Tracker V16 motor height

[boatlose]

Hey all,

I picked up a very used 2004 Tracker pro guide v16 WT with a merc 40hp 4 stroke 3 cylinder EFI.

Not that I was expecting to win any races, but this thing is a dog. Can barely hit 20mph in perfect conditions.

Anyone have a similar setup who can throw some knowledge my way? It gets to about 4800 of its 6000 max rpm. 10 3/8” x 11p 3-blade prop. Compression numbers looked great and doesn’t seem to misfire or anything. It just seems like a heavy boat for this motor.

The previous owner has the motor mounted on the highest hole, the anti-vent plate is about even with the lowest part of the hull.

Think it’s worth raising up 1-2 holes? Or do I have bigger power problems?

 

[flatheadsteve]

I would re prop and try to get those 1200rpm back before changing outboard height. You need a much smaller prop i would try a 7 or 8 pitch...

 

[LDUBS]

I saw a Mercury 40 HP four stroke performance test on a Bayliner with a 1,500# dry boat weight. Speed was 27 at 6,000 rpm. They were turning an 11 pitch Black Max prop. That boat is a lot heavier, but yours is still 1,000# before the motor and gear. I think you should do better than 20 mph. How much better I don't know. Hopefully someone with a similar set up will chime in.

I think @flatheadsteve has it right to try with a smaller pitch prop. You might want to run through Mercury's online prop selector tool (I show a 12.25 x 9p, but made some assumptions).

 

[flatheadsteve]

Not sure the age of your tracker but sometimes the flotation foam installed In tin boats will absorb water over the years and add a lot of weight. You may not have this problem but it's worth a check.

 

[MrGiggles]

Assuming that has a 90hp max like the current V16 WT models, it'll be hard to get much out of it at less than half of max HP. A little less prop might help.

 

[airshot]

Go weigh your boat and see if you have excess water. I have a 16' Sylvan side console that weighs 1000 lbs with 4 batteries and gear. Mine will hit 31 mph with me in it when trimmed out !! Mine is a two stroke 4 cylinder 40 hp Merc.That heavy 4 stroke and excess water might be slowing you down. Gotta get that rpm up to max...good luck

 

[boatlose]

Thanks for your replies, everyone. Will update thread eventually once I get to the bottom of it.

I was considering re-propping also, just seems like such a small pitch prop for what I have. But then again, the RPM doesn't lie. I'll probably have a marine mechanic take a look at it too, see if it's missing and I'm just not noticing it.

The max on the plate is 60HP, but apparently Tracker is well-known for under-rating their hulls in the past. A while back I calculated the max motor size with the USCG formula and it was north of 100hp.

 

[airshot]

Can't believe your prop pitch is the real issue, on my boat (described in earlier post) runs a 10.5x 13P. Prop at 5600 rpm and 31 mph by gps. Can't believe you need to drop down to a 9" pitch !!

 

[LDUBS]

Can't believe your prop pitch is the real issue, on my boat (described in earlier post) runs a 10.5x 13P. Prop at 5600 rpm and 31 mph by gps. Can't believe you need to drop down to a 9" pitch !!

Yeah that is a very good point. And an OEM prop is likely in the $150 range so a costly experiment for sure. Then again, involving a qualified Merc mechanic will likely cost that or more. Tough call.

Reading your post does make me rethink this a little. This is a 10 year old boat. Assuming the 11p prop has been there all along, it is hard to think no one addressed this before if it was a simple prop size issue. That would support something else going on.

 

[boatlose]

I'm going to scuttle it if the flotation is waterlogged

 

[flatheadsteve]

I looked up specs on a pro guide v16 wt × 1200lbs dry with a 7.5ft beam and rated for a 90 the 60 is said to push it 28-30. That's for a new one idk how different you're may be. Big boat for a 16 footer . Solas amita makes a good prop for less than factory.

 

[FuzzyGrub]

1200 rpm shy of your recommended WOT rpm, tells me there is another issue. I wouldn't waste money on a low-pitched prop. It will also go slower than you are now.

I'd check the foam first, but sometimes that is hard to access. Can scale the boat, launch, and rescale the trailer. Just imagine the people at the transfer station, when they think you are about to scrap the boat.

If it is not an overweight condition, then I'd see what the Merc mechanic has to say. It might be running in a "protect" mode, but whould have expected some kind of engine beeps.

 

[LDUBS]

1200 rpm shy of your recommended WOT rpm, tells me there is another issue. I wouldn't waste money on a low-pitched prop. It will also go slower than you are now.

