Gear ratio force 70

[jakutija]

From almost got forse 70 hp, 1995, the propeller pich 13 is too much for my aluminum boat, not to exceed 3000 rpm, when I checked, I see that the gear ratio 1: 1.55, is it possible that the engine has a gear ratio 1: 1.55 . The menu is amazing, if there is such a gear ratio or is it a wrong gear box.

 

[pnwboat]

My manual shows that the gear case on the 1995 70HP motor is 1.64:1 ratio. If your motor will not go above 3000 RPM's with a 13 pitch propeller, then I would suspect that you may have a problem with the motor. What is the length and weight of your boat?

 

[jerryjerry05]

Do a compression and spark test.
Is the motor mounted righ​t?
This the motor that came with the boat?
Trim@tilt?
Size and load affect the rpm's.

There is no engine ratio.It's a 1
The gears are where the ratio is.
The 1.55 to 1 is every time the motor goes around once.
The prop goes around 1 and a little over 1/2 revolutions.

 

[roscoe]

Yep, sounds like its firing on only 2 cylinders, or is seriously starved for fuel.
Compression and spark test will likely reveal the issue.

 

[jakutija]

Yeah, that's 1.64 ratio.
Compression is ok, about 120 in two three-cylinder.
A spark is present on all cylinders, the fuel is not missing, consumes about 7 gallons per hour.
Works well on idle.
The boat is 18 ft, 850 p, weight. Nothing is clear to me.
I need to check the stator and provided a spark at the right time.