Onan 7500 diesel

buzzinhalfdozen · 06-02-2015, 09:12 AM

Gen. set runs OK, produces good power but has always since I've owned it had a "hunting" rpm. Most times it just runs at a constant rpm, but with almost any added load it seems to ramp up the engine speed, at times it will go up and down slowly. Serviced it last fall new filters oil ect. Thought I recall reading somewhere that these basically run at a constant rpm, is this a sign of an issue? Thanks Joe

Rich Biebel · 06-02-2015, 12:28 PM

If it is an Inverter type it is normal. They don't run at a fixed speed and engine speed changes with load demand.

Onan 7500 diesels are inverters usually..

Model Letter code ?

racer3694 · 07-02-2015, 12:53 PM

Quote:

Originally Posted by Rich Biebel

If it is an Inverter type it is normal. They don't run at a fixed speed and engine speed changes with load demand.

Onan 7500 diesels are inverters usually..

Model Letter code ?

I had to replace the brain to my 5500 quit diesel. You want the old box to play with?FREE

06-02-2015, 09:12 AM	#1
buzzinhalfdozen Senior Member Join Date: Sep 2006 Location: Bellevue Ohio Posts: 984 Likes: 0 Liked 11 Times in 8 Posts	Onan 7500 diesel Gen. set runs OK, produces good power but has always since I've owned it had a "hunting" rpm. Most times it just runs at a constant rpm, but with almost any added load it seems to ramp up the engine speed, at times it will go up and down slowly. Serviced it last fall new filters oil ect. Thought I recall reading somewhere that these basically run at a constant rpm, is this a sign of an issue? Thanks Joe __________________ Joe Buchanan SS/BX 3117

06-02-2015, 12:28 PM	#2
Rich Biebel VIP Member Join Date: Jun 2007 Location: Northern New Jersey suburbs Posts: 2,312 Likes: 25 Liked 543 Times in 212 Posts	Re: Onan 7500 diesel If it is an Inverter type it is normal. They don't run at a fixed speed and engine speed changes with load demand. Onan 7500 diesels are inverters usually.. Model Letter code ? __________________ Rich Biebel S/C 1479 Stock 147R