plane

[don1955]

I have a 55 hp johnson on a 16 ft tri haul, when i give full throttle and it starts to plane it sputters like the prop is out of the water, when i back off the throttle its fine but won't plane, do i need to adjust the bar on the motor to set the prop further down in the water, i had it on the 3 position,

 

[crxess]

Re: plane

What is the attitude of the hull? If it is nose high you may need to lower the motor angle or shift weight forward.

Sputtering at full throttle could also be fuel starvation or timing advance issue.

 

[don1955]

Re: plane

it's not really a sputter but more like hitting neutral for a second but it does it in and out for a few, but if you pull back a little on the rpm's it's ok but i wonder if there isnt enough water hitting the cavitation plate, and i am going to lower the motor more towards the stern to see if that helps, i'm sure i have enough motor to plane out the boat

 

[crxess]

Re: plane

Actually it sounds like you have a spun hub.

Remove the prop.
On the back side mark with a permanent marker from the Center to the edge.
Install the prop and take it for a run.
Once you have duplicated the problem, remove the prop and inspect the Mark you made. If it has separated into 2 lines the hub is slipping. If so, the prop will need to be rebuilt or replaced.

 

[a70eliminator]

Re: plane

I don't think his prop has a seperate hub, it's probably one with a sheer pin and spinner with a cotter pin? Anyhow I just went through raising my outboard motor one notch at a time till it started to slip then went back down a hole, all this was done with tilt pin all the way down, when the motor slipped raising the tilt did nothing but make it worse, I think you need to lower the motor, even if the cavitation plate is already below the keel.

 

[tashasdaddy]

Re: plane

even a shear pin prop has the double hub, it just used the (shear) drive pin, instead of splines. it sounds more like a clutch dog.

what 55hp is it? that would help a lot.

also you want the leg close to the hull for getting out of the hole, farther out for more speed, without trim n tilt, you have to find the happy place.

 

[a70eliminator]

Re: plane

even a shear pin prop has the double hub, it just used the (shear) drive pin, instead of splines. it sounds more like a clutch dog.

what 55hp is it? that would help a lot.

also you want the leg close to the hull for getting out of the hole, farther out for more speed, without trim n tilt, you have to find the happy place.

Oh thanks I did not know that about the hub, now I'm going to look at my props a little closer, I though the sheer pin ones with no spline were solid hmmm I still can learn the most basic stuff....!

 

[don1955]

Re: plane

It's a 1976 55 hp johnson ,on my 71 fiberglass trihaul, do you think it's enough motor to plane this boat, the boat weighs between 500 to 600lbs?

 

[tashasdaddy]

Re: plane

it is enough if you have a healthy motor and boat. a boat that age could be holding and extra 500 LBs in water logged foam.

would check compression spark and fuel delivery on the motor. see the top secret file.