Fast boat

[@jakubkocian1145]

that is awesome!! I have a very similar engine could you show us a detailed explanation on how you made it more powerful, and rev much higher?

[@25hpboatracerman]

Hi Champion, Yes, absolutely 👍 there is a video on my channel detailing all the things I did to that motor. Cheers 🍻 Aussie Boat Guy 😎

[@cleitondossantos6955]

You are the best, you could take a course on preparing 2-stroke outboard engines. I would buy!

[@douger1517]

What a flyer great stuff. Need to see it on the fish nipper, short shaft motor on long shaft transom should run the same style as raised transom short shaft.😮

[@25hpboatracerman]

Hi Mate, yeah that would be interesting, not sure it would get the nipper on the plane though, worth a try 👌 cheers 🍻 Aussie Boat Guy 😎

[@michaelnelson912]

That’s nuts! Over 30 knots out of a 9.8! Bet you’re happy with it!

[@25hpboatracerman]

Hi Mate, I am pretty stoked 🤩 cheers 🍻 Aussie Boat Guy 😎

[@baenkt]

Just love your experiments! Rigging is sooo important. With the gas prices and the environmental aspect there is a lot that can be saved just by correct rigging. I´d love to see two tests. A way to see if you actually run the motor straight when you are going in a straight line, and if there are any gains with an offset motor. Moving it to your left would also make more room for you to sit more to the middle of the boat. Keep em coming!

[@25hpboatracerman]

Hi Mate, Love your suggestions 👌👌 didn’t even think of trying that but I like it. I built a cup on the trailing edge of the skeg to make the motor run true while in a straight line but I like the idea of offsetting and seeing what that does. cheers 🍻 Aussie Boat Guy 😎

[@baenkt]

@@25hpboatracerman Thanks! I´ve tried it on a bigger boat with a 115 Optimax, with good results. I´m curious how/if it would work on a smaller boat. We usually shaped the skeg by filing down the other side to get the same effect, but with less risk of introducing turbulence 😊

[@FYMM69]

@@25hpboatracermanI’m sitting here scratching my head wondering what the trailing edge of the skeg with cup in it would look like. Do you mean it’s flared out and if so, would that not create more drag ?? I absolutely love this stuff and very grateful to have found your channel

[@robertnewland90]

Awesome! Would love to see you mod a tohatsu 30hp!

[@25hpboatracerman]

Hi Mate, Yeah, me too 😂 love the Tohatsu 25 - 30hp I’ve had a few mates modify them but they already pretty well tuned. cheers 🍻 Aussie Boat Guy 😎

[@DaveGregory3298akaDJ]

That's frickin awesome work bro I love to have one of those gets you out to that fishing spot and back in a flash

[@25hpboatracerman]

Thanks Champion 👌 Yeah, it really moved now, definitely get you up a river fast. cheers 🍻 Aussie Boat Guy 😎

[@bradleyfarquhar2023]

That rips mate very fast good job.

[@25hpboatracerman]

Hi Mate, Cheers 🍻 yeah it’s screaming now. all the best Aussie Boat Guy 😎

[@andyboat7404]

Is there a play list on all the mods you have done to her ?? How is the low water pick up working out for you ? I am looking for a very light motor for a wee project tunnel boat i'm thinking of building. Boat is going to be around 8 foot long and weigh in just over 100kilo

[@25hpboatracerman]

Hi Mate, I don’t have a play list unfortunately. The low pickups are awesome, no issues at all and would not change a thing. My hull is 8.5ft and weighs 38kg dry (no motor, no tank, no safety gear, no driver). I still feel that is heavy. A 9.8hp short shaft two stroke Tohatsu is a light motor at 26kgs for sure. Not much torque though if your boat is going to weigh 100kgs dry? My setup would not get on the plane with another 15kgs with my surface props. A tunnel does get better bite at the prop though. Another good option is a 18hp Tohatsu (or 15 merc super - same motor) Keep me posted. Cheers 🍻 Aussie Boat Guy 😎