I'd check the foam first, but sometimes that is hard to access. Can scale the boat, launch, and rescale the trailer. Just imagine the people at the transfer station, when they think you are about to scrap the boat.

If it is not an overweight condition, then I'd see what the Merc mechanic has to say. It might be running in a "protect" mode, but whould have expected some kind of engine beeps.

"It will also go slower than you are now."

I'm not following this. I mean it could, but why is it a sure thing?

 

[FuzzyGrub]

"It will also go slower than you are now."

I'm not following this. I mean it could, but why is it a sure thing?

I wouldn't say absolute, but very highly likely. The general rule with dropping pitch, you get on plane quicker, but lose speed on the top end. In this case, you can assume he will gain 150-200 rpms per 1" of pitch decrease.
Use Mercs prop slip calculator: Merc Prop Slip Calc

Put in 11P, 2 Ratio (per a google search), 4800 RPMs, 20MPH, and calculate slip = 20%, which is high

Change to a 7P, 2 Ratio, 5600 RPM, 20% slip, and calculate Speed = 15 mph

If you halve the slip to 10%, speed is 17 Mph, if you take it to 5%, = 18mph. 0 slip, which is impossible is 19 mph.

Normal slip is 5-10%

Keep in mind the calculators are not exact and make assuptions like the prop change is of same blade/style.


A 7P is probably the smallest you can get for his motor. That would be for an extremely heavy boat or a non-planing hull.

 

[LDUBS]

I wouldn't say absolute, but very highly likely. The general rule with dropping pitch, you get on plane quicker, but lose speed on the top end. In this case, you can assume he will gain 150-200 rpms per 1" of pitch decrease.
Use Mercs prop slip calculator: Merc Prop Slip Calc

Put in 11P, 2 Ratio (per a google search), 4800 RPMs, 20MPH, and calculate slip = 20%, which is high

Change to a 7P, 2 Ratio, 5600 RPM, 20% slip, and calculate Speed = 15 mph

If you halve the slip to 10%, speed is 17 Mph, if you take it to 5%, = 18mph. 0 slip, which is impossible is 19 mph.

Normal slip is 5-10%

Keep in mind the calculators are not exact and make assuptions like the prop change is of same blade/style.


A 7P is probably the smallest you can get for his motor. That would be for an extremely heavy boat or a non-planing hull.

Thanks @FuzzyGrub. I can understand this. The Merc Prop Slip Calculator is pretty cool. I played around with it a little. Going to a 9p would increase wot rpms, but no speed gain.

 

[boatlose]

Also keep in mind that going down a bit in pitch could get you in a better spot in your engine's powerband, where you get the best of both worlds. I assume.

 

[LDUBS]

Also keep in mind that going down a bit in pitch could get you in a better spot in your engine's powerband, where you get the best of both worlds. I assume.

I would assume the same thing. Well, if you do try a different prop and it works better, great. If it doesn't you have a spare prop.

 

[Still Afloat]

Personally, I’d start with fresh spark plugs, a new fuel filter and fresh fuel before buying props. Then I wouldn’t get carried away, maybe try 10” or 9” prop.

Also, weighing the boat is good advice and it the cost is minimal.

 

[Skunked again]

Do you have a local mill/grain station? If so, call them, see what the charge is to weigh. Our local one doesn’t charge, as long as two things - 1 you don’t need a ticket (pull on, get reading and leave), 2 you go in during an off hour or non peak hour. This particular scale reads 24/7.
As for water in the foam? I’d give 99% odds on it. The foam used then (especially) by tracker, was substandard, compared to what most are using today. Even now, trackers foam isn’t good.

 

[thill]

Hey all,

I picked up a very used 2004 Tracker pro guide v16 WT with a merc 40hp 4 stroke 3 cylinder EFI.

Not that I was expecting to win any races, but this thing is a dog. Can barely hit 20mph in perfect conditions.

Anyone have a similar setup who can throw some knowledge my way? It gets to about 4800 of its 6000 max rpm. 10 3/8” x 11p 3-blade prop. Compression numbers looked great and doesn’t seem to misfire or anything. It just seems like a heavy boat for this motor.

The previous owner has the motor mounted on the highest hole, the anti-vent plate is about even with the lowest part of the hull.

Think it’s worth raising up 1-2 holes? Or do I have bigger power problems?

You probably need to drop to a 9P prop. You need to get the motor up into it's power band. I'd guess you might get another 5 MPH out of it if you get it just right.

Try raising it a hole or two to see if it helps first. That costs nothing, and you never know!

4-strokes make all their power up in higher RPM's. You need to get the RPM's up higher to see what it will really do on that hull, one way or another.