Bass Tracker WOT at 7000 RPM ?

Hunterdan

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New guy here with a new boat. Well, new to me at least. It's a ;
2002 Bass Tracker 175 Pro
50HP mercury

I took it out today for the first test run and it did fine but I have a couple questions. The boat would max out at 31 MPH and 68-7000 RPM. I never run anything to it's max so I took it down to 58-6000 RPM and speed was at 24-25MPH. It has a vengeance stainless prop on it and I'm not sure if it's correct for the boat. It says on the back of the motor that max RPM is 5K. Should I get a prop that makes WOT 5K in RPM? I'd like to go as fast as possible but not running 7K in RPM. Any thoughts?

Thanks guys,
Dan
 

Bondo

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Re: Bass Tracker WOT at 7000 RPM ?

New guy here with a new boat. Well, new to me at least. It's a ;
2002 Bass Tracker 175 Pro
50HP mercury

I took it out today for the first test run and it did fine but I have a couple questions. The boat would max out at 31 MPH and 68-7000 RPM. I never run anything to it's max so I took it down to 58-6000 RPM and speed was at 24-25MPH. It has a vengeance stainless prop on it and I'm not sure if it's correct for the boat. It says on the back of the motor that max RPM is 5K. Should I get a prop that makes WOT 5K in RPM? I'd like to go as fast as possible but not running 7K in RPM. Any thoughts?

Thanks guys,
Dan

Ayuh,.... Welcome Aboard,.... What pitch prop is on it now,..??
 

Hunterdan

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Re: Bass Tracker WOT at 7000 RPM ?

Ayuh,.... Welcome Aboard,.... What pitch prop is on it now,..??

Numbers on the vengeance prop are;

48-855858 A 5 13P

Motor has a label that says 12x22

Again, it's running WOT 31 MPH at close to 7K RPM.

Thanks, Dan
 

jestor68

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Re: Bass Tracker WOT at 7000 RPM ?

With a 13 pitch Vengeance, you ought to be doing about 31 mph @ about 5300 rpm, which represents 11% slip.

Your tachometer is way wrong. Have it checked against a shop tach.

You might try removing the connector on the back of the tach and clean the pins. When they get gummed up, it usually makes the tach read high; sometimes way high.
 
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steelespike

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Re: Bass Tracker WOT at 7000 RPM ?

Seconded,Your numbers are right on but for your whacky tacky.
 

Hunterdan

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Re: Bass Tracker WOT at 7000 RPM ?

Seconded,Your numbers are right on but for your whacky tacky.

I was fixing to look at the connections and then noticed that the rpm gauge is resting at 1000 rpm while not running. Is there a way to re-calibrate it? There is a button on the backside that has a flat head slit in it with different numbers like 4C and such.

Thanks again, Dan
 

jestor68

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Re: Bass Tracker WOT at 7000 RPM ?

The tach can be reading something with the key off.

It should zero when you turn the key on.

The settings on the back can vary according to the brand.

If it reads like 1000 rpm when the motor is idling at like 750 rpm, the error usually gets greater as the rpm increases, so by the time the actual rpm gets up to 5000 rpm, the tach can be reading 1000+ rpm high.
 

H20Rat

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Re: Bass Tracker WOT at 7000 RPM ?

+1 tach is off... The engine has a rev limiter, most likely at 6000 rpm. But yes, you absolutely want a prop that puts you at the correct rated rpm at WOT. Doesn't matter if you never run that speed, the idea is to have the proper gearing on it. Otherwise its like driving a manual transmission car around in 5th gear all the time. You are lugging the engine at ALL rpm's.
 

Hunterdan

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Re: Bass Tracker WOT at 7000 RPM ?

The motor sounded and performed really well but the 7K rpm got me a bit concerned. Tomorrow when I take it out I'll check and see if the tac drops to 0 when I turn on the key.
Is there any way to make the needle point back to 0 when not running?

From what I've read the 2002 Mercury 50HP 2 stroke is supposed to be on either 4 or 6p setting. Does that sound familiar to anyone?

Thanks, Dan
 

Texasmark

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Re: Bass Tracker WOT at 7000 RPM ?

The motor sounded and performed really well but the 7K rpm got me a bit concerned. Tomorrow when I take it out I'll check and see if the tac drops to 0 when I turn on the key.
Is there any way to make the needle point back to 0 when not running?

From what I've read the 2002 Mercury 50HP 2 stroke is supposed to be on either 4 or 6p setting. Does that sound familiar to anyone?

Thanks, Dan

Depends on the alternator. Mine and a lot are 12 pole and that requires the 6p setting on the Quicksilver Tach. Just a quick arithmetic and if you were in the 4 vs the 6 or vise versa not important for this answer, the ratio is .66666666. Multiply that by your whacky-tacky number and you get 4999 for your real rpm which is where you want it pretty much. So, how about changing from whereever your tach is set to the other number.

Mark
 

Hunterdan

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Re: Bass Tracker WOT at 7000 RPM ?

I put the tach setting at 6P and took it out yesterday. I noticed when I turned on the key it dropped from 1K to zero. From then on it stayed at zero when the key was off. When cranked it was at 11-2000rpm in neutral. If I put it in gear it dropped to 900-1000RPM. At WOT throttle it went to 57-5800RPM. It sounded good and felt right at 53-5500RPM with my wife and two kids and maybe 50 lbs of gear including the 15lb anchor. It was running at about 22-23MPH at those numbers.

