Mercury 150 4stoke

[GoneFishingLTN]

I have a mercury motor 150 4stoke and I've been driving it around 5 mph max and figured it's time to speed up and test it out.  I have a gauge that tells me to lower or higher my trim and my RPM  well it's always been stuck on the number two for my RPM but last time I took it out I got it up to about 7 mph and the RPM read perfect but after that it always wanted me to go higher than two where it was normally set every time before what could this mean?

 

also is there a RPM I should stay under while I'm picking up speed sorry if this seems confusing and I'm just not exactly sure what to do with the rpm reading. 

 

I'm sure this is really basic stuff I'm just trying to understand though since this is my first year with a bass boat

 

 

[J Francho]

What kind of boat is this?

[GoneFishingLTN]

2012 mercury

2005 Bass tracker tournament v18

[J Francho]

Trim the engine all the way in.

Put her in gear, and slowly push the throttle until you're on plane.

Trim out slightly until your bow is up out of the water, but not so much that it's porpoising.

 

That motor should have a rev limiter, so no worries of over throttling.

[GoneFishingLTN]

 When you say trim the motor all the way in does that mean past what the gauge says because it tells me to trim down to where it says OK ?

 

thank you for spending the time and helping me

[J Francho]

As far as it will go.  All the way down.  I wouldn't worry too much what the gauge says about trim.  It's a feel and ability thing.  Too much trim, and you feel it get squirrelly.  The RPM, so long as you don't go over 5500 rpm (that's just a guess on the redline for that motor), you should be fine. 

[WRB]

How long have you been idling around at 5 mph?

Re read your engine manual for break in rpm's, never heard of idling to break in any outboard engine. The usual practice is changing rpm's between 1,500  to 3,500 for a specified number of hours. 

Trim the engine down until it stops, run the engine up to 3,500 rpm's and slowly trim up the engine until you feel the bow raise and speed picking indicating you are on a plane....watch where you are going!

Tom

[Russ E]

All great information.

A couple other things to watch, if you have never got up to full speed is. When you are reaching max rpm, look back to make sure there is still a stream of water coming out of the engine. if you over trim on some boats, the water intake can come out of the water and start sucking air. Not good.

Also if you start throwing a rooster tail higher than the motor you are over trimmed.

[Russ E]

7 minutes ago, WRB said:

How long have you been idling around at 5 mph?

Re read your engine manual for break in rpm's, never heard of idling to break in any outboard engine. The usual practice is changing rpm's between 1,500  to 3,500 for a specified number of hours. 

Trim the engine down until it stops, run the engine up to 3,500 rpm's and slowly trim up the engine until you feel the bow raise and speed picking indicating you are on a plane....watch where you are going!

Tom

I just broke in a mercury pro xs 115 4 stroke. My manual said do not idle for long during breakin.

need to put a load on the motor.

I agree. Read the manual not all engines have the same breakin procedure.

[GoneFishingLTN]

30 minutes ago, Weedwhacker said:

I just broke in a mercury pro xs 115 4 stroke. My manual said do not idle for long during breakin.

need to put a load on the motor.

I agree. Read the manual not all engines have the same breakin procedure.

I bought the boat and motor used. The guy used it for tournament fishing it has 100 hours on it do I need to break it in after it has been winterized

[J Francho]

No, you do not.  You simply burn off the fogging oil (if it was fogged) and replace the spark plugs each spring.

[Russ E]

2 hours ago, GoneFishingLTN said:

I bought the boat and motor used. The guy used it for tournament fishing it has 100 hours on it do I need to break it in after it has been winterized

No. Sorry. I thought it was a new motor. after 10 hours it is good to go.

[iabass8]

Where exactly are you in IA? 

 

Assuming your trim gauge works, put the boat in gear and trim the motor down. The needle will go down and if you look back the motor will trim down, too. Gradually move the throttle forward. Your RPMS will increase and the bow of your boat will rise. Around 3000-3500 RPMS the bow will begin to drop. When the boat flattens out, trim the motor up. You'll feel the speed increase. 

[3crows]

It is a Mercury, put the hammer down on it and let the water fly. And fly it will. My family has run Mercs since the 60s on salt and freshwater boats. Some were Hades to start but once running, like the 150 Tower of Power, straight 6, shove the throttle down, there will be a whine and then Hades follows after. 

 

Five, (5), MPH? Huh?

