This depends on the size of the boat. The smaller type such as 12 foot row boats will usually have 7 hp outboard motors. Some of the larger boats up in the 20 to 30 feet have been known to run up to 4 outboard motors around 300 hp plus each. Above these boats in lengths you will find most of them run large diesel motors cummins, Caterpillar, detroit(mtu) and Volvo's. Some of these larger 2000 to 2200 hp motors power these luxury yachts. Hope this answered your question
Most speed boats, especially with outboards, use gasoline engines. Larger vessels such as ships and commercial boats, generally use diesel. For raw power and performance, gasoline engines are still best. Big chevvy V8s are popular choice for powerboats with internal engines. Water and electrics (for the spark) do not mix well, so gas engines need to be maintained and looked after well and can be temperamental. For economy and reliability diesels are best. Which is why commercial vessels use them.
powerboats
Speed Kills - The King of Powerboats 2008 SUSPENDED was released on: USA: 2008
Thrill Zone - 2005 SOS Extreme Powerboats was released on: USA: 1 August 2005
Because engines are big and bulky.
The Cheverolet big-block engines were developed during the 1950s and the 1960s. The big-block engines where developed to keep up with the larger vehicles that became popular during that time.
the engines
Steel Dreams - 2001 Poker Runs and Powerboats 5-9 was released on: USA: 1 October 2006
They once were very big. Today they aren’t.
A big block is a series of large displacement V8 engines.
Because people are willing to pay for them.
Just one big one