I did notice after a few stop and go's that the rpm, battery and fuel gauge quit working. After turning it off and re starting the motor they would all start working again. I also noticed that sometimes the starter wants to keep spinning after it's cranked but I just made the key go back to run position...manually.
One other thing....I noticed that the motor gets a bit of a rattle sound when in between mid and 3/4 throttle then it goes away until at WOT. If I back it off WOT a bit then it smooths out and sounds good. Any ideas what that could be? I used 87 octane and added some ethanol treatment.

Thanks all for the help,
Dan
 
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Texasmark

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Re: Bass Tracker WOT at 7000 RPM ?

I put the tach setting at 6P and took it out yesterday. I noticed when I turned on the key it dropped from 1K to zero. From then on it stayed at zero when the key was off. When cranked it was at 11-2000rpm in neutral. If I put it in gear it dropped to 900-1000RPM. At WOT throttle it went to 57-5800RPM. It sounded good and felt right at 53-5500RPM with my wife and two kids and maybe 50 lbs of gear including the 15lb anchor. It was running at about 22-23MPH at those numbers.

I did notice after a few stop and go's that the rpm, battery and fuel gauge quit working. After turning it off and re starting the motor they would all start working again. I also noticed that sometimes the starter wants to keep spinning after it's cranked but I just made the key go back to run position...manually.
One other thing....I noticed that the motor gets a bit of a rattle sound when in between mid and 3/4 throttle then it goes away until at WOT. If I back it off WOT a bit then it smooths out and sounds good. Any ideas what that could be? I used 87 octane and added some ethanol treatment.

Thanks all for the help,
Dan

Well it looks like you got your Wacky-tacky fixed.

The service manual for my engine states that the rpm should be 675 +/- 50 idling in the water in F gear (engine loaded). Your idle numbers aren't that bad.

Moving on, it sounds to me like a bad ignition switch in the remote control. The dragging starter part of the problem could very well be dirty contacts in the switch bleeding over too. What happens on the starter is that the solenoid is still getting enough power to remain engaged (takes a lot less current to "hold" a relay as compared to energizing it) and keeping your starter engaged. Your comment about "after a few on-offs, my............" is indicative of bad switch contacts.

On the rattle and your 25mph and 5500 rpm: With your 1.64 gear box, 5500 rpm, and a 13P prop, the BAM prop slip calculator says that your non slip speed would be 41 mph. Plugging in your 25 mph says that you have a 39% slip. WAY too high indicating that either you have an instrument error (speedometer) or the prop could be slipping which could account for some of the squealing. For a reasonable (high end number for that boat) 15% slip you would be running about 35 at your 5500.

Pull your prop nut off and mark a line from the shaft (brass spline part) out to the SS prop material. Put it back together and run it hard. Pull the nut back off and check the line. If not as you marked it your hub is slipping.

Mark
 
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Hunterdan

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Re: Bass Tracker WOT at 7000 RPM ?

Well it looks like you got your Wacky-tacky fixed.

The service manual for my engine states that the rpm should be 675 +/- 50 idling in the water in F gear (engine loaded). Your idle numbers aren't that bad.

Moving on, it sounds to me like a bad ignition switch in the remote control. The dragging starter part of the problem could very well be dirty contacts in the switch bleeding over too. What happens on the starter is that the solenoid is still getting enough power to remain engaged (takes a lot less current to "hold" a relay as compared to energizing it) and keeping your starter engaged. Your comment about "after a few on-offs, my............" is indicative of bad switch contacts.

On the rattle and your 25mph and 5500 rpm: With your 1.64 gear box, 5500 rpm, and a 13P prop, the BAM prop slip calculator says that your non slip speed would be 41 mph. Plugging in your 25 mph says that you have a 39% slip. WAY too high indicating that either you have an instrument error (speedometer) or the prop could be slipping which could account for some of the squealing. For a reasonable (high end number for that boat) 15% slip you would be running about 35 at your 5500.

Pull your prop nut off and mark a line from the shaft (brass spline part) out to the SS prop material. Put it back together and run it hard. Pull the nut back off and check the line. If not as you marked it your hub is slipping.

Mark
It says 1:83 on the motor for gearing. Does that make any difference in your calculation?

Also I believe the rpm was closer to 5K instead of 5500 and moving 25MPH. Weight of my wife kids and I was was 550 + the motor weight. I believe the tag says combined weight including motor not to be over 580+/-.

I also had a full tank of fuel.


Thanks, Dan

Thanks, Dan
 
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Texasmark

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Re: Bass Tracker WOT at 7000 RPM ?

You can figure it out. Go to Prop Slip Calculator. Plug in 1.83 for gear ratio. Fill in the remaining known info and solve (calculate button) for Max (no slip) speed........speed as if the prop were a screw thread turning through a solid medium. Then "guestimate" your slip which will be in %, like put in 15 for 15% slip and punch the final box where it says calculate. The slip depends on lots of things but gives you an idea as to an area where you may be operating. Prop type, hull shape, and weight are the big variables. 15 is a good average number I'd say. Light, fast boats would be more up in the 10 area and tubs down in the 35 or so area.

HTH,
Mark
 
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