Hey guys,
just picked up a 1548 tracker mod v with a 40hp nissan outboard....for $1500! I feel like a kid on christmas morning! Engine fired right up once we'd tinkered with it, it's a '96 two stroke with a four blade prop. Now, the boat's only rated for a 25hp engine but I'm excited to see what excessive horsepower does to a very light boat, what do you guys think? Any estimates of how fast this rig would run/should run? It's a deep hull (16" transom) so I hope this setup works alright.

Porpoise

might as well call it flipper. take a sledge hammer tp the bottom of you boat

i got a 1648 alweld with the square front with an ole 50 merc pushing it i get 39 mph with just me and the gas tank sitting way up in the front and it still porpoises a lil

If you have a 40hp kicker how big is your main motor?

Put your gas tank, battery, and everything else in the front. If the motor dont have a hydrofoil stabilizer on it get one and have fun. I ran a 40hp on a 1236 rivited lowe boat for about 2 weeks until I beat a crack in the aluminum from opening it up in rough water and trying to bounce my buddy out of the boat. Brace your transom and hold on tight.

so to curb any porpoise the solution is weight up front? Should be able to take it out here soon, things have been pretty warm out here in Utah. The motor does have a stabilizer on the lower unit, what does that actually do?
Also, why do they have HP ratings for boats? is it a weight consideration or that that transom can't handle the thrust?

Also if you wanted to get more top end get a good 3 blade. The 4 blade is good for getting a heavy boat on plane quicker. Im sure that 40 will have no problem getting that little boat on plane quick fast and in a hurry.

like you said, I doubt top end will be the issue I have Think it'll troll as low as 2mph?

At just idle it should be close to 2 mph. If not you can put a trolling plate on it to slow it down, or just troll in reverse.

You will be fine. The first boat I purchased was the stupidest purchase I ever made. I bought a 15 ft x48 Alweld Avenger with a freaking 2stroke 90HP merc. Dont ask why, I still dont know what I was thinking at the time. Boat could not handle the HP and weight and eventually the boat started cracking from side to side about 4ft from the transom. Even after a professional welding/fabrication job and braces added in, it re cracked at the welds the next time I took it in rough water. I ended up trashing the 15x48 and putting the 90 on a 19ft Carolina Skiff.. live and learn the hard way. Im sure you will have a slight porpoise effect to deal with.

ha! bet that sucker MOVED though! you could pull a tuber pulling a wakeboarder with a setup like that!

If you move your gas tank and battery up front, you will lose alot of top end speed but it will plane off a millisecond quicker with one person in the boat. gonna plane fast by yourself. Im assuming its a tiller setup. not sure why it's only rated for 25 as every 48" i know is rated for a 40. You're certainly not overpowering it.
My main boat is a 1548 War Eagle with a Tohatsu Mega (40hp) 2 stroke 3 cyl. Tohatsus and Nissans are the exact same motor in that year. Runs 40 with nothing in it but me an 1/2 tank of gas. I have CMC PT 130 tilt and trim though. Same motor ran 36 when bolted to my 1542 war eagle with no trim. My gas tank is generally in front of me as I have rear pods. You need to drop the 4 blade and buy a Turbo Hot Shot 13pitch. Might get by with a 14 if you want a little more top end.
No porpoising by the way with tilt trim and you will have no porpoising if you have fixed trim and you put the pin in the right spot. HOpe that helps.

forgot to say that you really need to pay attention to where the motor is bolted on the transom. If you only have a 16" transom, I would guess that the cavitation plate is going to be slightly too deep in relation to the bottom of the boat. Since i have the same motor, i've found it helpful to play with the orientation a bit to make sure the cavitation plate is even or 1/2 higher than the bottom. be careful though because if its a fixed trim with a pin and you move the motor too high, it's very fast on a straight away but uncontrollable in a turn with heavy cavitation.

Here's a couple pics. One of the things I worry about is that its a long shaft motor, so the prop sits well below the boat (as well as the cav plate) What is that going to do to the boat?
lectricduck, the last thing I want is this thing to go faster! I'm thinking the four blade prop will be perfect for carrying me and a bunch of stuff or people, which is usually what my duck hunting and fishing ends up being, I never fish or hunt alone. What's the CMC PT 130? A hydraulic trim setup?

