15 hp Johnson no power

J

Johnson209

Seaman
Joined
Oct 25, 2012
Messages
72
Re: 15 hp Johnson no power

OptsyEagle said:
I can't say what the other numbers that you listed indicate. Probably a batch number or something like that. The UL81C are numbers where each letter and number has specific meaning. I forget which are which but the 81 indicates the heat range, the others help sort out thread size, whether it is a resistor plug or not, the thread reach and sometimes even the gap and electrode type. Those are the numbers/letters the designer will need to look at when figuring out the best spark plug for a given motor.
Click to expand...

Thks for clarifying... Now I understand
:)
 
J

Johnson209

Seaman
Joined
Oct 25, 2012
Messages
72
Re: 15 hp Johnson no power

Ok, took the boat out today. The motor seems a bit better then before. I got the gps reading at 13 to 14 mph wot with three person approximately 450 pound on board. Does this seem about right with my 15 hp or should i be going faster?

Thks
 
kfa4303

kfa4303

Banned
Joined
Sep 17, 2010
Messages
6,094
Re: 15 hp Johnson no power

That sounds about right, considering the load. You might pick up a few mph with only one or two people in the boat.
 
O

OptsyEagle

Lieutenant
Joined
Sep 13, 2006
Messages
1,365
Re: 15 hp Johnson no power

Also, try adjusting your trim rod. I usually put mine in position 2 (counting from the transom out) when I am alone and position 3 when I have a few people in the boat with me. It really helps get the boat on plane and allow for more speed. If it is in position 1, the bow plows through the water, slowing me down considerably and position 4 or 5 (and 3 when alone) will have my nose bobbing up and down when at higher throttle speeds. Anyway, play with it and see what works best for your boat.

The motor sounded fine in the video. Good job.
 
J

Johnson209

Seaman
Joined
Oct 25, 2012
Messages
72
Re: 15 hp Johnson no power

OptsyEagle said:
Also, try adjusting your trim rod. I usually put mine in position 2 (counting from the transom out) when I am alone and position 3 when I have a few people in the boat with me. It really helps get the boat on plane and allow for more speed. If it is in position 1, the bow plows through the water, slowing me down considerably and position 4 or 5 (and 3 when alone) will have my nose bobbing up and down when at higher throttle speeds. Anyway, play with it and see what works best for your boat.

The motor sounded fine in the video. Good job.
Click to expand...

Thks OpstyEagle u been really helpful.
I wouldn't been able to do this without your help. And to all others who tired helping me too thanks also. I will try playing with Transom. Now that the engines seems to run fine. The next step is buying a ss prop and a higher pitch. I'm at a ten right now with stock prop. What do u think or should I just leave it as it is. It's still kinda of slow for me considering I had a 25 hp on my boat before.
 
kbait

kbait

Commander
Joined
Nov 13, 2007
Messages
2,480
Re: 15 hp Johnson no power

Higher pitched prop will give less RPM's at full throttle, so you're not in the motors max hp range, so you'll go slower.
 
J

Johnson209

Seaman
Joined
Oct 25, 2012
Messages
72
Re: 15 hp Johnson no power

kbait said:
Higher pitched prop will give less RPM's at full throttle, so you're not in the motors max hp range, so you'll go slower.
Click to expand...

I always thought the lower pitch you go, the boat will plane quicker but is slower at higher rpm while higher prop is slow getting up on plane but will give you more speed.

In that case I should be dropping a pitch down because I want all the speed I can ease out of this motor:)
Thanks
 
O

oldman570

Lieutenant Commander
Joined
Mar 25, 2011
Messages
1,615
Re: 15 hp Johnson no power

The 10 pitch should be what is best for overall performance for that size motor. Several other factors figure into just how the motor performs, weight in the boat, placement of that weight, height of the motor in relation to the bottom of the boat, and pin setting on the motor. Even 50# of that weight in the wrong place will slow the boat down. This and the fact that the motor is of less HP than one is use to should be thought of. tHE 15hpmotor is a very fine motor but it will not replace the performance of a larger motor. I have found that a stainless prop is fine for motors that are run in waters with few chances of hitting anything but will cause more damage if used in shallow waters of rivers as the current changes the deepth of the water quite often. JMO
Oldman570
 
