Tracker v16 - 90hp mercury 2 stroke - slow top speed at 5800 rpms

timmyboy188

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Hello all. I've done some searching around, and I'm thinking I've come to the conclusion I want to upgrade to a 21 pitch SS laser II prop. I'm currently running 30 mph WOT at 5800rpms, with an aluminum 19 pitch solas prop, and my holeshot is very good! Trim is all the way down, and cavitation plate lines up with bottom of hull. Motor has been recently tuned and is running really well.

Can someone maybe give a guesstimate on top speeds going to a 21 pitch, or even 22 pitch?

I stay at 30 mph whether I am by myself for if I have another in the boat.

Thanks in advance!

Tim
 

Mi duckdown

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Re: Tracker v16 - 90hp mercury 2 stroke - slow top speed at 5800 rpms

Why mess with success? What is the max RPM for that Motor? assuming you tach is correct.?? is that GPS speed?
 
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timmyboy188

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Re: Tracker v16 - 90hp mercury 2 stroke - slow top speed at 5800 rpms

Well, I've been told max rpm is in the 5800 range. It's an 06 mercury 2 stroke.

I'd love to be closer to 40 mph, so I'm hoping maybe I can get close to it with a higher pitch.

Thanks
 

jestor68

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Re: Tracker v16 - 90hp mercury 2 stroke - slow top speed at 5800 rpms

Those numbers come out to a 33% slip; not likely for that boat type.

An 11% slip shows less than 5000 rpm.

Are you sure your rpm/speed are accurate? Your gear ratio should about 2.33.

You might do a quick check for hub slippage.

RPM range should be 5000-5750.

Using 11% slip and your numbers; it shows a theoretical 45 mph and actual 40 mph.

What Solas prop do you have; Amita or Rubex? If a Rubex, did you torque the prop nut to 60 lb ft when you initially installed it? It takes that much torque to seat the hub properly.
 
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timmyboy188

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Re: Tracker v16 - 90hp mercury 2 stroke - slow top speed at 5800 rpms

I don't think I've got slippage, tracker just did a big inspection on it and didn't mention any kind of slippage.

So with my low rpm range being 5000, couldn't i go up to a 22 pitch ss, and my rpm would drop to about 5200?
 

jestor68

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Re: Tracker v16 - 90hp mercury 2 stroke - slow top speed at 5800 rpms

If you visit the Mercury prop selector and input your boat's data; it'll tell you that a 19 pitch prop should do about 5375 rpm @ 36.6 mph, which works out to a 13% slip; within the range(10-13%) considered normal for that type boat.

Either your prop's hub is slipping (not likely to be found on any kind of "inspection") or the tach is wrong(not unusual).
 
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timmyboy188

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Re: Tracker v16 - 90hp mercury 2 stroke - slow top speed at 5800 rpms

What's typically required to repair slippage? Is that basically just a new prop?
 

Texasmark

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Re: Tracker v16 - 90hp mercury 2 stroke - slow top speed at 5800 rpms

Look at my Avatar. 17.5' River trail, alum BB, '02 90 Merc, Ballistic 24P SS with all the toys. Runs 50 GPS on a cool day at 5700-5800....... Engine rated for 5500 max but have had it to 7000 once when fooling with the timing......still running strong.

Mark
 

jestor68

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Re: Tracker v16 - 90hp mercury 2 stroke - slow top speed at 5800 rpms

Look at my Avatar. 17.5' River trail, alum BB, '02 90 Merc, Ballistic 24P SS with all the toys. Runs 50 GPS on a cool day at 5700-5800....... Engine rated for 5500 max but have had it to 7000 once when fooling with the timing......still running strong.

Mark

Does your boat employ a 20 degree dead rise V hull? I doubt it.

Tracker estimates the speed with a Merc 90 at 37-40 mph.

Mercury web site has a test of a Tracker Pro Guide V-175 SC/Merc 90; very similar to your boat.

Using a Black Max 13 X 19, it shows 38.5 @ 5500 rpm carrying a light load.

Your boat should perform in a similar fashion, since the weights are very close and your boat is 11" shorter.
 
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Texasmark

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Re: Tracker v16 - 90hp mercury 2 stroke - slow top speed at 5800 rpms

Does your boat employ a 20 degree dead rise V hull? I doubt it.

