Evinrude 3 cylinder 56.1 cu in 50hp?

[sutor623]

Hey fellas,

Long time no see. I was wondering if you guys knew what years OMC was making the 56.1cu in block in the 50hp range?

Reason I ask is I am building a console steer jet outboard boat and I have a 50HP tag rating on the placard. I would like to get the big block 50 and put a jet foot on it. I may also, down the road re-carb it for 70hp. Thanks guys!!

 

[ondarvr]

What type of boat? The 50 may not even get it on plane with a pump.

 

[flyingscott]

IMHO Buy the 70 hp right away and forget about a 50. The reason is by the time you put the pump on the 70 hp it will have a pump rating of about 50 anyways, and the 50 will be about 30. The 70 hp motor will be much easier to find and and changing the 50 hp to a 70 is not that easy . This advice only applies as long as a jet pump is put on the motor not if you keep it prop driven set-up.

 

[sutor623]

So, the current motor (that I just sold) was a 25/20 mercury jet, tiller steer. It is on an all welded 1648 polar kraft boat. When I had wood floors, 2 people, full cooler, rods, battery and 10 gallon livewell the boat planed out and stayed on plane. It would only reach 17mph but the motor ran strong and kept us on step. The issue that I had is that we would sometimes run through 6-8" of water and the person up front had to tell me where rocks were. I felt like I was running blind.

I decided to put a center console up front so that I can see whats ahead. Since I am going console steer I decided to sell the tiller motor rather than convert it. So any power over what I had will be nice.

Issue is that the transom tag says 50hp. I can get a 75/50 jet from the factory because it is 50hp on the serial number. My concern is if I get a 70+hp motor and convert it to jet, it will still only be 50hp from the pump, but the serial number will say 70hp. I dont want issues with insurance or lawyers etc. Factory jets in good shape are hard to find. All the new ones are 4 strokes and really sink the tail end of the boat down. A bad thing to happen in 12" or less of water!!!

 

[ondarvr]

The insurance/lawyer thing is a bit over hyped, but local laws can limit HP. Check to see if local regulations limit you.

 

[sutor623]

We have no HP limits on the waters that I fish. I seen a lot of people on here get flamed for overpowering their rigs. I have a hard time believing that a .100 gauge welded polarkraft from 2000 has a 50hp transom tag on it, but so be it.....

 

[ondarvr]

They do get flamed, but the insurance and Coast Gaurd side of that argument don't hold up, the safety and local regulations do. Lots of john boats around here with jets on them, my friend has a 100HP merc pump on his 16 footer, my 15' has a 90 and an 8(not a john boat). Just depends on the boat/motor combo. John boats typically have the transom raised and a couple of braces added with bigger jets, you need to make it 25 inches high for a pump.

 

[sutor623]

Yes sir you are correct about the height. The motor I just took off there was a short shaft jet (15") and it sat on there perfectly if I put it up about an inch high.

 

[Faztbullet]

Find a mid 90's 50hp short shaft, add 70hp carbs and jet and your good to go....I have a duck hunter with a 20ft Lowe boat with 150 Merc...nicked named SS Nimitz

 

[sutor623]

^Thats awesome!! So the mid 90's 50hp's are three cylinder engines?

I was looking at the merc 50hp vs the rude 50hp 2 strokes. The 2 cyl 50's (by far the most common) came in a 44 cu in engine. Lots of the Merc 50's come in 59 cu in!!

 

[Watermann]

I believe the 70 goes to 3 cyl and it has a large gear case whereas the 50 is a 2cyl and small gear case.

 

[flyingscott]

I believe the 70 goes to 3 cyl and it has a large gear case whereas the 50 is a 2cyl and small gear case.

​No in the early 90s evinrude started building a 3 cylinder 50 hp on the 56 CID block.

 

[sutor623]

​No in the early 90s evinrude started building a 3 cylinder 50 hp on the 56 CID block.

Thats what Im talkin about! Did they make this in the two stroke carbureted engine? I know I have seen a 2003 3 cylinder johnson but it is a 4 stroke.

 

[ondarvr]

Mid 90's, look at the 95' models, yes 2 strokes. I didn't look to see if the block was the same, this will let you know if you can actually get 70hp out the 50hp block.

 

[flyingscott]

Thats what Im talkin about! Did they make this in the two stroke carbureted engine? I know I have seen a 2003 3 cylinder johnson but it is a 4 stroke.

Yes in the early 90s OMC redesigned the ports on the 56 CID block and the 50 hp I believe was the first to be built on it. They are not the most common motors at least around me. I see many,many more 60/70 hp motors. You also want to make sure the cooling updates have been done to it.

 

[Watermann]

Found a pic of the service manual for them, so I guess so!

 

[sutor623]

^ Thats awesome!!

The 50 3 cylinders are a rare breed around here..............

 

[racerone]

But you want the 70 hp model as HP is lost in the pump.-----------70 hp into a pump = 50 usable hp out the pump.

 

[Watermann]

^^^ Wow a jet pump eats that much HP?

 

[racerone]

Yes it does.---150 HP V-6 is rated at 105 hp of useable power from the pump.---Just the laws of physics.