How to convert Mariner 50HP 2 stroke to 60HP (1991-1997) I've got a donor engine!

[GreedyMuffin]

Hi!

Recently I purchased a 50HP Mariner 2 stroke 96-97 mod. Been serviced good, had to change the impeller, every bolt was greased up so an easy job!

Anyhow, a couple of days ago I got my hands on a complete Mariner 60HP 1992 mod. It was purchased in 1992 for the Barcelona Olympic, so it got some history to it. One owner. Worked before they put it away a couple of years ago. They just purchased a brand new engine since the carbs were leaking. Didn't want to invest money nor time to it. Payed less than 150 USD. The seller lived good, so he just wanted to get rid of it.

Anyhow, I assume the 50HP is in a better condition even if I manage to get that 60HP working. Both got trim/tilt so basically I've got alot of parts for a little sum.

I really want to convert my 50, to a 60 though. I've got a "rare" (under one hundrer produced) old Norwegian boat (As I live in Norway) "Rana 16 line". One heck of a heavy boat from the 70s. Mine is a 1970 model. 375KG, 4.75M long and 1.98M width. So It's quite heavy for It's size, built like a tank. ^^

Now, some questions!

1. The 60HP got it's oil injection system turned off, wondering if I should do the same on my 50HP?

2. What should the PSI be at? My current 50HP got 112-115-114 or something on the different cylinders. Is that OK? They are quite lean on the mix, and it was on a coldstart. So I reckon It's within the normal range?

3. What parts do I need to transfer to the 50HP from the 60HP?

Some say the engine block got some bored out a bigger exhaust, so it won't be worth it, other say just the carbs!?

I need a definitiv answer before I take the time to rebuild the 60HP carbs.

Thank you!
Sincerely
Christian Thorkildsen

 

[GreedyMuffin]

A friendly bump!

 

[ondarvr]

Pull up the parts list for each one and compare each part number, it's the only way to do it.

 

[GreedyMuffin]

Hi!

From this thread it says it's only the carbs. http://forums.iboats.com/forum/engi...er-outboards/381860-50hp-vs-60hp-litttle-help

But I'm not sure if they mean the 59CI modell, or the 51CI modell that I've got. (Afaik they introduced the 59IC on the last year of the 51IC).

Will try to see if i find the part list online for the engines. It's 00:25 AM, so will look it up tomorrow!

If anyone knows, it would be great to know. Will try to call a Mercury mechanic on Monday. He might have the answers I need.

 

[ondarvr]

The internet works at 00:25 am, at least it will in the parents basement, so you can still find it. LOL

Most of time you will get both yes's and no's to this type of question, each will be guesses, sometimes based on little knowledge or fact. The parts list gives you the exact answer quickly.

 

[GreedyMuffin]

Hehe, was more towards me being tired. ^^

Will look through the manual(s) if i can find em!

Thanks for your help!

 

[ondarvr]

At that time of night my eyes don't even focus.

 

[GreedyMuffin]

I'm 16 and my sleeping rhythm is completely ruined due summer vacation here in Norway, so I feel confident enough to do it lol. ^^

Will look more on the parts list tomorrow on the engines itself as I've got both here, home!

 

[GreedyMuffin]

I think I found the answer?

https://www.marineengine.com/parts/mercury-outboard-parts/50-3-cyl/0a721308-up-can/cylinder-block

865-8362A10

Versus

865-8362A11

Wellwell.. I don't know if they are different because it's another engine, or if it's another type of block. :/

 

[GreedyMuffin]

Wait a minute!

Here it says..
811209A93 POWERHEAD (1 required per assembly)

PH 50/60 3CYL O NLA 811209T93 PH 50/60 3CYL O NLA

https://www.*****************/parts/m...-crankcase-140

Mod EDIT: Iboats is an online retailer and competitor sites are blocked.​

Same enigne block? Leaving out the 43 (50HP carbs) and the 44 (60HP carbs) the only difference?

Got an email from "RavnsGarage". Very profesional Norwegian overhaul/Mechanic shop. They said the parts are the same if both motors are from the same engine familiy 1991-1997.

But when I search for part they often come up with 50/60HP 1991-1993 and 50/60HP 1994-1997. Why is that? The engine I guess its the same?

Sorry for a bad post, messy and such. Going to bed now and picking up this again tomorrow! Thank you for your help Ondarvr!!

 

[Faztbullet]

Difference is year model cubic inches...early motors are 2.955 bore and later are 2.993 bore

 

[GreedyMuffin]

Thank you!

Does that mean my engine can't use parts from the 92 version? Like carbs, lowerunit etc?

They look the same, can't tell the difference between the two. The only difference gotta be the engineblock/powerhead?

 

[Faztbullet]

Only difference is: cylinder block,carbs,upper main seal and brg and t-stat as small bore use a 143 degree and big bore use a 120 degree. You might get carbs to work but high speed jetting will be trial and error

 

[GreedyMuffin]

High speed jetting?

Please explain if you can. (As English is faar from being my first language.)

 

[GreedyMuffin]

Hi again!

Yesterday i installed the 60 carbs, she was a little smokey at first since we gave her a little too much gas. but shes running good now.

Bought a tachometer as well, waiting on that to arrive so i can test my 15P steelprop, 14P alu and 13P alu. I reckon the 13P is the best match for my boat/engine and running 14P on the 50 was the reason i lost a few knots.

Wondering if i should take the carbs off and just clean them, once and for all. :hmm:

I don't know if that makes a difference, but i measured the intake to the valves and such, exactly the same length/width on the 50 as it was on the 60.

 

[GreedyMuffin]

Clanead the carbs as it would only run on two cylinders on idle, was also very slow on throttle respons, and didnt not run very clean on idle. Shaking and whatnot.

Cleaned the carbs with vinegar, then gasoline, then another round with gasoline. The middle sylinder was pretty clogged up, hence why it was only running on two on idle.

Now it runs perfectly. Measured the reed vents when i took of my carbs and compared them to the 60HP, exactly the same.

Gonna test my props when i get my rpm gauge.

It's fun for me to learn, since I'm only 16, I haven't really been that mechanic, it's been more about Pcs, watercooling, overclocking, folding@home etc.

 

[ondarvr]

Sounds like great progress.

 

[GreedyMuffin]

Yep!

My thermostat kit is coming today, figured it I might just change that as well since I'm already messing with the engine. Then the gearoil, impeller and thermostat is replaced, and the carbs are clean. Nothing more i can do, nor need to i guess. (If you recommend something, please give suggestions!)

I'm gonna install my RPG gauge as well. Really looking forward to test the props! :-D

 

[GreedyMuffin]

Installed everything. The engine is running to high on idle, around 1000 RPM due the "hammer" (?) is not going fully back, so need to grease that up.

The thermostat is replaced, with all that is to it, It was "leaking" out water, an indication that the sealant is bad. It was cooling the engine to good as well. The tell tail was too cold, streaming out cold water on Idle instead of somewhat warmer water.

Will update on the prop or if I need some help. ^^

 

[GreedyMuffin]

Got back from RavnsGarage that they were mistaken. The 50HP got a smaller exhaust. And that's why the top speed was the same as with the 50HP carbs.

Same block, different exhaust.