Originally Posted by Kingly
One concern I do have is the running costs for a 90+ hp. Could anyoe offer guidance on average fuel used and servicing costs. Thanks.
There is a ribnet rule of thumb that most boats cruise at around 1 L/NM almost regardless of size or engine. Obviously there are variations (+/- 20% even on the boats that follow the rule). Above about 50 HP the rule usually seems to apply. If you are speed hungry, taking out heavy divers etc the rule may not work.
There is also another rule of thumb that for each 10HP of engine it will use 1 US Gal per hour at full throttle, i.e. 34 L/h. A 4 stroke may use a bit less than that, but for budget purposes it works!
Servicing costs probably don't change much from 40-100 HP since its mostly time for taking it apart and replacing the impellor and generally checking it over. I'd expect to pay £100-200 depending on age/condition/local competition etc.