Motor upgrade question

[hamms-scooter]

I am looking to upgrade my 1970 25 hp . I am looking for more speed. I have been researching and have found the 50 hp Merc tiller to be called words like proven, bullet proof, powerful. I am looking for just that. I looked at everything from late 70's to late 80's. I saw the years of the hp ratings and when they switched from the 4 cyl smooth engine to a 3 cyl that is supposed to be more powerful. Do any of you have one of these motors being a mercury or a mariner? Looking for advise. Talked to a guy at bait shop today and he had a 81 50 hp merc tiller and said he would buy another one. Let me know if you have one or heard of these motors and what your experience is thanks.

[Gordie]

I have had a couple of the classic 50 mercs it is one of the best 2 cycle motors that mrec ever built IMO. The 4 cyl will troll down all day long and when you crack the throttle they don't load up. I had a couple issues with mine but nothing major I replaced the fuel pumps on both motors and rebuilt carbs on both as well.

Mine were 82-89 year models pretty much the same motor.

I would buy another.

[hamms-scooter]

Thanks for the reply Gordie. What style boat did you have them on? What kind of speed did you get out of it?

[delcecchi]

Back in the day the bee's knees for a walleye fisherman was a 16 foot Lund semi-V with the 50 merc on it. My buddy still has one and it does middle to upper 20's. A hundred pound type person can ski behind it.

[hamms-scooter]

How is it on fuel? The guy I ran into at the bait shop said his sipped gas. My '70 25 hp is tough on fuel. I figure it's from being at wot to get any speed across the lake. It pushes my boat 21 with just me so the 50 that it is rated for should be a huge improvement if I plan to go that route. I was also looking at newer 25 hp but want to get away from being under powered. Re searched the 50 merc last night for hours and I would should like to run one.

[delcecchi]

How is it on fuel? The guy I ran into at the bait shop said his sipped gas. My '70 25 hp is tough on fuel. I figure it's from being at wot to get any speed across the lake. It pushes my boat 21 with just me so the 50 that it is rated for should be a huge improvement if I plan to go that route. I was also looking at newer 25 hp but want to get away from being under powered. Re searched the 50 merc last night for hours and I would should like to run one.

They are a good motor, but a bigger motor will use more gas per hour. You are going faster too but that means you might go farther. But neither motor uses that much gas. Fish all day on a 6 gallon tank, I would venture.

[Surface Tension]

A 70's 25 HP at full throttle will suck about as much gas a 90s 50 Hp Merc but your going to get where your going a lot faster. Performance wise there isn't any comparison.

I have a 90s(just before they quit making them)4 cyl 40 hp Merc and it is a great engine.

Yes they are smooth but IMO not the same hole shot that a twin Rude delivers. Compare the props and you'll see why.

At WOT the 4 cyl will catch and pass.

I'd choose the Merc over a VRO outboard and for sure I'd not touch a OMC that was run at 100/1.

[hamms-scooter]

Thanks for the info guys.

[BoxMN]

Hamms, we have a 82 50hp merc (classic 50 before they it that) and it still is in use (lots!) to this day, tubing, fishing, and duck hunting. They run great, this one has never been in shop excpet for tune ups. The troll great, but know this, they suck gas! I love it, but it totally does like to drink fuel. Part of the price. Not like you will run out of gas going across the lake, but certainly the opposite of today's 4 strokes. I have a merc 60 4 stroke, and holy cow is there is a difference. But other than that, I still love my 82.

Choke the heck out of it first time of the day, and then it will start all day long on one turn of the key. It even starts in spring with one turn, but a long choked turn

Good luck, you will love it. Just bring plenty of gas if you go on the river

[john.wells]

what kind of boat are you running? Check the max outboard HP rating before doing anything to be sure your transom can support it. As a general rule, go with the max rating to get peak performance. A bigger engine would probably help with fuel economy as you will get on plane quicker, and stay there at less throttle.

