Low water pickup outboard

In this video I build a lower unit to the Borneo specs (they run most of there gearcase like this when racing)
Hope you enjoy,
Cheers 🍻

[@DktheWelder]

Wow outboard wizard! So cool not many videos showing this type of stuff great work

[@25hpboatracerman]

Hi Mate, Thanks, that’s a first, Outboard Wizard 👍 sounds like a better name than Aussie Boat Guy 😂 I like it. Really appreciate your support champion. Ps: your videos are amazing and what you do is inspiring. Everyone should check out DK the welder on KZbin he’s awesome 👏 cheers 🍻 Aussie Boat Guy 😎

[@MarkValascun]

Also if you look up The Fabrication Series he does a great job explaining how to weld castings better.

[@MarkValascun]

Bro I searched FAR and WIDE across you channel to find this video when you posted the other vid!😂

[@25hpboatracerman]

Hi Champion, That’s funny 😆 glad I put it up quick then. cheers 🍻 Aussie Boat Guy 😎

[@208miuwu]

Looks like a mini version of a (CLE) Crescent Leading Edge gear case we use here in the States. Nice set up

[@25hpboatracerman]

Cheers mate 👍 I have modified it a bit further with a smaller skeg and a better nose cone. Super fun making and testing that whole motor. All the best, Aussie Boat Guy 😎

[@teeanahera8949]

With the oil drain screw being recessed so far will that not create more drag through mini vortices forming than if the screw was flush with the external casing. I would experiment with another washer under it to bring it out a mm and solve your intrusion problem too.

[@25hpboatracerman]

Hi Mate, thanks for your comments and very well picked up 👌 I know it looks recessed in the video but it is actually nearly flush. I have seen that the omc race lower units that are a split case have a fair few recessed bolts in the lower unit that don’t seem to affect the performance. I do know that a protruding bolt or screw head does affect the performance for sure. if I was to bring my fill screw out a mm it would be slightly proud. When I was testing in the video I was using an old washer gasket and the new one is slightly thicker. thanks champ cheers 🍻 Aussie Boat Guy 😎

[@劳永康]

Wow, your video is great, I learned a lot of useful things from it☺☺😎

[@25hpboatracerman]

Hi Champion, Glad you enjoyed it! All the best. Aussie Boat Guy 😎

[@ThePopypete]

😉😁 enjoying your CAN do attitude . You remind me of the bloke from the worlds fastest Indian 😂😉🤔🤗

[@25hpboatracerman]

Hi Mate, Really appreciate your comments, I do try to do most things, don’t always succeed but always trying to learn. cheers 🍻 Aussie Boat Guy 😎

[@DanielJames-pn2dt]

Love this job- so nicely done. I have tried to work out how the water gets to the pump from the front of the nose cone in the factory low water pick-up racing gear cases from mercury and can't see how they do it? With the after-market kits, like the bob's etc, they have an external hose running back from the nose cone but that's obviously not there on the factory ones. Can you explain? And what's the disadvantage, ie why aren't there more factory versions available?

[@25hpboatracerman]

Hi Mate, Yeah, the factory low pickup lower units just have different water tube setups inside the lower unit. They often have a vertical water shaft in front of the drive shaft instead of behind. The reason we don’t see more low water pickups from the factories is because they are not needed for the majority of boaters and a standard lower unit without the cone performs exactly the same when low in the water as a nose cone case. the standard case also doesn’t have the pointy cone poking out the front which is better for the standard boater too. Probably cheaper too without the low pickups. In saying all that, a lot of manufacturers are adding extra water pickups at the front of the lower unit bullet which I am loving. Cheers 🍻 Aussie Boat Guy 😎

[@DanielJames-pn2dt]

Thanks@@25hpboatracerman , How do they get the front vertical water shafts in the lower units to mate up with the back shafts in the mid section? Are there channels wrapping around the drive shaft to get back there? And do you thing the noise from the high exhaust outlet is compatible with pleasant boating?

[@martinlindberg1983]

OMG!!! You are a true professional! I really love this stuff. I had a couple of out boards with nose cone, low pick up and hydraulic lift but nothing as beautiful hand made like this. I am stunned about your skills. Please keep up the good work. You know, people love to watch this technical/mechanical awesomeness for hours :)

[@25hpboatracerman]

Wow, thanks, that’s one of the nicest comments I’ve received and I really appreciate it. I have so much fun tinkering with that kind of stuff. All the best and cheers 🍻 Aussie Boat Guy 😎

[@DatBlueHusky]

thats so sick, i bet it will keep the lower end lasting longer without all the heat

[@25hpboatracerman]

Thanks Champion 👍 Yeah, it’s working surprisingly well. cheers 🍻 Aussie Boat Guy 😎

[@nerd1000ify]

very nice work. I especially liked your improvised home made counterbore tool for the drain plug, i'd have horribly over-engineered something like that and wound up spending a week on just the tool.

[@25hpboatracerman]

Thanks Mate 👍 Don’t worry I too tend to over do things sometimes 😂 your not alone in that. cheers 🍻 Aussie Boat Guy 😎

[@jackmarsh7328]

So that the only modification you need? After that just assemble as usual?

