Thanks Tony, straight forward enough but not cheap I'm afraid. Hopefully worth it as I can move back up to my 10" prop again now - less revs more cruise speed!
Thanks mate much appreciated. Turned out to be painless, and checking the key parts in the parts catalogue confirmed they're the same engine. Interestingly a mate with a Merc Mariner confirmed under the cowl is identical to my Tohatsu!
just bought a 2011 Mercury 15 and was reading the servie manual. The Manual is for 15 and 20 I was like oh I'm curious how much bigger the bore or stroke is on the 20.... looking at the specs everything was IDENTICAL b/w 15 and 20. I then figured this must be a manufactuer using an ECU to limit power like BMW and Porsche do which is easily flashable to get much more power. Then I remembered all the small Mercury outboards are just Tohatsu's.... found you on RUclips and then I see you holding a QUICKSILVER aka Mercury parts division box. I'm totally doing this to mine, what is the part number on the box?
Hey glad this was of some help to you. The performance improvement was well worth it in my opinion! Here's the link to the ebay listing I used, which includes Merc and Tohatsu part numbers! www.ebay.co.uk/itm/204484940612
9.9, 15 and 20 EFIs are the same engines with different ECUs and presence of a restrictor plate. They share a parts catalogue aside from those. All weighing in at approx 44kg dry.
Hi Steve, thanks. I bought my 15hp during covid and it was one of the only engines available in the UK at the time - which would also ship to the Isle of Man. A costly upgrade but sometimes you've just got to bite the bullet!
I know what you mean. I also had to wait a while to get my Tohatsu 20hp. Are you pleased with your tohatsu, I got mine in December 2022 and have done 40hrs so for. All tucked away for winter now. Enjoy your channel 👍
Thanks mate. Yes I absolutely love my Tohatsu - a solid piece of kit which gets used year round. The pre-winter service gets her ready for the cold weather
Hi and greetings from Germany. This is exactly what I was looking for. Great video and explanation. Unfortunately your links to the ecm do not work for me. Can you please tell me what part number the ecm has?
Good day! Thank you for posting this video, I got a 2023 9.9 on dealer recommendation for a smaller boat(I’m not a big boater I’m new to it) and could use more power. I will be doing this soon. Can you provide a link for the ECU? My understanding is the 9.9 is the same as 15 and 20. What prop did you upgrade to? Thank you for the help!
Hello! So happy you've found this useful. The part number listed on the eBay item I purchased is: Mercury: 8M0135817 & Tohatsu: 3RS-06401. The original listing is no longer available I'm afraid so I can't share the link. Good luck!
Is it not possible to get the ECM remapped rather than buy a new one that looked very expensive. I wonder what would happen if you just removed the restrict or plate
I did research a remap and it is possible, but i was put off in case it bricked it. The only widely advertised option I could find was someone in Australia, oddly. I'm sure others can do it. This way, I have a 15 and a 20 ECU. When I sell the engine I csn include the buyers preference, and then sell the other still.
Removing only the restrictor plate would force the engine into a limp low rpm mode. I have seen videos of some boring the restrictor out a tiny bit, but not worth the risk in my opinion - it's important those injectors know how to correctly operate given the air flow
Just removing the restricter plate is all you need to do. It doesn't go into limp mode, it runs like a scalded dog! In my case with the motor on a 15,6 gheenoe classic weighing 245 lbs plus gear I had to go from the 10 pitch prop to 13 pitch to pull rpms down to 5900 rpms with a gain of 3 mph.
Hi guys, I did the restrictor removal only yesterday. Mine went into limp mode but I could defintely feel the extra power before it did. Guessing low oil pressure from possibly over revving. Turned it off and re-started and it was fine again. Having the extra power was way better.
Great video mate. I am currently running the 15hp Mercury 4 stroke. Would love to do this mod to mine. Been contemplating a ss prop upgrade but this would be nice. Any info on part numbers etc. Cheers 🙂👍
Hi mate thank you! Best I can do is give you a link to the item I bought on ebay as I wouldn't want to recommend specific parts in case there was a difference with your engine. Hope this helps! I probably wouldn't go for a ss unless the engine was higher hp - www.ebay.co.uk/itm/204484940612?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=v8xGk1sDQhG&sssrc=4429486&ssuid=ftrrbQ4XSlW&var=&widget_ver=artemis&media=COPY
That honwave will fly! I'm so Impressed with my results. All the advice is in that video mate. Take your time and watch out for the clips on the ECU - they're quite delicate.
Do you need to replace the ecu or can you just do the carb and a prop? I see kits online that are just for the carb and prop and claim to be the conversion.
I just did this exact same thing with a new 15hp. Runs perfect, but at full throttle the red oil light comes on, just before, its fine but possibly its the electronic governor limiting revs? It's only a 10ft inflatable so it really gets up and moves. You have any issues at WOT?