[hamms-scooter]

I have a 1990 Lowe Lunker v 16 ft. It has a 50 hp rating. I have ran a 15 hp johnson on it and it went 18 mph with just me and now my 1970 25 hp johnny that will do 20 or so. Tired of the underpowered performance. I fish local lakes most often that are only 7 miles long and I rarely run that far without stopping to fish and then I run my minnkota. I ran the length of the lake and back with the wife and kids and burned close to 3 gallons. With no performance..... definately going to max hp. My boat is just a plain resort style with the 4 benches. If i got a 50 I would probably remodel mine with a floor and casting deck to get more weight up front to help with the weight of the 50.

[20lbSloughShark]

I have a 1984 40 hp johnson. It is 2 cylinder 2 stroke, and a terrible motor. Rough idling, not reliable at all, sucks gas like no other. I spent an hour yesterday getting back to the launch with the electric after the stupid fixed jets fouled the sparkplugs twice (i replaced them with the spares and it fouled those too). Get a 4 cylinder if you can, or a 4 stroke. I prefer 2 strokes.

[john.wells]

3 gallons?!?!?! Yep, you would surely benefit with an upgrade. As far as the weight of a 50, you really don't need to worry about bulking up the front to counterbalance it. Your boat is rated for it, so adding the extra weight will only bring down the performance and fuel economy.

[hamms-scooter]

Definately! the 50 hp merc was a 4 cyl in early years and I have read the motor that built mercury up. The later year 50s are 3 cyl. I read that the 4 cyl is very smooth. The 4 stroke would be nice for sure. However that will be down the road for me when I upgrade boat entirely. Looking at the 2 strokes right now.

[hamms-scooter]

Thanks for the advice John. Do you run one of these motors?

[trolloni]

My thoughts, i would stay away from it ,i had one on a 16 ft rebel i bought used off a divorce it blew the head gasket twice 200 each time to fix,a wulfed down 6 gallons of gas like candy!a few times on vacation went through 12 gallons a day!

[john.wells]

I actually own a 90 HP Merc 3 cyl and it sits on a 17 foot Angler Deluxe Lund. It is not a light boat, but the rating for it is 90 HP. It doesn't take much for the engine to get the boat on plane, and I can kick the RPM's down and maintain a comfortable cruising speed. I have an inboard tank that is 17 gallon capacity, and I have cruised all around Mille Lacs for a whole day and still came home with fuel. This is with 3 big guys and a cooler full of beverages and food, a livewell filled with water, etc... The bottom line is that when you underpower anything, you need to give the engine more throttle, and you will never optimize the power to weight ratio, and will kill the engine prematurely.

[john.wells]

I forgot to mention that with the 3 cyls, at least as much as I know, were designed so that the the bottom cylinder delivers just enough fuel for lubrication under 3000 rpm's, but not enough for combustion. This was a fuel saving endeavor, and will run rougher at 3000 or less rpm's than the old 4's because of this.

[hamms-scooter]

Good to know John. I am not worried about the fuel as much because I know I won't have it pinned all day long... I run from spot to spot on these smaller lakes and then the motor is off and I use my transom minnkota. My dad has a 1974 evinrude 85 hp on his 16 ft sylvan and that thing doesn't seem to bad on fuel. I know the 50 would be better. He runs his alot too trolling and wot spot to spot.

[hamms-scooter]

Well last night I did it. I picked up a '83 50 hp mercury tiller with tnt. It starts at the hit of the key and idles down great. The owner installed a new water pump for me just to know where it's at. I am pretty excited to have some power for once. Thanks for the advice guys.

[BoxMN]

You'll love it hamms! Congrats, and enjoy

[hamms-scooter]

Thanks box!

[hamms-scooter]

I ran my new purchase on thursday night and I can say I am very impressed. 34.2 mph on gps in rough water. I love how smooth it is and it idles down great. It doesn't load up when you take off and is fairly quiet compared to my 15 hp and 25 hp. I love this merc 50! Oh yeah you were all so right about the fuel consumption... thirsty bugger but the power it has is a great trade off.

[BoxMN]

Good news Hamms! I knew you'd be happy with it! One other thing I learned, if/when you need new fuel lines/ends make sure to spend the extra $$ and get Merc branded instead of the replacements you find at "stores". For all brands, but I found especially with this motor, the "good" ones work, the plastic cheapies only work for short time before they are leaking air.

Enjoy