4 stroke merc 40 into 60Hp mod

[johnmpcny]

Read on older posts on many families of outboards you can switch a few things and gain extra HP. I have 40 hp 4 stroke Command Thrust on my sun tracker 18 pontoon. A newer 2019. The same steps are true with the 50hp to 60 mod.

Reading the manual you take out restrictor 8831482 RESTRICTOR 40 Horsepower/Non Jet
Then you replace ECM 8M0120422 ECM Engine Control Module - 40 HP with
4 Cyl with 8M0120419 ECM Engine Control Module - 60 HP Note on the manual the only parts different from 40 50 and 60 are these. (BTW lots of different years manuals on the site so check your serial/part number)

Prop may change up from stock prop up 1-2 in pitch or not depending on rpm range you get.

Was told simply removing the restrictor plate will improve performance but may raise rpm too high. So outside running the motor harder and at a higher RPM limit may reduce the life (no more than any 60hp vs 40) of course it also voids the warranty. Any other reason not to? Interesting the list price is about a 40 vs 60 is $1000-$1400 difference,

I bet I can recoup $300-400 selling the 40 ecm on ebay.

ECM Engine Control Module - 60 HP 4 Cyl​

8M0120419​

by Mercury

$841.64 7% OFF

$782.73

 

[cmounit95]

Did you end up changing out the ECU and restrictor plate? I have a boat on order that should be here in a month or so with a new mercury 50hp efi I would like to try this on. I found a 60hp ECU online I am going to buy if it went ok for you.

 

[johnmpcny]

Not yet our boating season just started I am going to wait to get some time in to make sure the motor is running well. (about 8 hours on it so far) My local mechanic says if it going to be a issue they show right off and wait to make sure any bugs are worked out.

 

[pete307]

I'm getting ready to do the same on my 2018 Merc 50 HP. I know it's not a big increase but want to tweak it to get the most out of my motor. Can either of you post an update on how your conversion went?

 

[pete307]

I went ahead and pulled the rigger on upgrading my 2018 50hp EFI to a 60hp EFI. $750 for the new ECM and a couple of hours of labor later I now have a 60!! Just replaced the ECM and took out the restrictor plate in the intake manifold. Gained about 300 RPM. Had to increase the prop pitch from a 12 stainless to a 13 stainless. Perfect redline now at 6000 rpm and gained about 2 mph. Better hole shot too. I was more concerned about loading as I do a lot of running around in the north woods and need to haul all my camp gear and still be able to plane. I can use the 13 stainless prop for everyday stuff and go down to the 12 for carrying the big loads. I know it doesn't sound like much but the tweak was worth it to me. It irritates me that my boat was only rated for a 50hp when I would have gladly paid the extra $$ for a 60 right from the start. Same motor, same weight as the 50 but can't understand why the boat (Lund Rebel) wasn't rated for a 60 in the first place. The boat really performs nicely now and I also highly recommend going with a stainless 4-blade vs the aluminum. Less slip and much better cornering.

 

[USA_boater]

I went ahead and pulled the rigger on upgrading my 2018 50hp EFI to a 60hp EFI. $750 for the new ECM and a couple of hours of labor later I now have a 60!! Just replaced the ECM and took out the restrictor plate in the intake manifold. Gained about 300 RPM. Had to increase the prop pitch from a 12 stainless to a 13 stainless. Perfect redline now at 6000 rpm and gained about 2 mph. Better hole shot too. I was more concerned about loading as I do a lot of running around in the north woods and need to haul all my camp gear and still be able to plane. I can use the 13 stainless prop for everyday stuff and go down to the 12 for carrying the big loads. I know it doesn't sound like much but the tweak was worth it to me. It irritates me that my boat was only rated for a 50hp when I would have gladly paid the extra $$ for a 60 right from the start. Same motor, same weight as the 50 but can't understand why the boat (Lund Rebel) wasn't rated for a 60 in the first place. The boat really performs nicely now and I also highly recommend going with a stainless 4-blade vs the aluminum. Less slip and much better cornering.

