How big of an engine would you put on an 18' pontoon?

Question

It currently has a 35 hp Merc, but I want to go bigger. As big as I can and still be able to handle it safely.

Answer 1

The pt will only go so fast> More power will only make it deeper in the water. The tag will tell you hp rating>

Answer 2

Never exceed the power rating on the hull tag. Pontoons are notorious for having weak transom areas. A larger motor than it is rated for will, at most burst the transom, and at least cost more to buy and operate. Pontoons do not have performance hulls so more power does not translate into more speed. They can be made to go faster but they lose most of the stability when they do. An overpowered pontoon sets very low in the water at rest and at speed, the torque of the engine c***s the boat severely to the right making it uncomfortable to drive or ride in.

Answer 3

Check your USCG label, but most 18ft pontoons today can handle a 50hp and that runs real good on an 18ft.  If you can handle a 60hp then it won't increase the weight from a 50.  They are the same weight (same powerhead).

One thing to consider is the year of your current engine.  If it is older that a 1990 than the horsepower was rated at the flywheel.  Today they are rated at the prop.  so your 35hp is equal to a 28hp today.  Food for thought........

Answer 4

Try a 250 Verado and let us know what happens. LOL

Answer 5

IMHO, you are pushing the upper limit right now. Maybe a 45 or 50 if you really know what you are doing. Pontoons are not built for speed, they are built to cruise, so getting one up on plane is not a great idea. Once saw a small pontoon so loaded with people the 'toons were under water. Needless to say the Water Patrol stopped them, and discussed the theory of displacement.