I have an older model stejcraft stallion 5.2 mtr cuddy cabin and need to know the weight of the boat and it has a 75 yamaha motor

Most likely, (1) it's an old worn out battery, low charge, poor or corroded cable connections. Inspect and clean them. You may want to jumper battery with your car battery. If problem persists, (2) check starter solenoid connections and output connections. (3) As a last culprit, it could be a bad starter. And make sure your engine is not frozen. (Take spark plugs out and turn the flywheel by hand).

There is no fuse box, they use inline fuses. Chase the wiring back to the battery, somewhere near the battery or the radio/fish finder will be a fuse on the power wire.

FourStroke 150 hp - Mercury Marine

https://www.mercurymarine.com/en/ca/engines/outboard/fourstroke/75-150-hp/Mercury FourStroke outboard motors are incredibly powerful and efficient, and they feature a wide range of applications. Crafted for less weight and high displacement, they generate abundant torque and immediate power. ... 150 115 90 75. HP / kW‎: ‎150 / 110
Engine type‎: ‎8-valve single overhead cam ...
Dry weight *Lightest model available‎: ‎455 lbs / .

the weight of the motor will be obtainable from the Yamaha web site in the specifications section the weight of the boat is any body guess as you didn't give a manufacturer name
most marine shops will get close as they are familiar with boat constructions and supply trailers to suit

if you cannot get the details from the manufacturer of the boat and it is not on the compliance plate that should be attached to the boat( plate shows length, max hp motor to be fitted , registered no of passengers possible ,weight etc ), the only thing left to do is to put it on a trailer that is big enough and have it weighed at a public weigh bridge /station
you will be expecting a weight in excess of 1.5 tons or 1500 kgs
most 20 ft boats run on a tri axle trailer because of the weight and length

Undo gearbox bolts,take off trim tab,undo bolt in trim tab cavity,disconnect speedo tube,pull off gearbox. You will see pump housing,undo 4 bolts,pull off housing exposing impeller,there maybe a clip on top of impeller depending on model,pull off clip then impeller.yamaha didn't make outboards in 75

you might want to post this in the boat section

reg unleaded gas.

You haven't specified as to its year of manufacture, so if its older, as in a 2 stroke, it'll be a mix of gas and outboard oil.

If its a newer model, a 4 stroke, it'll be injected(Gas and oil seperate)

If you are totally unsure, Consult your owners manual and if you have none, then any Yamaha dealer can use the serial # off the motor to establish any specs on it for you.

Happy boating.

The two daughters cross first, one returns. Mother crosses, alone. The first daughter returns, both daughters cross.

W/D