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Posts: 349
| 06 E-Mag tiller with a 60 Suzuki, 13.5 x 15 aluminum prop. The boat runs great, good hole shot and around 31 mph @ 5200 rpm top speed.
My only issue is that if I trim up at all while on plane the boat starts to porpoise almost immediately. I was told this is normal for that hull, but can't find any information to confirm that's the case. I'm looking for others with e-mag experience to figure out if that is normal or if I need to make some changes. |
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Posts: 32786
Location: Rhinelander, Wisconsin | Not normal, your prop is a suspect first, don't know enough about Suzi props or mating Merc wheels with that motor, but stainless is a good idea. What is your engine height? How many batteries in the front?
If you wish, you can wedge the motor with a 5 degree motor wedge set really inexpensively and do nothing else at all. Not a bad idea to re-seal the motor bolts on that bad boy anyhow.
https://www.carid.com/t-h-marine/pair-reverse-transom-wedge-mpn-tw-3... |
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Location: Northern Wisconsin | Try moving weight forward, if possible. |
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Posts: 859
Location: MN | Can you fill a front livewell? |
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Posts: 443
Location: Duluth, MN | A hydrofoil will probably get rid of it and improve your holeshot a bunch. |
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Posts: 3469
Location: Elk River, Minnesota | Hiya!!
Before going too far, my suspicion is that we have an over-pitched prop on the boat. If this is a 4 stroke 60hp motor, it has a low gear ratio (current is 2.29:1) which is a great thing for low end torque. RPM specifications list 5300 to 6300 at wide open throttle, so with running 5200 on your rig as it stands, I am thinking you are over-pitched by about 4 inches.
The boat itself is close to 1000 pounds, so getting 31 mph is honestly quite good...but...if the specs have not changed from when you purchased to todays model, the over-pitch of the prop is what is definitely causing your issues.
When a motor is over-pitched, it has a tendency to porpoise badly when trying to trim up because there is so much downward force at the rear, but not enough RPM's to keep the bow up...thus, the bow rises and falls because of the lack of rpms. So...going down in pitch will allow the motor to reach higher rpms, and allow the motor to turn enough to keep the bow up while trimming.
At 60hp, a steel prop will not give much of a performance gain, but it will give you some durability and less flex. I'd stay stay with aluminum, but go to a good aftermarket like a solas propeller. They used to carry what they called the allcup series, but I think that has been updated to the Amita Series. These are a good style of prop as their casting is a bit different than a normal aluminum...they are squeeze cast, which means they are under more pressure in the casting process, thus allowing them to make a thinner blade. You get the best of both steel and aluminum...less flex in the blade like steel, but yet the price and softness of aluminum if you hit something. Granted, at full throttle, the prop metal will not make a difference...damage will happen...but for both durability and performance, it is tough to go wrong with solas.
I'd highly consider going to an 11 pitch propeller, which would gain you about 800 RPM if memory serves me correctly. going up 800 rpm would give you the rpms you need at full throttle to maximize the efficiency of the engine. Being the boat is heavy, I'd even consider going 4 blade, which would allow you to move the motor up a hole or two to maintain your rpms.
I'm one to feel that the only boats requiring a fin are those that are underpowered...in your case for a tiller model, the 60 is max hp, so adding a fin to that is only disguising the issue, and you would still be lugging the motor. When rigged correctly, the fin would not even be in the water at wide open throttle.
My gut says...go to an 11 pitch prop 3 blade, then move the motor up one hole. If you go 4 blade, go up 2 holes. In the end, I think you will feel like your boat will wake up and really be a nice rig to run...
Steve |
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Posts: 32786
Location: Rhinelander, Wisconsin | Buy a stainless in the correct pitch; I've owned several Magnums nad sell a number of them each year, and they love a matched stainless prop. As I said, I'm not familiar with the Suzi props to make a recommendation, but the prop is definitely part of the problem. Don't go up two holes, you may cavitate. |
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Posts: 3469
Location: Elk River, Minnesota | Hiya again!!
If the prop is a good stainless....most likely aftermarket, going up 2 holes off the transom will likely ventilate at the maximum trim angle the rig can get to and trying to make a moderate turn at the same time. In most cases such as this, a quick bump down in trim to make the turn is used, then trim back up while running straight. Trimming down allows the bow to help carve the turn.. Having to make small adjustments like that mean your rig is running quite efficiently... in most cases, the higher the motor is mounted and propped correctly, the boat will ride higher as well..