[@andyboat7404]

@@25hpboatracerman Wow! 38kg I plan is using 5mm nidaplas as a core then glass. I doubt i could get any where near 38kg. If a 18 Tohatso would be a better choice i am all ears :) I was used to big johnson V4s conrods balanced, pistons cut and weighed. Chris carson fiber reeds, high comp heads ect ect. Now i am not in the best of health so tiny motors and light boats are the order of the day. Love the stuff you do. I am surely not the only one who you have given inspiration to. Keep the videos coming all the tweaks give us ideas

[@qldshane]

Awesome, you’ve got over 20km/h out these modification’s! I’ve a healthy 9.8hp on a light 8ft punt, does 41km/h in still water.

[@25hpboatracerman]

Thanks Mate. Yeah I’m stoked, and 41kph is still moving. love the 9.8hp. Cheers 🍻 Aussie Boat Guy 😎

[@michalesinclair5274]

Thats bloody nuts mate😂

[@25hpboatracerman]

So true 😂 loving it, so much work though to get that power. cheers 🍻 Aussie Boat Guy 😎

[@dangerdan4x468]

Hey mate, absolutely love your videos, noticed you live close to me too! I have a 25hp yammi, with a on the fly jack plate, on a 3.7m v nose punt. Feel like the jackplate made barely any difference in top speed, tried 11¾ inch prop, 12, 13 and 14. The 12,13 and 14 barely got over 35kms and terrible holeshot, would struggle to get on plane. 11inch got 44kms and good holeshot. i feel like it might be the trim. the transom is angled back so the trim is quite far down, but adjusted all the way out on the trim setting. I feel like there is more top speed in it, especially now ive seen your videos. Any pointers would be greatly appreciated, thanks mate!!

[@25hpboatracerman]

Hi Mate, Yeah, love the coast 👍 I would expect a bit more top end speed than 44kph if it was me. Some questions I would ask - is the boat setup super heavy - driver, hull, motor, fuel, anchor, chain, anything else onboard? total moving weight? Is there a lot of weight up the front - casting deck - chains anchor? (that can kill top speeds) Is there a hook in the hull (where the rear section of the hull has an upward shape due to the transom twisting it up with the forces the motors place - especially if they have been overpowered in the past. out of interest is your 25hp the twin carb model? Cheers 🍻 Aussie Boat Guy 😎

[@dangerdan4x468]

@25hpboatracerman ill try to reduce some weight, the hull is pretty average, keeps cracking, might look at a smaller hull and repower with the same 25hp. I believe it is the twin carb. I was just so surprised with the different props, it didnt have enough power to get over 40kms. Thanks for the reply mate!

[@countryfriedent]

Flying mate

[@25hpboatracerman]

So much fun 🤩 cheers 🍻 Aussie Boat Guy 🍻

[@kungpho7325]

Love it mate.. 😊

[@25hpboatracerman]

Cheers champion 👍 all the best, Aussie Boat Guy 😎

[@choomah3937]

Hey mate I’m building my 8hp tohatsu, porting it, shaving the head, drilling the jets, and exhaust. What else would you recommend doing to it

[@25hpboatracerman]

Hi Mate, I would be very careful drilling jets, you will probably make it slower or run very bad. keep in mind the idle jet is around a 0.4mm hole, you make it 0.45 and she probably won’t idle well, same with the main. I would get my hands on a 9.8hp carburetor and use that. As you probably saw in my video on me modifying the same motor, I used an 18hp carburetor, putting a bigger throat carburetor on is when you really need to play with jetting and I ended up reducing my jets quite substantially. I would also play with the lower unit if your after top end speed. Cheers 🍻 Aussie Boat Guy 😎

[@choomah3937]

@@25hpboatracerman cheers mate I’ll see if I can get my hands on a 9.8 carby, I’m currently running a 9p which I have cupped on my quintrex 250 explorer and also added about 2cm of motor height. I’m expecting 40+ with the motor height and I’ve smoothed out the welds on the bottom of my transom to hopefully get less drag, before that I was getting 38kmh

[@nielsvosjes1874]

Nice, id like to see a 30 3 cilinder 😄

[@25hpboatracerman]

Hi Champion, Yeah, me too 😁 I just need more spare time. cheers 🍻 Aussie Boat Guy 😎

[@DktheWelder]

Wow crazy speeds mate , does it feel unstable?