No issues WOT for me. Check what your manual says for the light you're seeing. Static vs flashing, buzzer too? Sounds like it's probably rev limiting but check the explanation in the manual. Best to fit a tacho so you can measure your RPM and then increase prop size as required. Good luck!
@olirow I'm figuring it's the stock prop, with the higher hp it's getting the revs to high on the top end. I plan to reprop it as soon as I can to see if that sorts it out
Great upgrade. I am just wondering, how do you know that it gave you extra 5horses? And second question how much did you buy the ECU. Cause I see it’s listed for 900€ on eBay and this price tag is not worth the extra 5.
Hey thanks. I paid around £500 for the ECU. I know I got the extra 5 horses because the 9.9, 15 and 20 EFI engines are all identical aside from the ECU mapping and existence of the restrictor plate- identical otherwise. My acceleration and top speed went up and my rpms did too, moving back up to the 10" prop too. When I bought my engine the 20hp was hard to get hold of (covid), and there is no second hand market on the Isle of Man so for me buying the ecu separately was worth it. I've kept it too so I can sell the engine as the original 15hp and or sell the 20ecu separately in future
@Oakey22 the rpms with my 9" while 15hp were ideal. Once increasing the power, the 9" prop caused higher rpm, so switching to the larger 10" prop fixed that - more torque
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Nice Job looks Quite easy.Look forward to your test on the water. Great video as always.
Thanks Tony, straight forward enough but not cheap I'm afraid. Hopefully worth it as I can move back up to my 10" prop again now - less revs more cruise speed!
I’ve always wondered about this’ great video mate 😊
Thanks mate much appreciated. Turned out to be painless, and checking the key parts in the parts catalogue confirmed they're the same engine. Interestingly a mate with a Merc Mariner confirmed under the cowl is identical to my Tohatsu!
You've got the 9.8hp, haven't you?
Islander?
Yeah he has the 9.8, non EFI. The 9.9 is the EFI model.
Love my 2023 30hp Tohatsu 👌
Lovely engines
Shared on my tohatsu Facebook page
Thanks mate much appreciated
just bought a 2011 Mercury 15 and was reading the servie manual. The Manual is for 15 and 20 I was like oh I'm curious how much bigger the bore or stroke is on the 20.... looking at the specs everything was IDENTICAL b/w 15 and 20. I then figured this must be a manufactuer using an ECU to limit power like BMW and Porsche do which is easily flashable to get much more power. Then I remembered all the small Mercury outboards are just Tohatsu's.... found you on RUclips and then I see you holding a QUICKSILVER aka Mercury parts division box. I'm totally doing this to mine, what is the part number on the box?
Hey glad this was of some help to you. The performance improvement was well worth it in my opinion! Here's the link to the ebay listing I used, which includes Merc and Tohatsu part numbers! www.ebay.co.uk/itm/204484940612
I assume the block cylinder capacity etc is the same for the 20 and 15. You don't end up with a lightweight 20hp.
9.9, 15 and 20 EFIs are the same engines with different ECUs and presence of a restrictor plate. They share a parts catalogue aside from those. All weighing in at approx 44kg dry.
@@TheReelIsle Perfect! Thanks!
Hi, interesting video. I was wondering why didn't you get a 20hp in stead of the 15 as the weight is the same. Thanks Steve 👍
Hi Steve, thanks. I bought my 15hp during covid and it was one of the only engines available in the UK at the time - which would also ship to the Isle of Man.
A costly upgrade but sometimes you've just got to bite the bullet!
I know what you mean. I also had to wait a while to get my Tohatsu 20hp. Are you pleased with your tohatsu, I got mine in December 2022 and have done 40hrs so for. All tucked away for winter now. Enjoy your channel 👍
Thanks mate. Yes I absolutely love my Tohatsu - a solid piece of kit which gets used year round. The pre-winter service gets her ready for the cold weather
Hi and greetings from Germany. This is exactly what I was looking for. Great video and explanation. Unfortunately your links to the ecm do not work for me. Can you please tell me what part number the ecm has?
Hello! So happy you've found this useful. The part number listed on the eBay item I purchased is: Mercury: 8M0135817 & Tohatsu: 3RS-06401
@@TheReelIsle Thank you very much 👍🏼
Good day! Thank you for posting this video, I got a 2023 9.9 on dealer recommendation for a smaller boat(I’m not a big boater I’m new to it) and could use more power. I will be doing this soon. Can you provide a link for the ECU? My understanding is the 9.9 is the same as 15 and 20. What prop did you upgrade to? Thank you for the help!
Hello! So happy you've found this useful. The part number listed on the eBay item I purchased is: Mercury: 8M0135817 & Tohatsu: 3RS-06401. The original listing is no longer available I'm afraid so I can't share the link. Good luck!
Is it not possible to get the ECM remapped rather than buy a new one that looked very expensive. I wonder what would happen if you just removed the restrict or plate
I did research a remap and it is possible, but i was put off in case it bricked it. The only widely advertised option I could find was someone in Australia, oddly. I'm sure others can do it. This way, I have a 15 and a 20 ECU. When I sell the engine I csn include the buyers preference, and then sell the other still.