I don't believe Suzuki will makes a steel prop in the size you would need according to the website... they have aluminum down to 14 x 11 pitch. Steel options will be limited for selection but they are out there....michigan, solas, power tech... I'm not sure you will be successful in finding an 11 pitch steel... I have not researched that size and pitch, but will do so..
Trim is something that always is in constant adjustment depending on conditions..
I believe Mr Worrall and I are on the same page...he has much more experience with tuffy rigs, so going up higher could very well be correct if the Esox transom by design is higher than others...
Steve
Edited by VMS 5/18/2017 10:12 AM
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Location: Eastern Ontario | Alumacraft told me that typically Suzuki's need to be mounted higher it could be this may also apply to Tuffy the ultimate set up sometimes requires a bit of trial and error. Steve VMS seems to know his prop setups he was able to help me a couple of years ago. |
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Posts: 349
| I have 2 agm batteries and a 3 bank charger in the front battery compartment. Anchor and other gear fill the front storage, so I can't really move weight forward. I don't know where the motor is mounted off hand, so I'll check that tonight and report back.
VMS, as to the prop selection and rpm's... My research showed rpm range of 4300-5300 - https://www.rubexprops.com/boat-propellers/rpm-range/?make=Suzuki - I have the solas amita prop you mentioned and from what I know, the rpms are right in the money. Motor is a 2006.... Maybe that website is wrong?
Thank you Steve and Steve for the quick responses, greatly appreciated. |
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Posts: 349
| ^^rpm range 4700-5300, not 4300 |
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Posts: 349
| The motor is mounted on the second from the bottom hole; it could be moved up 3 holes. |
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Posts: 47
| There's some pretty good advice here but confirming some details can help with a solution. If your WOT (Wide Open Throttle) RPM range is really 4700 - 5300 it sounds like your motor is a DF60 made between 1998 and 2009. If that is the case your lower unit has an even slower gear ratio - 2.42:1. Based on my boat speed calculator @ 5200 RPM you should not even be able to get to 31 mph. 30.5 mph would be it in a perfect world with zero prop slip. Most rigs will show about 10% slip give/take a little. If you are using your dash speed indicator instead of a GPS your top speed figure is most likely in error.
The fact you are able to get to 5200 RPM suggests that your are not significantly overpropped. If you dropped an inch of pitch to pick up your absolute WOT RPMs your top end would be around 26 mph factoring in 10% prop slip. On a motor that age, unless you've run Seafoam every tank and/or de-carbonized it, you may not even realize 5300 regardless.
Weight distribution (as noted) can be critical in boat performance and becomes more and more important the faster your wish to go. If you have power tilt/trim you can try trimming down a little lower than you have been running. I tend to ignore the "trim gauge" as a benchmark for adjustment rather use my boat performance and observe the relative indications it provides. I then duplicate that going forward. Mine does best when the gauge indicates just a little under dead even. It provides the best balance of top speed, handling and the ability to reach max RPMs. If your trim setting is manual (pin in the hole) maybe try dropping down one hole. This would keep more bow in the water and help your control.
I've only had enough experience with this stuff to be "half dangerous". I learn something new every day. Maybe this will be one of those times... Keep at it, you'll get it figured out. There's some pretty savvy folks chipping in.
Edited by otto 5/18/2017 6:48 PM
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Posts: 8
| I have owned multiple Esox magnum 4 tillers tillers and 1 console. They like to porpoise. Especially when restricted to lower hp with tillers. I have had best performance drop motor as low as you can go. Use a prop with extra cup.
My past 2 (and current) were equipped with Mercury big foot 50 hp 4 strokes( which require installing tiller conversion kit) The large cavitation plate works great but it will still porpoise if given 2 much trim.
I run with 2 batteries up front and usually a partner seated in center.
Full load and 2 in boat speed 26 mph. Just me planes better at 29.
Go low and order prop with extra-cup that is about as good as it will get. |
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Posts: 3469
Location: Elk River, Minnesota | Hiya,
I was going off of current motors, as I was unsure of what model you had, so I do stand corrected...
With that being the case, you are not too far off then, which is a good thing...so...Steve Worrall's suggestion of adding the wedges might help with the solution.
I'm thinking for trim purposes also that maybe too much weight up front could be part of the issue as when you trim up, the motor cannot keep it there due to the weight.
I do think finding a prop that has some good tip-cupping would be very beneficial as well, but plan to go down in pitch about 2 inches. The tip cupping will reduce rpms but help lift the bow and keep it there so long as you keep your rpms up. This will most likely allow your rpms to be right around 5400 or so (given you go steel), but hopefully give the bow some more lift.
Steve
Edited by VMS 5/19/2017 9:06 AM
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