 

What you do need to worry over is water, outboards require a regular water pump replacement, in fact, I bet your manual says annually. Watch your water pressure and the tattle tale stream, it should be solid. Running an engine will not hurt it as long as it has oil and plenty of water to cool it. It was built to run.

[GoneFishingLTN]

21 hours ago, iabass8 said:

Where exactly are you in IA? 

 

Assuming your trim gauge works, put the boat in gear and trim the motor down. The needle will go down and if you look back the motor will trim down, too. Gradually move the throttle forward. Your RPMS will increase and the bow of your boat will rise. Around 3000-3500 RPMS the bow will begin to drop. When the boat flattens out, trim the motor up. You'll feel the speed increase. 

Des Moines Ia.  

Thanks everyone for the replies. I don't know if I pay for a water pump replacemeant I pay for a full winterizeing every year is all I know. Water does shoot through it soomthly every time 

[J Francho]

You'd want to ask if it's included.  I winterize mine myself, and change out the impeller every other year.  It's a little tricky, but not hard, if you're somewhat mechanically inclined.

[slonezp]

5 hours ago, GoneFishingLTN said:

Des Moines Ia.  

Thanks everyone for the replies. I don't know if I pay for a water pump replacemeant I pay for a full winterizeing every year is all I know. Water does shoot through it soomthly every time 

A water pressure gauge would be the ideal tell tale of a bad water pump. If you run gin clear water, you could go years without replacement. If you are running shallow sandy or muddy water, it will be more often. Your mechanic can pull a computer report for you and might be able to tell if any deficiencies exist.

[3crows]

I generally change the impeller every other year though my manual say annual. 

[Hez]

On 9/18/2017 at 11:20 AM, GoneFishingLTN said:

2012 mercury

2005 Bass tracker tournament v18

 

I am thinking he is way past his break-in period

 

Edit: Sorry - I commented before I finished reading the thread 

[tcbass]

14 hours ago, 3crows said:

I generally change the impeller every other year though my manual say annual. One thing, actually two, do not start your engine out of the water, it will ruin the impeller, also, the second thing, tow your boat with the engine set in gear so the propeller does not free spin, that also ruins impellers. 

 

 

Never heard of trailering the boat with the engine in drive to stop the propeller from moving. Hmmm.....

[WRB]

So much mis information in this thread. We have gone from break in period to basic boat operation to water pumps changes and gages. It costs about $90 to have a professional change a water pump impeller, it's a little tricky aligning the drive shaft splines and re connecting everything properly unless you are a good mechanic.

Hire someone skilled at bass boating like a guide and have them teach you the basics of boat operation, cost you about $300 for a day on the water and well worth it from what I have read so far.

Your boat should have a water pressure gage and you should watch it to make sure the pressure stays between 10-15 PSIG after it has warmed up. The pee hole water only indicates the impeller is working, doesn't indicate the thermostat has opened allowing water to cool the power head.

Props spin when trailering doesn't hurt anything and is rare with heavy SST props with the engine trimmed up. 

Enjoy your new to you bass boat.

Tom

[slonezp]

9 hours ago, WRB said:

So much mis information in this thread. We have gone from break in period to basic boat operation to water pumps changes and gages. It costs about $90 to have a professional change a water pump impeller, it's a little tricky aligning the drive shaft splines and re connecting everything properly unless you are a good mechanic.

Hire someone skilled at bass boating like a guide and have them teach you the basics of boat operation, cost you about $300 for a day on the water and well worth it from what I have read so far.

Your boat should have a water pressure gage and you should watch it to make sure the pressure stays between 10-15 PSIG after it has warmed up. The pee hole water only indicates the impeller is working, doesn't indicate the thermostat has opened allowing water to cool the power head.

Props spin when trailering doesn't hurt anything and is rare with heavy SST props with the engine trimmed up. 

Enjoy your new to you bass boat.

Tom

The pee hole can also get clogged with debris and while no water will flow out of it, the engine can be working perfectly.

[WRB]

2 minutes ago, slonezp said:

The pee hole can also get clogged with debris and while no water will flow out of it, the engine can be working perfectly.

True! Looking for water being exhausted is another indicator, but a gage is the way to go.

Hopefuly the OP will learn more about his boat and motor.

Tom

[3crows]

13 hours ago, tcbass said:

 

The OP was not about engine break-in.