honed clean, all the other parts cleaned up very well. I cleaned the fuel tank out with a muriatic acid and water mix, which worked surprisingly well. I got a new piston, rings, and complete gasket & seal kit for it.
I am ready to begin putting this back together; however Generac doesn't have a tech or service manual online to provide the specs of things like connecting rod cap torque, head bolt torque or valve lash. I contacted Generac via both email and phone call to inquire about this info or a tech manual. They informed me because I am a homeowner and not a certified service location for Generac that they cannot release such information to me.

Really not sure where to go from here, any ideas?

 

[big bubba]

have a Generac 6500w unit. the manual calls for .004" for exh/int valve lash.
the following table might be a starting point for head bolt size torque & connecting rods. assume you already have an accurate torque bolt wrench, good luck
http://www.ntractorclub.com/howtos/pdfs/Torque-Values-for-Common-Bolt-Sizes.pdf

 

[WranglerX]

It's possible your Generac unit was not made by Generac... I have a 6500 watt unit and Generac claims by the model number it was manufactured by Briggs & Stratton (For Generac?) and suggests I contact B&S for information.......

IF nothing else I would use "standard" (SAE) torque settings for bolt grade and diameter.... I know it has to be reliable and serve you for long time, but it's not a space shuttle....

Dale

 

[RandyT]

Get me the actual model and serial number off of the tag on the frame and I can look it up. I am an authorized Generac portable dealer. If this is the Rato 420 engine info may be limited.

 

[monster318]

Thank you. This is the tag on the frame.

 

[RandyT]

Generac doesn't list that service manual on the dealer site. I will call my service distributor tech support tomorrow and see if they can find it for me.

 

[WranglerX]

Might look here........

https://www.generac.com/service-sup...roductid=c01594f5-a456-47d5-8a15-55a21aa4d257

Dale

 

[RandyT]

There is no direct information for the Rato engine on this model. From what I and my parts distributor/tech support can come up with is use the information for the 426 engine which is .002-.004 valve clearances and 18 lb-ft for the rod bolts,and 30 lb-ft for the head torque.

But wouldn't hurt to double check the standard torque spec by bolt size for comparison.

 

[dfkrug]

Thank you. This is the tag on the frame.

If you find the emissions plate, you can usually see the actual maker listed. I would have expected the 2-cyl engine on a gen that big.

BTW, I bought a Chinese-made Generac inverter gen a year ago (iX2000), and it failed. Not fixable, since it needed new inverter-rect board. Generac was no help, so I contacted the Chinese factory which made it. They would sell me the board, but wanted to sell me at least 20 of them.

 

[monster318]

Thank you everyone for the help. I did find the valve clearance spec in the owners manual online, its my fault for not reading that thoroughly. Owners manual says 0.006'' for intake & 0.008'' for exhaust. I will check on the bolt size torque specs for the rod cap and the head bolts. I plan on having this be my rainy day project tomorrow so I will update tomorrow evening hopefully with good news.