need to plane out. 1978 evinrude 115

anderso8623

Petty Officer 1st Class
Joined
May 25, 2012
Messages
388
Hi all, I have a 1978, 115hp evinrude. It is on a 1987 17ft mako standard, that may or may not be over weight from water as I sit lower the the spec'ed 7 inch draft. More like 14 inches sit in the water base on the stained water line to the bottom of the V on my transom. I am running 4000 RPM at WOT on a calm day. A strong current and I'm at 3500 WOT. It takes me some time to get there, sometims a few minutes, and needs a few taps on the choke for a little extra boost. Until i hit about 18 mph and about 3500 rpm, i will not plane. I am running a 14 inch, 17 pitch aluminum prop, three blade. While at 4000 RPM I am hitting about 22. Should I drop to a 15 pitch?
 

anderso8623

Petty Officer 1st Class
Joined
May 25, 2012
Messages
388
Almost no fuel and myself onboard, maybe 225 lbs between gas and myself and gear
 

Bondo

Moderator
Staff member
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Apr 17, 2002
Messages
70,470
Ayuh,..... If ya get a boost of power by chokin' the motor, I'd think it's down on power, from a fuel restriction,.....

Start with a Tune Up,...
 

Bob_VT

Moderator & Unofficial iBoats Historian
Staff member
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May 19, 2001
Messages
26,019
Wait...... check the items in your other post FIRST. The question you posted in the motor section.........Take it one step at a time. Do not make any prop changes yet.
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
I agree with the engine checklup. When I accidently hit the choke on my similar outboard at speed it slows down until I realize my elbow is leaning on the choke button :)
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
I agree it would seem that if the choke improves power it may be starving a little for fuel.
You want to be sure it's not running lean as this can cause major issues over time.
 

anderso8623

Petty Officer 1st Class
Joined
May 25, 2012
Messages
388
It ended up being the spark advancement linkage. The ball and socket connection had been falling off due to wear. Replaced and it planes out just fine. I'm hitting about 5200 WOT and about 35 MPH in about 1 ft chop, I could drop to a 15 pitch but I won't worry about this till next season. Does the 35 mph sound right for this rig?
 

SkiDad

Lieutenant Commander
Joined
Jul 18, 2010
Messages
1,518
that sounds about right for a 1400 lb hull - you might be able to get a little closer to 40 with the right tweaks. I wonder if your timing is correct now that you changed that piece (well at least on my engine that affects that but might be different on an Evinrude) - it might be off a few degrees and worth checking.
 
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