1966 Chrysler 20 h.p. won't plane ? Prop problems ?

[stevecarr]

I have a pretty clean 1966 20 hp tiller outboard.<br />It has never been rebuilt and I was told it was taken care of ( bought from original owner ) and it looks like it . It came on a 14 ft fiberglass<br />v-hull , fairly wide and light weight boat . With <br />just me and less than 75 lbs of gear / battery / fuel the boat will not plane , not even close and runs less than 7 mph as a guesstimation . I changed the plugs and went back out the next day and found that if I move to the middle / front of <br />the boat it will plane and gain speed , guess around 15 - 18 mph , but as soon as I go back to the tiller , it losses plane . I wonder if changing the prop would help ? I think I read somewhere that a 2 blade was standard and mine has a 3 blade ? Wondering if someone changed it out or if a different prop would solve the problem ? I did remove the big pin and move the motor "tilt" up as far as it would go ? THanks in<br />advance . S C

 

[scotiany]

Re: 1966 Chrysler 20 h.p. won't plane ? Prop problems ?

I've got an old manual(not the Chrysler one) with that engine detailed. It shows two prop pics and both have a 3 bladed prop on it. I don't think moving your tilt adjust pin helped. Why don't you just put some weight up in front of boat.

 

[Terry H]

Re: 1966 Chrysler 20 h.p. won't plane ? Prop problems ?

20hp on a 14 ft f/g boat is not gonna be overly powerful. I would suggest you make sure the motor is running optimal, and keep the weight down and shifted forward...just a thought

 

[stevecarr]

Re: 1966 Chrysler 20 h.p. won't plane ? Prop problems ?

Or even better , take a friend ! ! This is the first "small" boat I've had , I moved next to a good sized river and bought this boat for that purpose . It may just seem slow to me being used to bigger bass boats ? but I do recall seeing other boats laid out like this one going up and down the lakes and rivers and they all seemed to have the "bow in the air" problem with just one person in them , I do have some room up front to put something , maybe my big old cooler filled with water ? I already have my 2 anchors up front , Thanks again for the post and help .

 

[rbruce63]

Re: 1966 Chrysler 20 h.p. won't plane ? Prop problems ?

Your Chrysler 20 came with a 14:21 gear ratio and an 8 1/2" X 8 1/2" pitch propeller three blade, now a days similar motors have a 2:1 reduction gear ratio that will allow the motor to make the propeller run slower but with the benefit of using a larger more efficient propeller. The displacement was not that big (19.96 cu.in) and puts it close to what a modern 15 HP would be. <br /><br />I would try raise the motor so that the anti-ventilation plate is at or 1" above the bottom of the hull. This will improve your pickup and your rpms. Please check the rpms at wide open throttle so that they are close to 5,500 rpms.

 

[norenebeaver]

Re: 1966 Chrysler 20 h.p. won't plane ? Prop problems ?

Hey rbruce - what is a anti-ventilation plate? I think is what you said - Thanks<br /><br />Norene

 

[stevecarr]

Re: 1966 Chrysler 20 h.p. won't plane ? Prop problems ?

Got a good sized hydrofoil on Ebay , new in the package for $12 shipped !! Going fishing Saturday morning to try it out , it couldn't hurt I guess . Also moved my 50# thrust minn kota to the front of the boat and put the big deep cycle battery in the middle of the boat . Hopefully this will solve the plane / speed problem . I guesstimate I lost around 50 lbs. in the extreme rear of the boat ( 14 ft.) by moving the stuff up towards the front , which would add another 50 up front , so in essence , that would be around 100 lbs difference . Will let ya know if this helped. Thanks again for all the help ! ( also picked up some "vintage" sparkplugs from ebay , NIB champions that the manual actual called for . <br /><br />Wetting a line is better than working !!

 

[stevecarr]

Re: 1966 Chrysler 20 h.p. won't plane ? Prop problems ?

The hydrofoil did the trick ! the weight moved forward helped too. At least now my old 20 hp will go faster than my 50# thrust trolling motor.<br />Steve