Not familiar with the Tracker hull. Here's mine. Not much of it in the water at WOT as the Avatar wake shows. For another $500 I could up the pitch a couple of inches, pull my rpms down into the recommended range and get a couple more mph.
 

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jestor68

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Re: Tracker v16 - 90hp mercury 2 stroke - slow top speed at 5800 rpms

Not familiar with the Tracker hull. Here's mine. Not much of it in the water at WOT as the Avatar wake shows. For another $500 I could up the pitch a couple of inches, pull my rpms down into the recommended range and get a couple more mph.

Yours is a Mod V; his is a deep V.

I agree that you are not familiar with Tracker deep V hulls.
 

Texasmark

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Re: Tracker v16 - 90hp mercury 2 stroke - slow top speed at 5800 rpms

Yours is a Mod V; his is a deep V.

I agree that you are not familiar with Tracker deep V hulls.

Sorry, mine has a modified pad! You are not familiar with mine even with a picture in front of you!
 

jestor68

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Re: Tracker v16 - 90hp mercury 2 stroke - slow top speed at 5800 rpms

Sorry, mine has a modified pad! You are not familiar with mine even with a picture in front of you!

I doubt few people have ever heard of your boat.

And what does your obscure (brand) of boat have to do with this topic?

He has been provided with two solid references as to what to expect from his Tracker deep V hull boat.

You coming into the topic bragging about how fast your bass boat(?) will go adds nothing to the discussion.

By the by; the boat in my avatar does 96.4 mph any day, not that it has anything to do with the topic.

A mere 50 mph is ho hum these days.
 
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timmyboy188

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Re: Tracker v16 - 90hp mercury 2 stroke - slow top speed at 5800 rpms

Thanks for all the help guys. I'm going to the techs that sold me the boat to get my title, and I'm going to talk to them about checking the hub and see if it possibly needs a new hub kit.

Just a thought, would I get better speeds with the motor trimmed up a bit, since it is a deep V, rather than the trim all the way down at WOT?

Tim
 

jestor68

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Re: Tracker v16 - 90hp mercury 2 stroke - slow top speed at 5800 rpms

Thanks for all the help guys. I'm going to the techs that sold me the boat to get my title, and I'm going to talk to them about checking the hub and see if it possibly needs a new hub kit.

Just a thought, would I get better speeds with the motor trimmed up a bit, since it is a deep V, rather than the trim all the way down at WOT?

Tim

Yes; once up on plane, you want to trim up/out until you hit that point where you begin to ventilate the prop(motor revs higher and the prop loses bite); then bump it down til the prop regains grip. That is your optimum trim angle for most top speed, but you may not need that much trim out at cruising speeds.

The Tracker deep V hull tends to ride with little bow rise, but you will see an increase in speed with some positive trim. If you've been running with it trimmed all the way down, that would definitely cost you several mph.

Have the shop verify your tach, since you shouldn't get that much rpm trimmed all the way down.
 
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Texasmark

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Re: Tracker v16 - 90hp mercury 2 stroke - slow top speed at 5800 rpms

I doubt few people have ever heard of your boat.

And what does your obscure (brand) of boat have to do with this topic?

He has been provided with two solid references as to what to expect from his Tracker deep V hull boat.

You coming into the topic bragging about how fast your bass boat(?) will go adds nothing to the discussion.

By the by; the boat in my avatar does 96.4 mph any day, not that it has anything to do with the topic.

A mere 50 mph is ho hum these days.

Wake in your avatar doesn't look like any 96.4; more like 35 or 40. Got any pics?
 

timmyboy188

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Re: Tracker v16 - 90hp mercury 2 stroke - slow top speed at 5800 rpms

Well that was the issue, having the trim all the way down. I'm so used to flat bottom boats, I didn't think about the deep v hull causing drag while at full trim, played with it a bit, got it to a sweet spot, and I got up to about 37 MPH and 5600rpm. The boat handles MUCH better when the trim is right too. Thanks for all the help guys!

Tim
 

Fish'n Lewi

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Sep 29, 2009
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Re: Tracker v16 - 90hp mercury 2 stroke - slow top speed at 5800 rpms

Well, I'm glad to hear you have it figured out. When I first read it I was thinking something wasn't right also. I have an 06 Tracker V16 with a 75 HP Merc 4 stroke 17p prop and I will run 40mph even all day.


Lewi
 
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