motor rev

[red apple john]

two questions
iIhave a 1999 merc 40 HP. Should I use mid grade or
reguler gas?
Went out today and it ran fine at low speed moved the throttle
for more speed and it act like the prop stopped and the motor reved up.
lower the throttle and it ran fine. Any help.
Thanks, John

 

[guyjg]

[QUOTEShould I use mid grade or reguler gas?][/QUOTE]

regular 87 octane gas

...act like the prop stopped and the motor reved up.

Change the prop; it's slipping.

 

[galamb]

Yep