Cannot reach rpm (new motor)

[jtim]

I have a new 8hp two stroke mercury on a 17ft Osage cargo canoe. My problem is I can't reach full rpm. The motor is obviously lugging. I have tried several tests. Alone in the canoe the bow will not go down. With my son in the front and the deep cycle battery the canoe tries to plane and runs about 12 mph. I weigh 180 lbs and sitting in the front with my son driving the canoe runs 13 mph. With my son in front and me driving, if I shift my weight forward the motor comes out of a lug and the speed increases 2 mph. <br /><br />Could this be a prop problem? If so, how is best to learn which prop I need?<br /><br />Thanks in advance for all help.<br /><br />Tim Grant<br />Greensboro NC

 

[bluebyyou]

Re: Cannot reach rpm (new motor)

I'm not much of a canoe guy but if this was a ski boat I'd say you're way over propped. What pitch prop are you running? I'd find a prop shop and swap out my prop for a lower pitch and see how that does. Be careful not to over-rev your little motor with the new prop.

 

[jtim]

Re: Cannot reach rpm (new motor)

I got you on the over revving. From what I've learned from this forum today I believe the prop is the problem. I'm looking for a tach so I can make an educated choice. What would be best to do for a portable engine? I read of tiny tach's for mercury. Is this a good choice? Is there another choice that's better.