1973 mercury 1150 115 hp High rpms low speed.

[rhayes2849]

I have a 1973 mercury 1150 115 hp that gives me full rpms at full throttle but low speed. Some times it will slowly catch up and speed up. Please help.

 

[CV16]

Re: 1973 mercury 1150 115 hp High rpms low speed.

I would check the prop. The rubber hub could be bad and spinning. Put some fingernail polish on the prop and hub to see if the prop spins on the hub. If it does, bring it to a prop shop and have them fix it for you.

 

[Texasmark]

Re: 1973 mercury 1150 115 hp High rpms low speed.

I would check the prop. The rubber hub could be bad and spinning. Put some fingernail polish on the prop and hub to see if the prop spins on the hub. If it does, bring it to a prop shop and have them fix it for you.

+1. When you mark it the mark needs to extend from the splined brass out to the material from which the prop is made. Prop shops rehub as a regular service. However, if your prop is all dinged up, and an alum, you can get a new one on here for about $100 which wouldn't be too far from what you'd pay for a rehub. They are on sale and the Solace rubber hub props are about $40 off regular price.

HTH,
Mark

 

[rhayes2849]

Re: 1973 mercury 1150 115 hp High rpms low speed.

+1. When you mark it the mark needs to extend from the splined brass out to the material from which the prop is made. Prop shops rehub as a regular service. However, if your prop is all dinged up, and an alum, you can get a new one on here for about $100 which wouldn't be too far from what you'd pay for a rehub. They are on sale and the Solace rubber hub props are about $40 off regular price.

HTH,
Mark

Thanks for the help, can this test be done out of the water or should I be in the boat on the water? Its a SS prop.

 

[MH Hawker]

Re: 1973 mercury 1150 115 hp High rpms low speed.

Try marking it before you do any thing else.

 

[Texasmark]

Re: 1973 mercury 1150 115 hp High rpms low speed.

You mark it then go to the water. Firewall the throttle a couple of times while in the water after you get past the no wake zone. Try to get it on plane. A couple of minutes of that is all it takes.

Come back to the dock, put the boat on the trailer and take it home. When home, pull the prop nut and washer off and look at your marks. If misaligned, the prop hub is spun.

Mark