It's not going to be as fast you think. Motor is a 40C (2cyl) instead of a 40D (3cyl). Still a great motor though. Motor already has a whale tail bolted to cavitation plate. Motor hanging deep in the water is going to prevent it from performing properly. Extra drag, wont go as shallow, hits stuff easier, and most importantly wont get you the proper trim angle when on plane.
I had the same thing on my old 1542 and just built a spacer plate the bolted to the transom and through the motor that raised it up 4 inches. The right way to do it would be to take the boat to a local aluminum fab shop and permanently weld a spacer to raise the motor if you don't want to go the cmc route.
I have this cmc: http://cook-mfg.net/cart/index.php?main ... cbafeba4fa

Sorry, dont know how to hyperlink. You could probably get by with the PT35 since its a 40C. Similar weight to a mercury 25. I really like my tilt trim. I have a switch on the boat to operate and also a switch wired into my spotlight so you never let off the throttle.

how far does the whale tail hang under the boat in inches?

If the cav plate is wayy to low below the boat you might want to look at a mini jacker jack plate. T & h marine makes them and you can find them for under 70$ online. You can raise the otor the right height and get the best performance. If I were you id lower that back seat because the higher you get while riding the more tippy a boat gets.

I already took the pedestal off the back seat, no idea why someone did that. I've already got a big back deck so using a jack plate would set it even further back.....maybe I just find another motor and sell this one for almost what I bought the boat for?
I'm keeping it at a buddy's house for now so I'm not sure how low that cav plate hangs, my guess is at least 4" or so. I'm sure the CMC is nice but thats a lot of money for this poor college student! Wife's already a little peeved that I bought the thing and am now sinking more money into fixing it up! Maybe I just run it as is unless I can find a short shaft for a good price

i'd keep the motor if I were you. It's not that big a deal to raise the motor up at all with the jack plate. the 70.00 jack plate that WAD suggested is a helluva lot cheaper than messin with getting a motor. Tohatsus/nissans have really short tillers. I bought a custom tiller extension out of FL that is awesome. I added 18" to my factory handle. Makes it perfect. I don't think you'd need one that long for yours though.
You're talking about $200.00 tops to make the boat awesome. http://www.strongarmproducts.com/ is the link for the tiller extension.

Thanks for the information! Hey, do you know how to drop the lower unit out of a nissan to check the impeller? Looks like there's a little pin in the gear shift rod that prevents it from dropping once I get the bolts undone but I'm not sure if that's the best way to do it.

Next on the list of things to do is put in a deck (the ribs are 1.5" tall and annoying to walk across), boxes for seats and a small deck extension. Maybe i'll start a new thread and see what people have done for custom seating in their boats...

I've never takin the impeller out of a 40C but on a 40D, you un bolt the lower unit bolts (10mm I think).
The shifter linkage is visable but you have to move the shifter lefter around to be able to view a VERY small pin that connects the lower link to the top linkage. You have to push that out and you should do that before you unbolt the lower housing.
Once the lower unit is sitting on the ground, you should see 4 more 10mm bolts that and a silver looking cap. unbolt that and start removing the gaskets and small pie shaped seat carefully. You'lll see the impeller in its housing. New ones are around 35 on Nissans and like 100 if you want the whole kit to include new gaskets, housings, and rubber impeller. The pain is getting the pie shaped seat lined up when you put it all back together. Its easy but you really need 2 people so that 1 can hold the lower unit and 1 can eyeball the seat and line it up. No seat means no water pumpage. Hope that helps

Thats perfect! thank ye kindly

[youtube]http://www.youtube.com/watch?v=n68sb7w-3Hw[/youtube]

This video is for a Yamaha 25 four stroke but the principals are the same for about all motors I have worked on. The main difference I have noticed between motors is the shift linkage. For example, on my 9.9 Johnson you have to drop the lower unit about an inch to access the shift linkage and it is held together in a set screw type fashion. But the tips and techniques shown on the pump installation, like using a dab of grease to hold the key in place are solid, universal tips.

Great, Thanks again!