Removing only the restrictor plate would force the engine into a limp low rpm mode. I have seen videos of some boring the restrictor out a tiny bit, but not worth the risk in my opinion - it's important those injectors know how to correctly operate given the air flow
Just removing the restricter plate is all you need to do. It doesn't go into limp mode, it runs like a scalded dog! In my case with the motor on a 15,6 gheenoe classic weighing 245 lbs plus gear I had to go from the 10 pitch prop to 13 pitch to pull rpms down to 5900 rpms with a gain of 3 mph.
Hi guys, I did the restrictor removal only yesterday. Mine went into limp mode but I could defintely feel the extra power before it did. Guessing low oil pressure from possibly over revving. Turned it off and re-started and it was fine again. Having the extra power was way better.
I'm not sure what the effect is of removing the restrictor without replacing the ecu - I cant comment sorry!
Great video mate. I am currently running the 15hp Mercury 4 stroke. Would love to do this mod to mine. Been contemplating a ss prop upgrade but this would be nice. Any info on part numbers etc. Cheers 🙂👍
Hi mate thank you! Best I can do is give you a link to the item I bought on ebay as I wouldn't want to recommend specific parts in case there was a difference with your engine. Hope this helps! I probably wouldn't go for a ss unless the engine was higher hp - www.ebay.co.uk/itm/204484940612?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=v8xGk1sDQhG&sssrc=4429486&ssuid=ftrrbQ4XSlW&var=&widget_ver=artemis&media=COPY
Can't wait to see what difference it makes with my mercury 15hp efi to 20hp on my HONWAVE 3.8 ie3 🤪
Any advise please 👍🏻
That honwave will fly! I'm so Impressed with my results. All the advice is in that video mate. Take your time and watch out for the clips on the ECU - they're quite delicate.
@@TheReelIsle did you have to change the pitch of the prop?
I put the stock 10" prop back on again. While still a 15hp I ran a 9" but on a smaller boat.
Do you need to replace the ecu or can you just do the carb and a prop? I see kits online that are just for the carb and prop and claim to be the conversion.
This engine is electronic fuel injection not carb, so only need an ecu and removal of restrictor.
I just did this exact same thing with a new 15hp. Runs perfect, but at full throttle the red oil light comes on, just before, its fine but possibly its the electronic governor limiting revs? It's only a 10ft inflatable so it really gets up and moves. You have any issues at WOT?
No issues WOT for me. Check what your manual says for the light you're seeing. Static vs flashing, buzzer too? Sounds like it's probably rev limiting but check the explanation in the manual. Best to fit a tacho so you can measure your RPM and then increase prop size as required. Good luck!
Did you ever figure out why your light come on mate? Mine does the same ta
@olirow I'm figuring it's the stock prop, with the higher hp it's getting the revs to high on the top end. I plan to reprop it as soon as I can to see if that sorts it out
I see you bought the mercury 20hp ECU and not the Tuhatsu 20hp ECU. Any reason why? The mercury is about $100 more than the tuhatsu 3YL064010.
That was the only option available to me at he time
Can you just remove the restrictor? Shouldn’t the current Ecu be able to adjust fuel trim?
Needs a remap at least
Great upgrade. I am just wondering, how do you know that it gave you extra 5horses? And second question how much did you buy the ECU. Cause I see it’s listed for 900€ on eBay and this price tag is not worth the extra 5.
Hey thanks. I paid around £500 for the ECU. I know I got the extra 5 horses because the 9.9, 15 and 20 EFI engines are all identical aside from the ECU mapping and existence of the restrictor plate- identical otherwise. My acceleration and top speed went up and my rpms did too, moving back up to the 10" prop too. When I bought my engine the 20hp was hard to get hold of (covid), and there is no second hand market on the Isle of Man so for me buying the ecu separately was worth it. I've kept it too so I can sell the engine as the original 15hp and or sell the 20ecu separately in future
@@TheReelIsle that’s some great news. But is a reprogramming of ECU possible? Not buying a new one just reprogram the existing one?
@kostaskollias82 I believe so, there is an Australian website servicing that but I've not come across others. I suppose a dealer could.
@@TheReelIsle my dealer said don’t touch the engine 🤣
Spoken like a true dealer lol.
Straightforward which was great to see! Changing this part surely affects your warranty?
Changing this part would no doubt affect your warranty. The 15hp ecu would slot right back in though ;)
Interesting
Very good results- I'll post a vid soon
Don’t forget to upgrade your propeller
My 10" is perfect now, previously running a 9"
@TheReelIsle was this due to the upgrade to a 20hp?
@Oakey22 the rpms with my 9" while 15hp were ideal. Once increasing the power, the 9" prop caused higher rpm, so switching to the larger 10" prop fixed that - more torque