Fixed my prop problem now one more problem left

[Claude75]

Thanks to everyone who helped me with my prop problem. Just to recap I had a 22" pitch on a 15 foot runabout with a 75HP. I went down to a 17 pitch and got my RPMS up to 5500 RPM recommended for the 1986 Mercury 75HP. Just one more question though. My boat rides really high when trying to plane and there is a spot I would say 3800-4500 RPM where it seems my 13.25x17 SS prop is not catching the water it seems to riding the bow high and having a proplem planing with 5 people on board(I know thats high). Anyhow do you think putting a dolphin tail(those two pieces of plastic that go on the lower drive) would help. Perhaps trim tabs are the answer?<br /><br />Thanks, <br /><br />Claude

 

[robnik1]

Re: Fixed my prop problem now one more problem left

Hello <br /> Are you able to adjust the trim?

 

[LubeDude]

Re: Fixed my prop problem now one more problem left

Make sure your trimm pin is in one of the lowest holes towards the transom. Start all the way down, if you have what is known as bow steer, (you will know it if you have it), raise it a hole.

 

[roscoe]

Re: Fixed my prop problem now one more problem left

Doelfin may help.<br />Do you have the motor trimmed in (down) all the way when trying to get up on plane?<br /><br />Is the anti-cavitation plate of the motor approx lined up with the bottom of the hull?<br /><br /> See this picture!!

 

[Claude75]

Re: Fixed my prop problem now one more problem left

I am able to adjust the trim. It seems that the trim is all the way down. When I looked at the picture I would say the cavitation plate is approx 1 inch above the bottom of the hull. I should probably mention when there is only two or so people on board it hops right up on plane with no problem, but there is still 3800-4500 jump of RPMS very quickly. <br /><br />Thanks, <br /><br />Claude

 

[Claude75]

Re: Fixed my prop problem now one more problem left

Roscoe: <br /><br />One more thing. I went to check the anti-cavitation plate again, and it is up one inch put it is not parrell to the bottom of the hull. It is up one inch and then by the time it gets to the hull it is even again. I also notice there are five or six holes were a bolt goes through to stop the tilt from going down further. The first hole is empty the second hole has a bolt going through it(this is the second hole from the hull that is). Any thoughts. Perhaps if I remove the second screw and put it into the first one I will get the anti-caviation plate to be parrarell to the bottom of the hull?<br /><br />Thanks, <br /><br />Claude

 

[LubeDude]

Re: Fixed my prop problem now one more problem left

If this engine has power trim, remove the bolt and leave it out so you can trim under all the way. If no power trim, buy the right pin and put it in the bottom holes. If you do not have a stainless prop, you may not have enough cup to keep the prop hooked up.