1979 basstracker II and I'm looking to put a 15hp 4stroke Mercury on her

I'm looking to put a brand-new 2006 15 hp four stroke Mercury on my 79 Basstracker II. Does anyone know if that will be to small? It came with 40hp 2 stoke. But I don't want to put another 2 stroke back on and the newer 4 strokes all weigh so much. Any thoughts?

What are you using the boat for? Rivers, ponds, small lakes? Is the boat set up for tiller or remote steering? Whats the weight of the boat loaded?

I live in St. Paul, Mn so I'll be on lots of different waters mainly the Mississippi(I'm about 10 minutes to 4 different river landings) by my self usually but will have the girlfriend with once in a while. The hull weight is 575. But I would say it's probably closer to 600-650lbs. I replaced floor and removed the livewell/seats. Used 3/4 plywood. The 2006 15el Mercury I'm looking at is 111lbs.

This what is looks like

http://bassfishingarchives.com/retro-ads/the-beginning-of-packaged-boats

Minimum of a 30hp n my book due to current flow.......

agree on a minimum of a 30 and would go with a 40.....horsepower is a safety factor in certain conditions....too little is as bad as too much...i have a friend running a 50 evinrude on a old tracker like that...perfect match...

you will not be happy with a 15 for long on this boat...

Thanks guys. I had some serious doubts about it being enough. The only reason I thouught It might work is because basstracker puts a 20hp 4s Mercury on the 2014 version of my boat. I've been searching for something new but I only have $2k to work with. The new 2006 Mercury 15hp was the best I came up with new.

I agree with a minimum of 30 hp especially with being on a river with strong current. A 15 hp would prob push it around a pond or tiny lake but youd never plain the boat. Is there something wrong with the 40 hp it came with or are you just looking to upgrade? I wouldn't be afraid to get a newer 2 stroke, they have came along way with the technology especially if you get direct fuel injection

i ran a 18 in the late 60,s on a 14 foot johnboat...it was 2 cycle of course...todays 15 will be close to that because they measure at the prop instead of the head...i dont think i ever knew the weight but it was light...i put a wheel in it and it would plane and cadillac around the bayous pretty good...slow but was ok...in todays environment with the hi powered bass boats out there it would be suicidal to run it though in a lot of places..
i dont know what the river is like up there...i live in baton rouge,la. and i would not ride anything smaller than a ferry here...
i get the impression that this is maybe you first boat...if you go with the 15, or any motor for that matter, i would recommend you put a wheel in it...you have better control and it would move your weight forward some and would come up on a plane better...if you go with a tiller make sure the friction is adjusted where the boat will still run true when you take your hand off the handle..

where are you coming up with a new 2006 motor?

some advice from a 76 year old man...before you get married go buy a new boat and motor and finance it for 99 years if you have to....if you dont you will be busy buying couches and chit like that for 10 years without a decent boat...
Tim decided to tie the knot with his long time girlfriend. One evening, after the honeymoon,
he was assembling some loads for an upcoming hunt.
His wife was standing there at the bench watching him. After along period of silence she
finally speaks. "Honey, I've been thinking, now that we are married I think it's time you quit
hunting, shooting, hand-loading, and fishing. Maybe you should sell your guns and boat."
Tim gets this horrified look on his face.
She says, "Darling, what's wrong?"
”There for a minute you were sounding like my ex-wife.”
"Ex wife!" she screams, "I didn't know you were married before!"
”I wasn't!“

I've been looking at 2 strokes but was worried about noise and smoke. My 1979 40 merc was stinky and loud when it was running in both cylinders. It really pushed the boat along for a few days till started acting up.

It does have a wheel. It's not a big lake boat unless under ideal conditions. I think we have about a 4-8mph current the river depending on where I go. The displacement between a 15 and a 20hp is about 2 cubic inches if I'm not mistaken. Also the newer basstrackers are heavier than my older model. If I could get 20 mph with 2 guys I'd be happy.

I got lucky. I wanted a 20 but couldn't find anything with the right price and age. The guy said its brand new with 30 day warranty.

I found a 2013 40elpt 4 stroke but It weighs 216 lbs. I'm now worried about being overpowered and overweight. Has anyone put this big a motor a vessel of my size. It's rated for a 40hp but I suspect they meant 2 stroke any thoughts anyone

Hey Papyson I have counted the 15el out. I have now found a 2014 40hp 4stroke merc and now I have the opposite worries. The motor will be 216 lbs that's 60 lbs more than the original 40hp and 30lbs Heavier than the 60hp equivalent weight of what it's rated for. My transom is in great shape no cracks. Once in a lifetime(maybe) decision. I'm gonna think about it for another day. Thanks for any reply.

It's not the weight on the transom that is a great concern. If the transom is sound it will hold that 216 pounds going "straight down".

The motor "pushes" against the transom to get her going (plus every bit of weight on board) forward.

There is no direct equation to convert horse to thrust but in general each horsepower produces about 26 or 27 pounds of thrust. So if you open up a 40 horse motor it's (potentially) putting almost 1100 pounds of "thrust" on the transom which makes the motor weight look like chicken feed in comparison. It's that torque/thrust that is trying to "pry" the transom "off the boat" from the top of the transom as the prop literally tries to "crawl" under the boat.

The max rating is based on that, not necessarily the weight of the motor.

What the heavier motor "might do" is leave the hull a little unbalanced (more weight over the transom - think teeter-totter).

When the 4 strokes first became prevalent one particular model of Lund went from a 150 horse rating to 115. When I inquired I was told by the Lund rep that they were in the process of changing the balance of the hull for the new model but until they did the weight of a 115 4S was close to that of a 150 2S which resulted in the max hp change.

On an older model boat, if it was rated for 40 horses you can run a 40 4S you just may have to move some "non-static" weight a little forward to keep the hull balanced properly, but otherwise, the transom can absolutely "hold" the motor. It could probably hold a 600 pound 350 Yami. The problem would occur if you hit the throttle and all that thrust ripped the transom from the boat.

Thank you sir. Here's a link below to that first merc I was looking at. Killer deal but I would have had buyers remorse the next I went fishing with my brother and he was running circles around me. I'm going with the 40hp Mercury. Thanks again when I get on the river I'll report back with how things turned out.

Well I ended up with a 2010 40hp Mercury with 14.4 hrs. She goes great. I had some slippage if I gunned it to hard during planing. But other than that it was great. I currently have a 10.5"/11p prop. It went 30 mph at 5750 rpm's and I had plenty of throttle left. I didn't go past 5800rpm out of fear of over reving also I had 10-15mph winds on the river. I went on mercury's site and it recommended a 10.5/14p so think I'll find one. What do you know about props? If I'm not mistaken each degree of pitch changes 250 rpm's is that true? Thanks for your advice.

Ok prop search update. I got my hands on a 10.5/14p solas 4 blade from a buddy. It had awesome get up and go but my top end was drastically affected. My max speed was 29ish but my rpms were only going to 5100 at full throttle. I decided on trying a 10.8/12p 4 blade solas I'll report back with a performance report.

Hello motorboaters. Prop update post. I ordered and received my new 4 blade solas 10.8/12 pitch prop the other day and took her for a spin. I had the girlfriend with me and the prop worked perfectly. It had great get up and go with a top speed of 32 mph going down river with a tail wind. I love how smooth it runs when trolling compared to the 3 blade. Thanks for all the support and good luck to anyone reading this.