Can Cummins Onan QG 7000i Dual Fuel replace a Cummins Onan 4000 watt Onan Generator
Updated 04/16/2026 | Published 04/11/2026
Question:
Can Cummins Onan QG 7000i Dual Fuel replace a Cummins Onan 4000 watt Onan Generator on my 2026 SMC 34 foot 3 horse gooseneck trailer with Living Quarters? I have a 15 gallon gas tank installed in the trailer tack room. Thank you, Steve Wernimont Denver CO
asked by: Steve W
Expert Reply:
Great Question Steve,
Yes, The Cummins Onan QG 7000i Dual Fuel part # CM44MR will work well to replace your current 4,000 watt generator in the SMC horse trailer. You’ll be gaining quite a bit more power, enough to comfortably run multiple AC units and other appliances in your living quarters, which is a big step up from the 4k unit.
Where you’ll want to pay close attention is the footprint and overall fit. While the 7000i is designed to fit in similar generator compartments, it’s not identical to your existing unit. Your current 4,000 watt unit is about 30 inches long, 19.7 inches wide, and 14.4 inches tall, while the 7000i comes in at roughly 33-5/8 inches long, 22-1/8 inches wide, and 16-3/4 inches tall. So you’re looking at about 3-1/2 inches more in length, a little over 2 inches wider, and about 2-1/2 inches taller.
Even if your compartment is close, you’ll want to make sure there’s adequate clearance not just for the unit itself, but also for airflow, exhaust routing, and service access. In many cases like this, the opening can be modified or the compartment adjusted, but it’s something you’ll want to plan for.
On the fuel side, your 15 gallon tank in the tack room will still work, which is great. The 7000i uses an electric fuel pump and only requires a single fuel supply line, so you won’t need a return line. It can pull fuel from a tank within about 3 feet vertically, so as long as your current setup is in that range, it should supply fuel just fine. The main thing that may change is the connection itself. This generator uses a 1/4 inch inside diameter fuel hose on a barbed fitting, so if your current fuel line is a different size or style, you may just need a simple adapter or to swap the hose to match.
Another nice improvement is that most of the service connections, including fuel and electrical, are grouped on one side of the unit, which can actually make routing and access a bit easier compared to older models.
Overall, this is a really solid upgrade for a living quarters horse trailer like yours, just plan on some adjustments to get everything to fit and connect properly.
What kind of horses do you have?
Product Page this Question was Asked From
Onan Generator - QG 7000i Onboard RV Generator - 7,000 Watts - Dual Fuel and Inverter - CARB
- Generators
- Inverter
- Gas
- Gas and Propane
- Propane
- 4001 Watts or More
- Onboard Generator
- 120V Output
- 240V Output
- Electronic Fuel Injection
- Electric Start
- Cummins Onan
more information >
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Steve W.
4/16/2026
Heather, Thank you for this thorough response! I was getting different answers from my SMC Trailer dealer and from Onan Cummins. Running one AC unit plus Starlink Satellite, 4 computers plus the normal load from the 15 ft living quarters. I didn’t want to be under powered nor wasting fuel. This makes perfect sense for me and the fabricator doing the install. You’re the best! Steve