1968 6hp prop

[kevkc123]

Ive got a 6hp chrysler I believe is a 1968( don't know model off hand). My question is what prop should be on that. it has a 2 blade on now but it feels like the motor is working harder than it should. I mean at wot it seems like it should be moving my 12ft. rowboat better. Maybe a 3 blade was stock or would work better? Or maybe different 2 blade? If different prop desired, where is the best(cheapest) place to find one? <br /><br />Thanks!

 

[steelespike]

Re: 1968 6hp prop

More than likely your prop is correct.Check your<br />compression should be around 100 lbs.Be sure the throttle is opening all the way.Be sure it is running on both cylinders.To keep it<br />simple the number of blades does not directly affect prop performance.Diameter and pitch are the primary performance factors.More pitch <br />(higher number)less power more top speed lower<br />pitch (lower number)more power less top speed.<br /> But your motor is so little if you put more pitch on it you would lose speed.You could try<br />less pitch but my thoughts are it is right on.<br />On your little boat weight distribution and<br />motor trim are are critical It will be hard for it<br />plane with the tank in the back and if you weigh<br /> much more than 100 lbs.You should trim the motor<br />in(prop closer to the boat).You may need to add a<br />tiller extension so you can sit forward more.With<br />careful weight distribution And a light load your<br />motor should plane but barely,maybe 15 to 18 mph.

 

[steelespike]

Re: 1968 6hp prop

Forgot to add your motor should have a high speed<br />mixture adj which you need to adjust to the best performance.

 

[steelespike]

Re: 1968 6hp prop

Forgot to add your motor should have a high speed<br />mixture adj which you need to adjust to the best performance.

 

[kevkc123]

Re: 1968 6hp prop

Spike, I keep the tank in the front and run fuel lines back. The boat planes out fine it just feels like the prop is pushing water like i'm spinning a popsicle stick. You're right about the pitch, there isn't much to it and the boat gets moving real quick. Maybe i'm unrealistic about my expectations, but i feel it should move better at WOT. Also, where would i find that mixture screw(usually). <br />I appreciate the help!

 

[WhiteHorse]

Re: 1968 6hp prop

mixture screw is on the carb in that model, unless yours was retro-fitted and it's in the front of the motor in the base pan cowling. That motor came from the factory with a 2-blade prop.

 

[steelespike]

Re: 1968 6hp prop

I did a little research your carb has a fixed jet.<br /> Sound like the motor runs great and has a good hole shot.Maybe you could play a little.<br />The motor developes 6 hp at 5,000 rpm.<br /> You could get a tinytach (they have a web site)<br /> Check the rpm Im not sure of the max reccomended<br />but obviously around 5,000.Finding a prop could be a little difficult but try Fairwinds Marina or<br />maybe Twin cities outboards www.tcoutboard.com.<br /> There could be diameter and pitch numbers on your prop.A prop shop may be able to tell you if it is a standard number.