J

Johnson209

Seaman
Joined
Oct 25, 2012
Messages
72
Re: 15 hp Johnson no power

oldman570 said:
The 10 pitch should be what is best for overall performance for that size motor. Several other factors figure into just how the motor performs, weight in the boat, placement of that weight, height of the motor in relation to the bottom of the boat, and pin setting on the motor. Even 50# of that weight in the wrong place will slow the boat down. This and the fact that the motor is of less HP than one is use to should be thought of. tHE 15hpmotor is a very fine motor but it will not replace the performance of a larger motor. I have found that a stainless prop is fine for motors that are run in waters with few chances of hitting anything but will cause more damage if used in shallow waters of rivers as the current changes the deepth of the water quite often. JMO
Oldman570
Click to expand...

Thks oldma57 I'll take that into consideration.
 
J

Johnson209

Seaman
Joined
Oct 25, 2012
Messages
72
Re: 15 hp Johnson no power

OptsyEagle said:
Also, try adjusting your trim rod. I usually put mine in position 2 (counting from the transom out) when I am alone and position 3 when I have a few people in the boat with me. It really helps get the boat on plane and allow for more speed. If it is in position 1, the bow plows through the water, slowing me down considerably and position 4 or 5 (and 3 when alone) will have my nose bobbing up and down when at higher throttle speeds. Anyway, play with it and see what works best for your boat.

The motor sounded fine in the video. Good job.
Click to expand...

Hey OpstyEagle, I finally had the chance to test the motor by myself n this motor fly's.. I'm hitting 20 to 21 mph with just me on a 14 foot valco. I had the Trim rod set at number 4...

The nose seems to plane way to high and seems dangerous but it's perfect with three person on board. I'm hitting 15 with three people and 20 by myself. I'm still thinking bout going down a pitch also, what do you think ? Or do you think this is the max I"ll probably get from this motor.

Thanks for all your help
 
O

OptsyEagle

Lieutenant
Joined
Sep 13, 2006
Messages
1,365
Re: 15 hp Johnson no power

I cannot comment on the prop pitch and what affect a change might produce. The position 4 on the trim is certainly too much when you ride alone. I think I use #2 for that and #3 with others. In my boat, when alone with trim on #3, the bow will just bounce up and down when at WOT and that certainly doesn't help things.

I would say 20mph is probably giving you everything that set up can put out.
 
O

oldman570

Lieutenant Commander
Joined
Mar 25, 2011
Messages
1,615
Re: 15 hp Johnson no power

OptsyEagle is right and the danger of a gust of wind catching the front of the boat can cause it to flip over or throw a single operator out of the boat. Best to set the trim rod down for the load that is going to be in the boat beforehand at the ramp or leaving the dock. The extra load and placement in the boat will dictate just where the trim rod needs to be for the best performace and safe operation of all involved. The WOT speed is great for the motor as I have a simaler unit with a 20hp and it runs 21MPH by GPS.
Enjoy and be SAFE,
Oldman570
 
J

Johnson209

Seaman
Joined
Oct 25, 2012
Messages
72
Re: 15 hp Johnson no power

oldman570 said:
OptsyEagle is right and the danger of a gust of wind catching the front of the boat can cause it to flip over or throw a single operator out of the boat. Best to set the trim rod down for the load that is going to be in the boat beforehand at the ramp or leaving the dock. The extra load and placement in the boat will dictate just where the trim rod needs to be for the best performace and safe operation of all involved. The WOT speed is great for the motor as I have a simaler unit with a 20hp and it runs 21MPH by GPS.
Enjoy and be SAFE,
Oldman570
Click to expand...

Thks a lot guys... I really apreciate all the nice info u guys are giving me. It really help A lot. I be sure to take it with me when boating. Thanks


Happy boating to you all and be safe out there also :)
 
You must log in or register to reply here.
Top