Sombody help me...

[17FishMan]

Just got back from first time out with my 2008 Lund 1750 Fisherman. Motor is a 115 Merc 4/stroke. Had four guys in the bost with limited gear and back live well 1/2 full. Boat would NOT plane with all four behind the windshield. Prop is a 17 pitch 13.25 aluminum. RPMs were around 5400-5600 at 40 MPH once we got her up. (WOT)

Wondering if a SS prop, and or smaller pitch can help with this, or am I going to have to upgrade the motor? I don't need to go faster, but the hole NO/shot is rediculos.

I need Help.....

[PerchJerker]

A different prop would help and is probably the best place to start, but that'a a big load in the boat. You should do your testing with a "normal" load in the boat, whatever that is for you.

Also, have you broke your motor in yet (you said it was your first time out)?? Running WOT is excessive if not broken in, and I'd hold off on prop testing until you have some hours on the motor.

You had the motor trimmed down (in) all the way when starting out of the hole, correct? Having the motor down will improve holeshot vs. having it trimmed out too far.

Good luck getting it figured out .....

[marine_man]

If this was your first time out you should have spent your time breaking the motor in (no long runs at WOT, vary your throttle speed for the first 6-10 gallons or so) instead of trying to get it on plane. I understand the desire to see what she'll do, but in the long run you're better off making sure the break in is done first.

It sounds like you had a full load in the boat, before I made any propping changes, and after I was done breaking the motor in, I would make another run with however many people you think you'll normally have in the boat, then post your RPM numbers.

I'm a bit surprised to hear that it wouldn't plane given your RPM numbers... it could use a slightly flatter prop, but I wonder if you were trimmed down all the way to start.

marine_man

[BobT]

Is a Fisherman 1750 a 17-1/2 foot aluminum, roughly?

I find it hard to believe a 115 couldn't plain that out. Brother-in-law owns a Mr. Pike 17-1/2 with a Yamaha 115 and it doesn't seem to know the difference between one rider or six.

I think a Fisherman has a walk-thru windwhield right? But does that add so much weight?

Bob

[17FishMan]

I guess I should have been more clear, I did get a chance to run the boat for the two hr. break in period last fall. What I had meant was it was the first time I got a chance to actually use it. What a great day on the water, Sunday.

And YES !!! the motor was trimmed all the way down.

[Hoffer]

How big were the guys in the boat?

Also, I noticed last Summer the difference in having my front livewell half full compared to fully drained made a huge difference in overall speed - maybe not hole shot but speed. Did you try putting one guy up front to see if it made a difference? if all 4 guys were in the back, and you had a half full livewell - that may be a lot of weight even for a 115 to plane right out.

My budy has a heavier boat - an 1850 Sporfish with a 115. His boat is a little underpowered - but we have 3 pretty big guys with lots of gear - and it powers up to plane right away. But he also runs a stainless steel prop - but even so your 115 on a much lighter boat should plane right out. I suspect prop issues or else way too much weight way in the back of the boat.

[hydro]

What is the load rating of the boat (passengers/motor/gear)? With 4 big guys, 100+ pounds of water in the live well and the weight of fuel you may have had quite a load. With all 4 guys in the back half of the boat that's a lot to push over onto plane.

[311Hemi]

My budy has a heavier boat - an 1850 Sporfish with a 115. His boat is a little underpowered - but we have 3 pretty big guys with lots of gear - and it powers up to plane right away. But he also runs a stainless steel prop - but even so your 115 on a much lighter boat should plane right out.

Hoffer, can you email me at zache****j1 (at) hotmail d0t com

I have a few questions on your buddies setup. Remove the **** from the email address.

[BoxMN]

See if you can find a dealer with the blue prop program (do they still have that?) that will let you check out two props at a time. Get a 3 blade 17 Stainless that is noted for "bow lift" (I don't think the Tempest goes small enough for a 115, but a similar prop type) and also I would recommend a Hi-5 to test, the lowest pitch they have. I think they make one for a 115, but not totally sure. I think they have ore models now in addition to Tempest and the 4 bladed Trophy. Stay away from a Laser for sure.

I drove a similar sized boat with a 4 stroke 90hp of a different brand, and I could not believe it - it could not get out of its own way. I would try to move some weight forward (anchor, tackle, etc.) until you find a better prop. The prop will most likely fix it for you, and if you want you can adjust height. We did all that testing on our motor and we found a sweetspot (150efi, though...) but we tested lots of props. Easier when you can hop in water and swap props in your swimsuit

Good luck, you will find right prop and motor height and all will be good.