[@25hpboatracerman]

Hi Mate, Yeah, she’s moving 😁 Feels a bit unstable but not too bad if your carful. should try it on one of your tiny tinnies 🤩 cheers 🍻 Aussie Boat Guy 😎

[@RUS18rus]

Salut! Nice, very nice. Do you planing any experiments & modifying for Yamaha 15 hp? I'd like to see the similar modifying Yamaha 15 and made the same accordance to your video.

[@25hpboatracerman]

Hi mate, thanks, I really appreciate your comments 👌 I’m sure you can do the same mods to a Yamaha 15hp but I’m not planning on modifying one unfortunately. cheers 🍻 Aussie Boat Guy 😎

[@Diesr]

Looks sweet what you horsepower do you think it produces by now?

[@25hpboatracerman]

Hi Mate, thanks 🙏 I reckon it’s about 14hp the speed comes from being tuned to rev higher. cheers 🍻 Aussie Boat Guy 😎

[@GordanSivec]

Dear Sir, Question if this can be done on any 2T horse 5 outboard or does it have to be Tohatsu…?

[@25hpboatracerman]

That video is of a modified 8hp. Yes you can modify any two stroke outboard, even the 2.5hp. you just need to make sure the gains are worth the effort. Cheers 🍻 Aussie Boat Guy 😎

[@Diesr]

Oh boy it’s a stupid question but I can’t find it on the internet and I’m afraid I’ll blow up my engine what’s the sparks per revolution for the tachometer on the 5hp mercury? Cause it’s idle at 1000 rpm I don’t think that’s right 😂

[@25hpboatracerman]

Hi mate, There are no silly questions. 1000rpm is about right for a small two stroke outboard idle. You cannot compare to a car. Cheers 🍻 Aussie Boat Guy 😎

[@Diesr]

@@25hpboatracermanany idea what the max rpm is before it throws a rod? Cause I’ve gotten my hands on a lighter gearbox from a Yamaha and currently working on it to see how it goes 😂

[@TheBrazzer2010]

Hey mate been watching your videos on KZbin for ages I learnt a lot! Quick question because I’m not sure you covered it in any of your videos, what’s the difference between a mercury 40hp lightning xr (m40d2 tohatsu) and a 50hp (m50d2 tohatsu) Or if you could make a video on it that would be great also From what I understand they are the same block and exhaust etc Cheers mate!

[@25hpboatracerman]

Hi Mate, thanks for your support 👍 Yeah I haven’t covered that. the Lightning XR is the 50hp block (the normal 40hp has smaller ports) to upgrade the 40 XR I believe you need the exhaust tuner, reeds, and carbs. anyone else who knows if there is anything else please chime in. Cheers 🍻 Aussie Boat Guy 😎

[@mightyboatmods]

I’d be keen to watch a modified tohatsu 25 build

[@25hpboatracerman]

Hi Mate, me too, don’t know if I’ve got the energy anymore 😂 Yeah, been there before with the 25hp. Raced the tohatsu 25 for years. One of my boats reached 102.3kph average speed over the kilo runs with a stock 25hp (lighter driver) believe it or not the modified ones are not heaps quicker, a bit but not compared to the work that goes into modding them. I moved up to 550cc supersport class and really got hurt, also rocked my confidence after a bad accident. all the best champion cheers 🍻 Aussie Boat Guy 😎

[@mightyboatmods]

