Fine tuning on mercury 8hp???

[eyeskeenas]

Gday folks, i have a 315 allycraft cherokee with a 2010 8hp mercury 2st. with me in it, it runs along on the plane perfectly and im really happy. as soon as i put another person in it i just cant get her out of the water. its so close every time but just cant get that little extra. is there any little mods i can do or checks i can look at just to get that little extra out of her???? your advice on this would be great. thanks in advance.

[upstart]

Reminds me of when I was a kid. I had a twelve foot Clarke tinny with a 3.5hp Mariner on it. It would plane with a skinny ten year old driving but as soon as my equally skinny brother got in it would struggle. We lifted the motor about an inch and fitted a cheap bolt on foil. It made a huge difference. Much better. Then when I was twelve, my grandfather bought us a 15hp Johnson. No substitute for cubes!!!


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I am here: http://maps.google.com/maps?ll=-19.197827,146.678154

[cormorant]

Just some ideas

Lower pitch prop, prop the boat correctly. Will lose a little top end speed but motor will be a lot more comfortable.
Less weight in boat
balance the boat better. Move fuel tank and people
Adjust trim of motor
get motor height perfect
Fresh premium fuel
Better quality oil
get stern lift with either a permarim on motor or perment hull extension like fixed trimtabs.
Lose weight
Get thinner mate
Paddle like all crap.
and finally - add more salt to the water.

Sometimes a motor is just too small but a 8hpsghould push 2 folk in a small tinny if it isn't overweight..

[eyeskeenas]

Thanks guys, I will try lifting the Motor. it looks like its about 3/4 of an inch too low. the next step will be fdrop a few pounds. when i say there is only two in the boat. with me there are probably 3 in weight. failing that i might try a permatrim. Cheers

[Spaniard_King]

Drill the prop, start at 5mm holes

[eyeskeenas]

Drill the prop, start at 5mm holes

Drill the Prop??? Im not sure i know what you mean. are you taking the piss :) or is that something you can really do and how does this help. please tell me more.

[kizza1]

a foil and lifting the engine will give you the best results. also try tilting the engine in slightly to help you get on the plane.

if it is a 8hp jap (shift lever on the side) you can wind the throttle restrictor out slightly and i think you can change the throttle ramp with one off the 9.8 tohatsu to get a little bit more performance.

if it is a u.s 8hp (shift in the handle) you could get the components from a 15hp to beef it up.

[Spaniard_King]

Drill the Prop??? Im not sure i know what you mean. are you taking the piss :) or is that something you can really do and how does this help. please tell me more.

Have a look at the diagram
http://img.photobucket.com/albums/v235/perrycl/ventingprops.gif

You basically drill a hole behind each blade of the prop. This allows exhaust gasses to flow over the prop causing it to slip a little. The engine will rec more (the more a 2 stroke revs the more power it makes)

It may just do the trick

[eyeskeenas]

Have a look at the diagram
http://img.photobucket.com/albums/v235/perrycl/ventingprops.gif

You basically drill a hole behind each blade of the prop. This allows exhaust gasses to flow over the prop causing it to slip a little. The engine will rec more (the more a 2 stroke revs the more power it makes)


It may just do the trick

Ok now i understand, very cool idea. a mate did the same with a ride plate on a jetski to give it a bit more lift. cool stuff thanks for the tip.
cheers Eyeskeenas

[eyeskeenas]

a foil and lifting the engine will give you the best results. also try tilting the engine in slightly to help you get on the plane.

if it is a 8hp jap (shift lever on the side) you can wind the throttle restrictor out slightly and i think you can change the throttle ramp with one off the 9.8 tohatsu to get a little bit more performance.

if it is a u.s 8hp (shift in the handle) you could get the components from a 15hp to beef it up.

its a jap one with the shift on the side. maybe i will try that if lifting and foil doesnt work. its so close i recon if i lost 10kg it would be fine.