Ski Prop

[grima]

I have a 1970 Johnson 115 on a 14FT Swiftcraft Stiletto. The boat is used primarily for skiing. Can anyone tell me what the best size prop to use would be.<br /><br />Also, I've noticed that the spark plugs currently being used are NGK B9HS, the manufacturer recommends B7HS. Apparently the only difference is to do with how quickly the plugs dissipate heat. Is it worth changing to the recommended plugs? The ones in use are brand new.

 

[Dhadley]

Re: Ski Prop

What prop are you using now? Generally we use a small pitch for skiing to get them up quick.<br /><br />Be careful using anything other than a Champion plug in your motor. <br /><br />Good luck!

 

[grima]

Re: Ski Prop

Thanks for the prompt reply Dhadley. I'm not sure what the current prop pitch is. There are 3 numbers stamped onto the prop, but I can't recall them off the top of my head and I'm not at home at the moment.<br /><br />Does a small prop mean a quicker take off, or a higher top speed?<br /><br />Also, my Tacho isn't accurate. Can I replace it with a new one and use the same wiring?

 

[Dhadley]

Re: Ski Prop

Generally a lower pitch means a quicker holeshot and less top end. Check out your prop numbers and let us know. Your wiring harness should have universal wiring for the tach (tan = pulse, black = ground, purple = key on power, blue = light) and is critical in determing the correct prop. <br /><br />Good luck!

 

[grima]

Re: Ski Prop

Thanks Dhadley

 

[grima]

Re: Ski Prop

Dhadley, the only number I can find on the prop is 193.<br /><br />On a different note, I looked behind my current tacho and found the following:<br /><br />1 black wire, 1 grey wire, and four screws fitted close to each other with a yellow wire connected to two of the four screws. The yellow wire comes the the inside of the tacho, connects to the two screws and ends.<br /><br />I looked at buying a new tacho today ($130 AUD). Besides the wiring for a light, I found black, grey, and yellow/black wires. Not sure where the yellow/black wire would go as it didn't have the four close fitting screws.