boat wont plane out

[mullo96]

have a 16 ft bass boat with 85 johnson on it it is a 74 model boat and motor 120lb compression in all cylinders but one and it has 115lb, motor idles good and reves up good all linkages working properly all new plugs good fire on all cylinders boat just wont build up enough speed to plane out runs about 1/3 throttle under load.<br /> mullo96

 

[MGuckin]

Re: boat wont plane out

What is the maximum rpm that you achieve? Have you tried trim and tilt adjustments? Do you know what size prop you have? Does the bow hang or plow?

 

[Dhadley]

Re: boat wont plane out

We need more info. Are the carbs clean? What plugs are you using? What prop are you using? What fuel and how old (specifically -- not just "good")? What Oil? What ratio? What load? What timing?<br /><br />let us know!

 

[JB]

Re: boat wont plane out

Hey, Mullo.<br /><br />While you are at it, did the boat ever plane to your satisfaction? What happens if you pump the primer bulb? <br /><br />Don't let a smooth idle or revving with no load fool you into thinking that all cylinders are making power. Check that all four are actually making power by disabling one cylinder at a time by pulling or shorting out each spark plug.<br /><br />Let us know what you find.

 

[mullo96]

Re: boat wont plane out

thanks guys for the replys cleaned carbs today ran a lot better for about five minutes still wouldnt plane completely out unless someone sat on the front of boat. The plugs are what are called for and are new ,the prop is a 13 3/8 x 17 degree pitch. Fuel is 16 oz to 6 gallons of gas and is fresh fuel just mixed and put in. <br /> mullo96

 

[IndySpecialty]

Re: boat wont plane out

That motor should be propped so it will turn 5500rpm's fully loaded with all the gear & your normal amount of people in it, then when its empty & low on fuel just throttle back & don't over rev.it. " IT NEEDS A 15 PITCH PROP "<br /><br />Good Luck!!!<br /><br />indydan

 

[mullo96]

Re: boat wont plane out

Thanks again not sure but belive this is the prop that came with this boat and motor ,noticed wax had run out of stator but it is still making fire had to replace the rectifer on it and the tac read 5000 rpm when it was running for the first few minutes then fell back to 1500 to 2000 at full throttle Thanks mullo96

 

[bmurray]

Re: boat wont plane out

Once everything is running good, you could try a Hydrofoil. They do help with getting your boat on plane. The SE Sport has less drag for got top speed. Good luck