Lund Impact 1775 cavitation and other issues

[T Mac]

Originally Posted by Anders31

Hello,

So I have a 2016 Lund Impact 1775 with a Mercury 115 on it. I'd like to first say I will likely never purchase or recommend a Lund product after the problems I've dealt with on this new boat with maybe 10 hours on it. I've also received virtually no help from Lund or my dealer. Basically stating it's normal. Our last boat was a 1990 Sylvan with a 110 Evinrude that ran without issues whereas this new boat has been a PITA.

Onto the problems....

It cavitates REALLY bad, unless you have the trim perfect which seems to be all the way to the left (not in the middle which is where I'm use to) it won't get up to speed easily and feels as though the motor is causing a lot of drag if that makes sense.

If and when you turn you have to keep adjusting the trim otherwise it sounds like the motor is over revving and the boat slows down very quickly.

It also seems to go through gas quickly and I'm guessing that's because of the issues I'm describing. It just seems like the motor is having to work very hard.

Hard steering to the left is also another thing.

So anyone else have these problems? We've thought about trying a trade in for an AlumaCraft or something. This boat has just been an annoyance because of these issues I pointed out. Could a new stainless prop help and maybe moving the motor? Just sucks you can't get a new boat without having to mess with things. It currently has a 4 blade Mercury prop that the dealer gave to me to try.

Very simple issues to fix,and here's why.

... This is happening because Mercury shortened the engine about an inch when they came out with the Pro XS version of 115.
Also... I don't care what it says on paper... the aluminum spitfire does not work well on these new 115's and 90's....unless they are mounted all the way down on the transom. (The aluminum Spifires do work well on 30-60hp engines).

The result is:
1) The engine needs to be mounted in the lowest position on the transom for using an aluminum prop. Looks like that has been done.
2) The Mercury aluminum Spitfire does not work well on the 90 and 115. from any testing I was involved with .
-----A Black max 3 blade prop works better.
-----A four blade Stainless X-7 works great....and it will work excellent where your engine mounted up one hole,as well.


Once you get the right prop on an outboard engine it is like a whole different rig.
It is amazing the difference.
I have always said ... putting an aluminum prop on anything 115 and up is a sin. . It wastes the benefits of a great hull.

One tip: It is normal to trim down when turning to avoid the blow out associated with high trim.
Naturally it will happen a lot less with a prop stays hooked up better.

[shell_guy]

Originally Posted by T Mac

Very simple issues to fix,and here's why.



... This his happening because Mercury shortened the engine about an inch and a half when they came out with the Pro XS version of 115.

Also... I don't care what it says on paper... the aluminum spitfire does not work well on these new 115's and 90's....unless they are mounted all the way down on the transom. (The aluminum Spifires do work well on 30-60hp engines).



The result is:

1) The engine needs to be mounted in the lowest position on the transom for using an aluminum prop.

2) The Mercury aluminum Spitfire does not work well on the 90 and 115. from any testing I was involved with .

-----A Black max 3 blade prop works better.

-----A four blade Stainless X-7 works great....and it will work excellent where your engine mounted now.





Once you get the right prop on a boat and the engine it is like a whole different rig.

It is amazing the difference.

I have always said ... putting an aluminum prop on anything 115 and up is a sin. . It wastes the benefits of a great hull.



One tip: It is normal to trim down when turning to avoid the blow out associated with high trim.

He is having a hard time turning left and can trim all the way out on the gauge without blow out. These are signs the motor is too low already, I would bet my pay cheque that the motor needs to go higher.


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[T Mac]

Originally Posted by shell_guy

He is having a hard time turning left and can trim all the way out on the gauge without blow out. These are signs the motor is too low already, I would bet my pay cheque that the motor needs to go higher.


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I need to type faster... LOL. And need a provider who loads stuff more quickly.
When I started typing,... only his 1st question was there...I never saw the second.

.
.

[shell_guy]

Originally Posted by T Mac

I need to type faster... LOL.

When I started typing,... only his 1st question was there... nothing else.

.

Haha all good, I didn't even notice he edited it. The newer ips and ips2 hulls come out of the water a lot and usually benefit from the av plate being 1-2" above the hull.

I am actually considering a jack plate for my 1775 ProV.


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[T Mac]

Originally Posted by shell_guy

Haha all good, I didn't even notice he edited it. The newer ips and ips2 hulls come out of the water a lot and usually benefit from the av plate being 1-2" above the hull.

