Minn Kota 40 Lbs. vs 55 Lbs. Performance the same !!??

[Rey3475]

I've used a Minn Kota Endura 40Lbs. for over three years, and have had good luck with it. Last winter, the wind blew me off my favorite lake, and I decided to go for more power! I just purchased a new Minn Kota Endura C2 55 lbs. & went out on the lake today to try it out. I also left the older 40 Lbs. on the transom, so I could compare the performance of both motors. This is what I found.......same boat, same battery condition, same water conditions, etc.etc......The new C2 55 Lbs performed exactly as the 3 yr. old 40 Lbs. motor.....what gives ?? Both motors produced the same speed at each forward setting (1-5), within 0.1 knts. The 55 also has a small vibration at all speeds (worse at #5), where the 40 has none. Is there a "break-in period" ?? Are there any replacement props. for more power/speed ?? I may either have a defective new 55, or I have had the best running 40 ever produced. Any ideas as to what may be going on ???

 

[Silvertip]

Re: Minn Kota 40 Lbs. vs 55 Lbs. Performance the same !!??

Load up the boat and try the test again. You will find the 55 will outperform the 40. Both motors spin the same approximate speed. Props are selected for 2-5 mph at those rpm so speed will be the same. It is only when you apply more load that the 55 shows its stuff.

To illustrate this more clearly, consider a 15P prop on a 50 HP outboard and a 15P prop on a 200 HP outboard. Both engines run about the the same RPM wide open and if both had the same gear ratio in the lower unit, both would move the boat the same speed. However, load up the boat and the 200 will run away from the smaller engine.

 

[Rey3475]

Re: Minn Kota 40 Lbs. vs 55 Lbs. Performance the same !!??

Thanks for the info. The boat is a 14' Hi Laker, and it had 190 lbs of batteries, and 220lbs of old retired guy, plus fishing gear. That's a pretty good load. The 40 ran at 2.5 knts in position #5, and the 55 ran at 2.6 knts. Does this sound about right ?? Are there any other props available for a bit more speed from the 55 ?? Thanks again !

 

[fishrdan]

Re: Minn Kota 40 Lbs. vs 55 Lbs. Performance the same !!??

Nope, no break in period. The vibration is either a tweaked prop or shaft. Try pulling the prop and spinning it 180*, see if that gets rid of the vibration. I've had bent shafts before that caused vibrtion. I took a dial indicator and found the low side, then tapped it with a small hammer, kept at until the shaft ran perfect, no run-out. Though, you shouldn't have to do this with a new motor.

For the 55 pushing the boat the same speed as the 40, I'm not sure on that one. Maybe the motors turn the same RPM (at the different speed 1-5) and the 40 is turning the prop at full speed all ready. IE: the 55 can't spin the prop any faster than it's spinning all ready, motor RPM is maxed out. Just a guess though as I'd think the 55 would perform better than a 40. Get in some wind and waves and I bet the 55 does better than the 40. I know my 40 performs better than my old Endura 30 (higher speed and more thrust in each speed setting),,, and my 70# Vector will smoke the 40# Endura.

Is your TM wired direct to the battery(s) or going through extension cables? If using extension cables, how long is the wire run and what is the size of wire is being used? Too thin of wire could limit the power going to the new 55# motor and making it seem weak. Poor battery or wire connections could cause power loss too.

What does the prop on the 55 look like, same as the 40's prop, as far as design goes? I read somewhere that the newer "Weedless Wedge II" props don't perform as well as the older props. I can't verify that though as I don't have anything with a WW2 prop. My Vector is supposed to have a WW2 prop, but I swapped it out for a 3 blade MotorGuide prop (it fit with a bit of tweaking).

 

[Rey3475]

Re: Minn Kota 40 Lbs. vs 55 Lbs. Performance the same !!??

The cables are 2-0 battery cables that run about 12', so the voltage drop is minimal. I'm an old retired electrical engineer & delivery skipper, so I'm pretty careful about my connections and contacts....good question though. It was about 36 degrees today on the lake, with 38 degree water temp. The temp. may have affected the performance of the motors....I know it affected mine. I'll check the run-out on the shaft, & put a few more hours on the 55. I may also look into a prop with a bit more pitch, & take a look at that motorGuide 3 blade. Thanks for all the help !

Almost forgot....the prop. on the 55 looks just the same as my 40, just very slightly larger. It's not turned up at the ends like the Vector.

 

[fishrdan]

Re: Minn Kota 40 Lbs. vs 55 Lbs. Performance the same !!??

Check the motor housing diameter on your 55, if it's 3 5/8" a Motor Guide 3 blade, 3 1/2" prop might fit with a couple modifications, at least it worked on my 70# Vector. The outside edge of the prop (where it meets the motor) will need to be trimmed a bit, I chucked it up in my drill press and hit it with sand paper, took off about 1/32" and round of the edge. The prop body is shallower (than my 70# Vector WW2 prop) and I needed a 1/4" washer/spacer. I took a hole saw and cut 2 - 1/8 aluminum discs and epoxied them together. It's possible you might not need to do all of this, or it might not work at all, but it's worth a try.

I have a MotorGuide 70# bowmount TM that I took the 3 blade prop off for experimentation with the Vector 70#. (FWIW, I think 50-70# are the only MinnKota's ones that will match up with MotorGuise 3 1/2" props, as the motor housing is 3 5/8". I'm not 100% sure on that though.)

I checked my 40# Endura prop against the MotorGuide 3 1/2" plastic prop. The blades on the MG plastic prop were larger (1/4" wider and 1/2" longer) and there's that extra blade. MG also has 3 different 3 blade props; plastic, glass filled and aluminum. I have a plastic and an aluminum,,, and the blades are a bit different size, aluminum blades are wider and slightly shorter. I don't know how the 2 MG props I have compare as I haven't run the aluminum prop yet. I got it as the plastic prop seemed to flex too much and flatten out on high speed, probably work fine on a 55# motor though...

 

[fishrdan]

Re: Minn Kota 40 Lbs. vs 55 Lbs. Performance the same !!??

Something else I just found with the MG 3 blade props (plastic, glass filled, aluminum), they have a different pitch, at least the plastic and aluminum. From the leading edge to the back edge of the blade, the aluminum prop is about 1/4" more, measured at the prop body. This isn't 100% accurate as I was just eye-ballin' it, but there is a difference.

I'm going out tomorrow and if I get a chance I'll swap the props and see what the difference is. I'll be in my 14' jon boat with a speed wheel speed'o so I should be able to figure out what the difference is.

 

[keninaz]

Re: Minn Kota 40 Lbs. vs 55 Lbs. Performance the same !!??

I have found in my research that trolling motors are propped to do 3-5 MPH, period
Additional thrust is only for fighting the wind and water you may be slapping.
Minn Kota recommends 2# of trust for every lb. of loaded boat minimum
Anything more than that just just additional thrust for conditions.

 

[BoatNoobie]

Re: Minn Kota 40 Lbs. vs 55 Lbs. Performance the same !!??

I have found in my research that trolling motors are propped to do 3-5 MPH, period
Additional thrust is only for fighting the wind and water you may be slapping.
Minn Kota recommends 2# of trust for every lb. of loaded boat minimum
Anything more than that just just additional thrust for conditions.

I have to assume you meant to put in 2# of thrust, for every 100# of boat? Otherwise, that's a lot of thrust needed, lol.

 

[keninaz]

Re: Minn Kota 40 Lbs. vs 55 Lbs. Performance the same !!??

Yes I did, just got going too fast.