Can you share what year your motor is and what part number ECU you went with??? I have a 2019 (motor might even be a 2018) and I am interested in doing this mod. Also, did you ever run it without the restriction ring while using the 50hp ECU? I'm wondering how the OME computer would react if this was tried? Thanks!

 

[johnmpcny]

Can you share what year your motor is and what part number ECU you went with??? I have a 2019 (motor might even be a 2018) and I am interested in doing this mod. Also, did you ever run it without the restriction ring while using the 50hp ECU? I'm wondering how the OME computer would react if this was tried? Thanks!

I am waiting to do this until I am off of the factory warranty. I was told you may gain some just removing the restrictor and org ECU "may relearn" the new fuel flow. But to get the most you must change ECU and remove it.

 

[pete307]

I am waiting to do this until I am off of the factory warranty. I was told you may gain some just removing the restrictor and org ECU "may relearn" the new fuel flow. But to get the most you must change ECU and remove it.

I didn't even try with just removing the restrictor plate. I wanted to do it right so I also installed the ECU #8M0168149. There isn't a lot to be gained here so wanted to get everything I could. It made a noticeable difference and I'm happy with it.

 

[pete307]

My motor was a 2018

 

[Faztbullet]

ECU is dumb...will not "relearn"

 

[USA_boater]

I didn't even try with just removing the restrictor plate. I wanted to do it right so I also installed the ECU #8M0168149. There isn't a lot to be gained here so wanted to get everything I could. It made a noticeable difference and I'm happy with it.

I appreciate the reply! I am seeing two different part numbers. The one you mentioned above AND 8M0120419. Can you or anyone else comment on why two part numbers? Could one be superceded? Also, where did you get your ECU and about how much did it cost? Thx again!

EDIT: did you have to change the prop??? I have the OEM 50hp black max (can't remember pitch) and I also bought a spitfire 4 blade in the same pitch as the factory prop. I am hoping I will be able to use one of the two? How much top-end did you gain with the jump in HP?

 

[ahicks]

News flash. If before and after rpm numbers don't easily show it (say a 500 rpm increase minimum), and the motor won't pull a bigger prop, it's NOT making any more power than you started with. No "if" to it....

Anything else is due to your imagination/wishful thinking....

 

[pete307]

My estimate of a 300 rpm increase was on the conservative side. It was a little more than that. I had to increase the pitch by 1" to keep the WOT at 6000. I'm running a 4 blade stainless 13" now. Top speed increased by 2 -3 MPH. Hole shot feels better. News Flash! It wasn't my imagination. It was actual test results. And I can feel the difference. The ECM I put was the latest one, it superceded the older one. It was about $800 (If you can find one)

 

[raczekp1]

here in Poland is a workshop and they have axpirience to uppgrade your ecm.
you can email them and ask. tey did thi uppgrade flash ecm on mercury outboard 40 to 60 hp
https://pl-pl.facebook.com/pages/category/Automotive-Consultant/MotoStrefa-1651254311778688/

 

[USA_boater]

My estimate of a 300 rpm increase was on the conservative side. It was a little more than that. I had to increase the pitch by 1" to keep the WOT at 6000. I'm running a 4 blade stainless 13" now. Top speed increased by 2 -3 MPH. Hole shot feels better. News Flash! It wasn't my imagination. It was actual test results. And I can feel the difference. The ECM I put was the latest one, it superceded the older one. It was about $800 (If you can find one)

I'm pretty sure my boat came with a 13 pitch on the 50hp and I know for sure the spitfire I bought is a 13 so maybe I'd be fine if I used the 4 blade 13. If running the 3 blade and only me and half tank of gas, I can turn 6000rpm, but I boat is loaded down, then a little less so since I usually run heavy, the increase in rpm 3-400 would be great. I assume if the motor over revs the engine would go into some sort of protective mode?

 

[pete307]

Update to my configuration above. I went down to a 12 pitch 4-Blade stainless prop. Stainless doesn't flex like aluminum so my 12 pitch stainless performs like a 13 pitch aluminum. Great hole shot and WOT at 6000 gives me about 35 mph, whereas I used to get about 31 mph at 6000 with an aluminum prop. Changing the ECM, taking out air restrictor plate, and changing to 12 pitch stainless prop made a world of difference!!! I like it!!!