I am actually considering a jack plate for my 1775 ProV.


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Yah ,... I know..
I did a lot of the prop testing for Lund in 2015 and 2016.

[John69]

TMAC

Interesting comments on the Pro XS being mounted all the way down (mounted top hole). My 2017 1775 SS , 115 Pro XS came factory mounted in top hole and I was concerned after reading quite a bit about performance. I'm still in early break in ~3 hours but here's some results from over weekend:

- 3/4 full fuel
- 1 person in boat with fishing load
- 4 batteries (2 bow / 2 rear)
- 9.9 kicker
- 19P aluminum Spitfire

Straight away trimmed between 1/4 and 1/2 hitting 5800 rpm about 43-44 mph. Yes, if I turn at any sort of steep turn blowout exists. I told myself I'm going to run it this year to get some hours on it and maybe play with props next year. Performance is perfectly fine for the way I fish though.

[martinbns]

Originally Posted by Waterboy12

I had a 2012 1775 Impact with a Merc 115 four stroke. I was shown on the water how to use the trim by the dealer, before taking possession of the boat. It was different from my previous boat, which did not even have a trim button. I was told to start out completely trimmed in, to get on plane. Once on plane, adjust the trim out, until at optimal performance. It did not take long to figure out where that spot was, and it eventually became second nature.

The 2012 Impact came with the aluminum Black Max, 13 X 19. It planed very easily, and quickly got to speed. If memory serves, top speed was just around 40 mph, at around 6000 rpm. On sharper turns, I had to trim in a bit to avoid cavitation. Again, it eventually became second nature. I had been told on this site, and elsewhere, that a stainless prop would help to avoid blowing out on turns. Before I managed to try different props, I traded in the boat -- for another Impact. I just went a little bit bigger, with a layout a bit more to my liking the Impact 1850 XS, with Merc 150 four stroke. This one came with a a stainless prop, the Tempest Plus, 13 X 19, and trimming down on turns has not been necessary in most cases. It rides beautifully.

As to your issues, here's my non-professional advice. As far as trimming, take the time to learn your boat before getting upset and looking for something else. All Makes and models are different, and will take a bit of time to find best performance. Ten hours is barely engine break-in time. Your motor should not struggle to get up to speed. I think I would get a Merc mechanic to go out on the lake with you to see if he can figurte that out. I believe my motor on the 1775 Impact was mounted second hole from the top. Wherever it was, it was where Lund recommended it be. Maybe there is something that needs to be fixed, or adjusted, because that 115 four stroke should be a sipper, not a guzzler.

I hope you find your answer, and begin to enjoy the boat.

I have a Rebel 1750 XS with the 115 4Str, I was shown the same way of getting the right trim, get on plane with it all the way down, they trim up until the bow stops bouncing in the waves. I find I need to trim down slightly when turning hard. When I was first getting used to driving the boat in chop, I found I was over trimming. I have a 19p Spitfire prop and am very pleased.

[Northwoodswalleye]

I've had many boats and until I put a 4-blade stainless prop on my 1875 impact I had similar issues as you. Last boat was an Alumacraft voyager 175 and it was nowhere near as touchy with trim. I could leave the trim where it ran fastest and the boat would take off and get right on plane and go without trimming down. This boat would never do that without cavitation. I used a 19p SS tempest which was better than the stock aluminum prop but not anywhere near as good as this 4-blade. I went with a bravo 1 FS 20p that I found used on eBay. The ips hull is different than the Alumacraft hull and when you trim it to the sweet spot you can feel the boat lift up on the pad and get a bit squirrelly for a second. Way different than driving a "normal" tin boat. With a 4-blade on my boat I'm in the 4th hole from the top and I can turn without touching the trim and it feels like it has power steering now.

[Capt Morgan]

Even though I have a different aluminum hull (crestliner) going to a stainless steel prop made my boat come alive. From an aluminum prop to ss, made a world of difference. My performance jumped up about 17%… With a lot better hole shot.

[RoughWaters]

My current boat is a 2016 1775 Impact with 115 mercury 4S. The prop I chose is the spitfire x7, in 17 pitch. This combination is awesome and I highly recommend it for this setup- it will run 43-44 all day long, holeshot is great, and RPMs are right at 5950 at WOT. When trimming the motor, I don't even look at the gauge. It only took me a few times on the water to play around with the trim and "feel and hear" the sweet spot.