# Prop blow out??



## teleman37 (Apr 12, 2013)

Hi all,

I just bought a new Lund 1875 Impact with a 150 four stroke. Took the boat out for it's maiden voyage today. I was breaking in the motor, varying speeds constantly with some short wide open bursts. I have the motor trimmed all the way down for the holeshot and try to trim up as the boat planes out but I can't trim hardly at all without the motor rapping up.

My trim gauge is hardly showing any up trim at all, but it seems like it wants to blow out. I'm running a 19 pitch factory aluminum prop and my motor is mounted in the second hole from the top.

Anyone have any suggestions on what could be the problem here?


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## Shortdrift (Apr 5, 2004)

but I can't trim hardly at all without the motor rapping up.?????

What is "rapping up"? Over reving? Caviting? Bogging down?


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## teleman37 (Apr 12, 2013)

Over revving....cavitating. It does not bog down.


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## 2120Tom (Jul 2, 2008)

With the boat on the trailer and motor down in run position, where's the lower unit cavitation plate in relation to the bottom VEE of your hull ? they should line up REAL close. 
Boat/motor combo seems more than compatible, wouldn't think a 19p prop (of proper diameter) is too high to be blowin' out....if the motor height is right.
Talk with your dealer, he should know best what props work or allow you to try props until it's right.....maybe a four-blade. Good luck, you'll get it right at some point.


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## Legend killer (Apr 20, 2011)

Did you buy it from buckeye?


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## teleman37 (Apr 12, 2013)

No, I bought it from Victory Marine in Fremont, Nebraska.


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## cjbrown (May 22, 2007)

My money is on the motor being mounted way to high.....Or one other thing, shaft length. What make and model of motor are you running?


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## teleman37 (Apr 12, 2013)

cjbrown.... I only have one hole left at the top to lower it. The motor is a Mercury 150 four stroke.

The cavitation plate is right at the bottom of the boat when the motor is in the full down trim position.


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## cjbrown (May 22, 2007)

Do you have the model number on the motor or know for sure you have long shaft motor?


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## cjbrown (May 22, 2007)

What lake do you frequent?


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## teleman37 (Apr 12, 2013)

I live in Wyoming and have only had the boat for a day. I was doing motor break in on a small lake outside of town. Holeshot is great, planes quickly, but if I trim up just a little it blows out.

The motor is a 150XL four stroke. The boat is brand new, set up by the dealer. I can't imagine he would install a 20" shaft motor on a boat designed for a 25" motor??


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## cjbrown (May 22, 2007)

teleman37 said:


> I live in Wyoming and have only had the boat for a day. I was doing motor break in on a small lake outside of town. Holeshot is great, planes quickly, but if I trim up just a little it blows out.
> 
> The motor is a 150XL four stroke. The boat is brand new, set up by the dealer. I can't imagine he would install a 20" shaft motor on a boat designed for a 25" motor??


 I just ask that so all bases are covered, you just never know. I did a lil google, several instances of that same setup was found. Just might take a lil tweaking with diff props. Don't be discouraged, you have a damn nice setup. Even if 1000 boats have the same setup, you'll find some just have a personality of thier own. I'd call the dealer and see if he'll send you a couple props to experiment with. If he's a good dealer, he should. Good luck. It'll work out, just tweak and get to know her.


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## teleman37 (Apr 12, 2013)

Thanks cj! The dealer is on my call list for Monday morning. I will tinker with it and see if it's something that I am doing wrong, but I don't think I am.


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## GPtimes2 (May 14, 2006)

Might look into (google search) 4 blade stainless props and what they can do for you. Hope you enjoy the boat!


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## Legend killer (Apr 20, 2011)

A prop is not a miracle part. It sounds like your motor is to high. Take the boat to a local shop or post some pics on here?


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## sherman51 (Apr 12, 2011)

if the cavatation plate lines up with the bottom of the boat like you said it is then that is not your problem. maby you are just trimming it more than you think you are. but going to a 4 blade prop could make a big difference. if your getting a good hole shot how does it perform at mid range and wot??

when you trim your motor dont go by the trim guage, they can be off by quite a bit. just trim it up a bump at a time untill the bow of the boat starts to bounce. then trim it back down just alittle.

keep us posted on what you try and what works for you.
sherman


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## teleman37 (Apr 12, 2013)

Thanks for all the replies guys! I called the dealer and talked to him. He told me they no longer setup the engines on the boats, they come directly from Lund pre-mounted.

I would think that the factory has done extensive testing on where to mount the engine, and it should be right where it is. 

To clarify; I'm not a novice boater. I have owned numerous boats over the past thirty years. This is my first four stoke that I have owned though, but an outboard is an outboard. 

I am not trimming the motor hardly at all. I don't go by the trim gauge as I have never had much faith in their accuracy. The boat doesn't come close to porpoising before it starts to blow out????


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## I Fish (Sep 24, 2008)

It sounds to me like you're mounted too high. Before I started switching props, I'd lower it to the top hole and try it, it won't cost you anything but about 30 minutes. It'll only be about 3/4" difference, but might be all you'll need. It's amazing how much difference just a 1/4" can make. 

Also, check out the iboats forums. It's probably already been covered. 
http://forums.iboats.com/forum.php


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## Legend killer (Apr 20, 2011)

I would contact lund directly. Its ridiculous that you buy a expensive new boat and it has issues. They can have another dealer fix it under warranty.


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## Bad Bub (Jan 17, 2006)

It's very common for aluminum boats to have the issues your having. Usually you'll need to wait until your break in is done before you start moving things around or changing props. You'll need to make extensive runs with each change to see what is truly helping/hampering performance. Like was said previously, no 2 boats are the same, especially aluminum boats. Also make sure it is loaded down like you'll normally have it while fishing. Setting it up without the 500# of gear most of us carry nowadays will throw it way off when you do load it down. Without knowing your current RPM's at wide open throttle and the motor's max RPM range, it's going to be almost impossible to suggest what changes may actually have a positive effect. Right now, the suggestions you'll get will have you chasing unicorns....

posted using Outdoor Hub Campfire


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## nialkc (May 27, 2013)

Make sure the prop has the same size hub as the lower unit. If hub is smaller than llower unit size ,It can do exactly what you are talking about. I borrowed a prop from a friend and I knew it had a smaller diameter.But tried it to see what it did .It behaved fine till about 3500 and fullthrotle. then It would just blow out hope this helps. Nial


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## Gottagofishn (Nov 18, 2009)

Just wondering if you solved this delima?


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## nialkc (May 27, 2013)

I had to use a prop with the correct size hub. The prop I had borrowed did not work. The difference was early engines use the small hub, which is what I borrowed the prop off of. I had a late model Evinrude with the large hub. The props interchanged but will not work properly. Nial


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