[17FishMan]

What is the load rating of the boat (passengers/motor/gear)? With 4 big guys, 100+ pounds of water in the live well and the weight of fuel you may have had quite a load. With all 4 guys in the back half of the boat that's a lot to push over onto plane.

Boat is rated for 1045lbs, We had back live well half full, with minimal gear. Avg. body weight was probally 225, so I'm pretty we were with in boats weight capacity. Also, fuel tank was 2/3 full.

[boatfixer]

you are pretty darn close if not over. 225x4=900 lbs. that leaves 145 in gear and fuel, water, etc.

If you are going to regularly carry that size load, I'd consider a 4 blade or as box suggested, a High-5. Both should give you a better hole shot without sacrificing top end. The one thing you need to keep in mind is that if you drop way down in pitch to get a better hole shot with a large load, you need to be extremly carefull that you arnt going over max rpm with a lighter load.

I'd recomend going back to the dealer and have them work with you as well.

[BobT]

Doesn't that boat load capacity include the outboard? I know any boat I've owned did and does specify the load rating with the outboard.

Bob

[TMF89]

My only thing is that we run the same boat with a 19 pitch prop, which's been reccommended by a couple boat guys I know. If you find out the right deal, let me know though. Our's planes out fine, but it won't run top speed, and the RPMs won't get up to the right level.

[VMS]

Hiya,

Assuming your motor is a 2008, you should be upwards of 6400 RPM's at WOT under your normal load. With the load you had (close to max), a flatter pitched prop would be in order. With your RPM's down in the 5400 range, you are almost 1000 RPM's shy of your max...

If this is your normal load, it's lower pitch time...

Steve

[Down Deep]

I have a 17 Lund Explorer Sport with the same engine. I have a 15 pitch SS Solas that move this boat at 6400 40 -44 mph WOT loaded. The boat came with a 19 aluminum prop and I couldn't get it out of the water. Tried a 17 and although it was better it still wasn't at full capacity. I went to the 15 SS and it is performing at its peak with a load. When I'm by myself I have to watch the top end because it can over rev. As soon as the ice lets go I am going to try a 17 SS.

Call Soderblooms up in Cromwell and they can give you the advice you need. Their mail service is approx. 2 days.

[S.D. Ice Angular]

What is WOT??

[SimilarIsland]

Wide Open Throttle

[boatfixer]

Yes Bob it does. Motor and people puts him at about 1300#. Good call

[leech~~]

17fish, Where did you have your motor trimmed at, in or out? Make sure your motor is trimmed in as far as it can go with a big load to get the bow down faster. I seen a guy running around the lake all morning with a bunch of guys in a new boat not planing with the bow up. But he had his motor trimmed way out. After watching them go back and forth across the lake I buzzed over to them and suggested that he trim his motor in all the way to get the bow down, and he took right off. But never came back to say thanks! Try that or a faster pitch blade but that will take some off your top end speed. Good Luck

[BobT]

Will forcing the bow down help or hinder? My experience has been that trimming under too far prevents the boat from planing because your plowing with the front end. Trim under to get hole shot and then trim it up to plane out.

Bob

[leech~~]

BobT, I think you have to get the bow down as soon as you can when taking off or you will never get up to planing speed. You just keep plowing a long with the bow up. But you are right about trimming out once you get going up on plane. It's kind of like pulling a tuber, when their sitting the tube is at an angle. But once it starts to pick up speed it levels out flat and starts to plane.

[Down Deep]

You have to get the bow down and then trim it up once the speed picks up. This boat needs to have some push and a higher pitched prop is not going to get it moving.

[leech~~]

On some boats it's just the way it's trimmed out that will get it up, but on others a higher pitch prop will let the motor keep the RPM's higher which will move water faster, then a motor that is bogging down at lower RPM's. So both maybe the fix, it's just trying one and then the other. Trimming is cheaper then trying different prop's out because it costs nothing to push the buttom back and forth.

[boatfixer]

Higher pitch will decrease rpm. He's already stated he has had the motor trimmed in all the way. Sounds to me like the boat was overloaded.

[leech~~]

Darn 4 stroke! just get an E-Tect!!