@@25hpboatracerman I understand, appreciate the reply though. My 3.6m tinny with a 25 tohatsu clocked 63kmh 4th pin just me and my safety gear, not the lightest hull though, I’m keen on trying 5th trim pin but it is starting to chime walk, have the restrictor plate removed and some boyesen reeds, thinking of building one up this year though and putting it on a lighter hull 🤙

[@Diesr]

Het yeah got a quick question cause you are the 2 stroke wizzard My 5hp merc is running like crap and won’t get up to rpm since I put it on a shallower boat and when I put it on shallow water drive it works better should I drill out the exhaust nostrils for the exhaust backpressure or have you got any tips? Ps I’m realizing this boats low mount could be 90% of my problems right now cause of the waters backpressure 😂

[@Diesr]

it in fact was not the problem for the 30 hp :(

[@25hpboatracerman]

Hi Mate, Unfortunately it’s very hard to tell what the issue is without seeing the boat. I would not drill out the exhaust. how far below the keel is the cav plate? cheers 🍻 Aussie Boat Guy 😎

[@levijohnson1071]

Hi mate do you have a 50hp mercury 2 stroke crank 3 cylinder

[@25hpboatracerman]

Hi mate, unfortunately not. cheers 🍻 Aussie Boat Guy 😎

[@ardynottle]

Love it👍👍

[@25hpboatracerman]

Hi Champion, Cheers 🍻 Was a fun outing today. all the best, Aussie Boat Guy 😎

[@какяэтоделаю-ш7е]

Отличный мотор. У меня такой же , только 9.8. Правда в заводском исполнении.

[@a3_Beats]

Thats actualy the sickest thing ive ever seen!

[@25hpboatracerman]

Thanks mate, it’s a really fun little setup, gotta hood on 😂 cheers 🍻 Aussie Boat Guy 😎

[@25hpboatracerman]

Yeah, the 9.8hp Tohatsu is a good motor all the best Aussie Boat Guy 😎

[@aidencronje736]

Hey mate I upgraded from a 6 to a 25 sea pro 2 stroke Japan do you know how to make the throttle stiffer as mine is way to loose and I don’t have a book for the motor

[@25hpboatracerman]

Hi mate, Nice upgrade 👌 On some there is a friction device on the underside of the tiller handle. other than that, you will need to see if you can tighten something up under the cowl in the linkages or throttle system. Cheers 🍻 Aussie Boat Guy 😎

[@aidencronje736]

@@25hpboatracerman are you talking about the screw on the tiller handle?

[@25hpboatracerman]

Hi Mate, No, not the stainless screw, that holds the rubber handle on. You probably need to check if you can add some friction under the cowl to the linkages somewhere Cheers 🍻 Aussie Boat Guy

[@aidencronje736]

@@25hpboatracerman oh that’s what you meant I saw that video of you working on a 25 and you said the throttle is a bit loose for you I thought it’s a hidden knob somewhere

[@MrNotStock]

Hell yeah 😎 🔥

[@25hpboatracerman]

Loving it 😁 cheers 🍻 Aussie Boat Guy 😎

[@willknight1005]

Love your vids👍 Heavy tinny? 😂

[@25hpboatracerman]

Hi Mate, Thanks 🙏 Yeah it’s actually pretty heavy if you want speed plus hull design isn’t the best. I think the hull is near 40kgs now with the front grab bar. I really want to try that motor on a bath tub race boat, they weigh about 20kgs.

[@Vader...]

wow seriously only 8hp? That's incredible man, how did you do that?

[@25hpboatracerman]

Hi Mate, yep 👍 was an 8hp block, same as the 6hp and the 9.8hp but 9.8hp has the high comp head. I have modified the heck out of the block, there are videos on my channel about what I did if your interested. cheers 🍻 Aussie Boat Guy 😎

[@pm270100]

BACK IN THE DAY RED band merc new 50 hp on 12ft dehave tin boat !!!!!!!😯😯😯😯😯

[@25hpboatracerman]

Hi Mate, now that sounds like fun 🤩 cheers 🍻 Aussie Boat Guy 😎