Tohatsu Carburetor Swap 4HP to 6HP

[Alex F]

I‘m looking to upgrade my outboard to squeeze some more HP out of it. I remember discussions that some folks swapped the carbs from 6HP motor installing it on to 4HP motor with good results. Does anyone have source for the 6HP carb (the link I have is no longer working)?

Thanks,
Alex.

 

[RollerCoastr]

I was going to buy a spare carb for my 6HP, so I could do tear-downs and cleanings on my own schedule. That was this spring, and I eventually decided not to buy it, but I remember finding several sites offering them in the low-100's. I just did a quick search and found one at internet outboards for $139. I wouldn't pay much more than that...

 

[Alex F]

Maybe I'm using wrong key words to search on, but all I get is the repair kits. I found this OEM parts site, but I don't see the actual carb here either.

http://www.tohatsu-outboards.com/tohatsu-parts.htm

I found this one, but I don't think it's 6HP replacement carb:

[url]http://www.defender.com/product.jsp?path=-1|215570&id=1829514

[/URL]

 

[RollerCoastr]

yeah - that's the 2.5 horse. You wouldn't want to do that!

This is what I referred to earlier:

http://www.internetoutboards.com/partdetail.asp?id=354

 

[andy k]

http://www.internetoutboards.com/partdetail.asp?id=354RollerCoastr beat me to it

 

[Alex F]

Thanks guys. Looks like I'm on the right track now.

 

[MrFL54]

Thanks guys. Looks like I'm on the right track now.

Alex, did you find the right carb and have you put it on yet and ran it. I have a 4hp Mercury and was thinking of doing the same. The motor is actually a Tohatsu. Thanks

 

[390x]

I've done it. It was a night and day difference.

 

[Alex F]

Alex, did you find the right carb and have you put it on yet and ran it. I have a 4hp Mercury and was thinking of doing the same. The motor is actually a Tohatsu. Thanks

I still have plenty of time until new season. If I'm not going for new (larger RIB) then I'll be getting 6HP carb as a short term solution.

I've done it. It was a night and day difference.

Thanks for confirmation. I was thinking to add the tabs as well to have faster hole shot.

 

[390x]

I added the tabs too....both of them made a world of difference, but it won't plane out with two people. With just me, I can plane with the 6hp, but the boat just seems to small to plane with two people.

 

[PotatoAddict]

I've done it. It was a night and day difference.

Hi there. Was it simple to do? And did you also have to change the propeller? Thanks! I've got a 4 HP Mercury and I'm thinking about doing the same.

 

[390x]

yes, it's very easy. Two bolts if I remember correctly. I didn't swap the prop, but I think I'm going to just to see if there's a difference. I think there's only three props available anyway.

 

[Studman]

not to hyjack your post but does anyone know if you can add an internal tank to a 2007 6hp Tohatsu?

 

[Alex F]

not to hyjack your post but does anyone know if you can add an internal tank to a 2007 6hp Tohatsu?

I don't see why not if the body is the same. The question would be, is it worth the expense buying the tank with all necessary attachments.

 

[skolbe]

My Mercury 310 Sport will plane out with 1 person and a 6 HP - but will not with 2 people. I do not have tabs on mine. Debated on whether worth it. If I could plane with 2 people in it. I would do install the tabs.

 

[Blueone]

I've done it. It was a night and day difference.

I am really curious what speed increase everyone saw by changing to the 6hp carb only. Here is my setup in the pic a tohatsu 4hp on a Zodiac 8' cadet with the wood floor. I can only sort of get up on plane with one person leaning all the way forward.

Could you plane with 2 people weighing in combined maybe 325lbs with the 6hp carb ?

 

[Jimmy Buoy]

My Mercury 310 Sport will plane out with 1 person and a 6 HP - but will not with 2 people. I do not have tabs on mine. Debated on whether worth it. If I could plane with 2 people in it. I would do install the tabs.

Our 8'8" Achillies will plane at half throttle with two adults only using a 2stroke 5 hp Merc - but using those monster sized trim tabs! They really do work however, being on plane with that much weight at the relatively slow speed really throws a huge wake for a dinghy.

 

[Blueone]

A lot of times thats the only difference between 2 motors - a lot of guys on HP limited lakes will put carbs from a 15 on their 9.9 to get back to port quicker - if you look at motor specs a lot of the time the only difference between a 4 and 6 hp for example is the RPM at which they make peak power - the bigger carb is responsible for most of that increased rpm and therefore, power - dont think of it as hopping up the 4 but rather de-tuning the 6 - as some of these motors get more complex there may be a few more differences but the "carb trick" has always worked (unless you already have the highest rated engine from a particular block or series)

I got this out of the other thread... great info. I will change the carb regardless...you can't go wrong with more hp...even if it's only 2hp .... we are talking about a 50% increase... If anything it will just feel faster !!

 

[Blueone]

A very late update... 4 years! .. The other 6hp Thread reminded me of this one. I changed the carb this past summer ...The carb was under a $100 and that was all I did to convert it to 6hp... I didn't change the prop....and not sure you have to. That 50% increase in horsepower made a incredible difference in speed. I was never able to get up on plane with the 4hp. Here is the same video I posted on the other Thread.

https://youtu.be/nNPfhVMXioI

I left the 4hp badging on the outboard.... a sleeper has it's advantages...

 

[RidgeRunner]

I have a Yamaha 4hp that's going in the shop for some minor warranty work, the parts guy verified the carb difference (main and slow jet) and put them on order for me. 6 hp, here I come......