Heater Installation Guide

Heater Installation Guide: Ski, Wake & Watersports boats and runabouts to 24ft

Installation Considerations

Small boats can present a challenge for heater placement, a challenge that actually launched Xtreme Heaters, with the goal of building an effective heater that would fit in any engine compartment. The result is the most compact solution on the market.


Choosing the right mounting location for your heater is all about airflow. While air will circulate throughout the engine space, you should try to direct the flow as close to the most critical components as you can.

Inboard Powered Boats (Ski and Wake)

Inboard powered ski boats or wake board boats come in two flavors, direct drive and V-drive.  Classic ski boats tend to be direct drive, with an engine “hump” in the center of the boat.  Wake board boats are often V-Drive, with the engine mounted close to the transom, under a sunpad.  Brands such as Malibu, Mastercraft, Supra, Correct Craft, Tige, Moomba, MB Sports, etc are configured this way.  On these boats, place your heater as low in the engine compartment as possible, directing the airflow toward the engine, and if possible below the engine.


Direct drive ski boats, with center mounted engines and “hump” engine covers can be the most challenging to find a mounting location for, but there is generally enough room in front of, or behind, the engine, depending on the layout of the engine compartment for the heater.


Inboard/Outboard, Stern Drive, Outdrive Powered Boats

Most bow riders and deck boats fall into this category.  The motor is mounted in the boat, connected to an outdrive or stern drive that protrudes from the transom.  Runabout and deck boats built by Sea Ray, Regal, Chaparral, Monterey, Larson, Crownline, Four Winns, Bayliner, Glastron, Rinker and others fall into this category.  Current engine brands include Mercruiser and Volvo Penta and there are OMC and Yamaha models still found in older boats.


For a runabout with an inboard/outboard power plants, direct the flow toward the outdrive connection to the engine. The exposed outdrive can conduct cold into the engine compartment. This is particularly true if the boat is stored out of the water on a trailer or lift. In the right conditions, wind can direct cold air through the propeller exhaust port, up through the risers and into the engine. If your boat is stored on a trailer or lift, it is a good idea to cover the propeller/exhaust opening to prevent air intrusion.

runabout heater install


Keep the boat covered

Keeping your cockpit cover on the boat will help preserve the heat, reducing heater runtime and maximizing effectiveness and efficiency of your heater.  Covering the vents that provide fresh air to your engine also helps keep the warmth where you want it. Some customers have had snap-on covers made that work well for this purpose.  Others have used shrink wrap tape with good results.


Testing Your Heater

The LED power light on the back of all Xtreme Heaters indicates that your heater is powered up and ready for use. Learn more about testing your heater.

ski thumbnail

A few more warm and sunny Indian Summer days of skiing

Your dandy little heater will be protecting the precious Holman Moody Racing Engine in our Ol’ vintage ’75 Mastercraft ski boat in hopes of a few more warm and sunny Indian Summer days of skiing. Then I’m thinking of using it in combo with a timer to preheat my truck cab this winter.


— Tony T