[@25hpboatracerman]

Hi Mate, You can just add the low pickups like in the video and assemble the lower unit as usual. Obviously if you modify the whole motor (porting, high comp head, big carb) it will perform even better. You can check out the other mods I did to that motor on the channel if you’d interested. Cheers 🍻 Aussie Boat Guy 😎

[@jackmarsh7328]

@@25hpboatracerman thanks mate. Btw i have 60hp yamaha. Searching for big carb that can just PNP with it and bit of porting.

[@eliasedits4848]

Do you reckon you can do that in a 25 merc 2 stroke?

[@25hpboatracerman]

Hi Champ, the guys in Borneo do it to all their race motors. cheers 🍻 Aussie Boat Guy 😎

[@cleitondossantos6955]

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

[@dangerdan4x468]

Love what you are doing mate with all your videos, keep it up!!!!

[@25hpboatracerman]

Hi Champion, I really appreciate your comments, I am have fun too 😁 cheers 🍻 Aussie Boat Guy 😎

[@muzharcus3195]

Thing is a work of art 😮

[@25hpboatracerman]

Hi Mate, Yeah, I’m really happy with it 👌 I still need to find some time to do more testing, I’m hoping for more speed of course 😂 cheers 🍻 Aussie Boat Guy 😎

[@miketee2444]

Nice looking chopper you've got on there too. In America the SSM cases for little Mercs are very hard or expensive to find. This isn't a bad option considering buying one costs a couple grand.

[@25hpboatracerman]

Hi Mate, Thanks for your comments 👌 Yeah, those little SSM cases are awesome, love the little 15hp omc race lower unit too. Not sure mine would keep up, maybe 🤷‍♂️ would be good to make one for a 15hp and see the results. Cheers 🍻 Aussie Boat Guy 😎

[@Rlip]

You could just crush a copper tube and run it low, or built a channel into the skeg. Lot of work fora a 5hp mate but years ago we had a 5 hp race I used an old mercury 5hp green top 4 cylinder with a brass race prop . Got 2nd place as I was a kid and light , it kind of bogged for a couple seconds in the beginning of the race for I would have been 1st place 😂

[@25hpboatracerman]

Hi mate, Yep lots of work for a little motor but it’s a hobby, I find it so much fun to squeeze these little motors. didn’t know that Mercury made a 4 cylinder 5hp? I know they made a 4 cylinder that was a 25hp when they where white. sounds like you had fun 🤩 cheers 🍻 Aussie Boat Guy 😎

[@jevers123]

Awesome that's crazy good, I just did a low water mod for a race boat , love you'r maths

[@25hpboatracerman]

Hi Champion, Thanks for your comments 👌 I had a lot of fun modifying that lower unit, I still want to spend more time on setup to squeeze more speed of course 😂 cheers 🍻 Aussie Boat Guy 😎

[@thelikebutton4405]

You're the man! Thanks for sharing this idea, with bobs nose cone kits going up in price, seems worth it to me to make a case like this being im an aluminium fabricator myself, and all the spare junk i have laying around lol. Going to be giving it a go with the old mercury tower of power 150.

[@25hpboatracerman]

That’s the go 👍 cheers 🍻 Aussie Boat Guy 😎

[@charlesoverton]

You are close to being a toolmaker. I will have to keep an eye on you.

[@25hpboatracerman]

Cheers mate, I’m always tinkering and trying to learn new skills. all the best 👍 Aussie Boat Guy 😎

[@Rob-fx2dw]

You could fill that drain plug hole with a weak polyester filling combined with micro spheres which makes the expoxy weak enough to sand smooth and then dig it out when you want to later remove the drain plug for an oil change.

[@25hpboatracerman]

Hi mate, Yeah agree, had a few mates do that on their race boats, it works well. might go down that track for sure. cheers 🍻 Aussie Boat Guy 😎

[@donsscooters]

I love it! Thanks for sharing the project. Keep the videos coming.

[@25hpboatracerman]

Hi Champions Thanks, will do! cheers 🍻 Aussie Boat Guy 😎

[@oztrekgelsoft8409]

Fantastic video best mod for low water pick up i have seen 👌

[@25hpboatracerman]

Hi Mate, thanks so much for your encouragement, it was a fun project and works really well. The guys who race boats in Borneo do it like that. cheers 🍻 Aussie Boat Guy 😎

[@teeanahera8949]

Way too awesome for words! (Except for those 5.)

[@25hpboatracerman]

Hi Mate, That’s so good 😊 thanks so much for your encouragement. all the best 👍 Aussie Boat Guy 😎

[@Bill-wz6tw]

Awesome project thanks for sharing it

[@25hpboatracerman]

Hi Mate, Thanks so much for your encouragement 👍 I had a lot of fun making it. cheers 🍻 Aussie Boat Guy 😎

[@NinoSpinner]

really excellent, congratulations, a nice job

[@25hpboatracerman]

Thanks so much Mate 👍 I really appreciate you taking the time to comment, I’m really having fun with this motor. cheers 🍻 Aussie Boat Guy 😎

[@ardynottle]

Loving the mods and the vids

[@25hpboatracerman]

Thanks Mate, I’m really enjoying putting the vids up too 👌👌 having so much fun 🤩 cheers 🍻 Aussie Boat Guy 😎

[@acurarl9929]

Why only holes On one side vrs both sides???

[@25hpboatracerman]

Hi Mate, Normally just on the right side as that side is being pulled to the right by the propeller so more water pressure on that side. cheers 🍻 Aussie Boat Guy 😎

[@dr.batts9025]

What is your experience with Perma Gap spark plugs? what are their pros and cons? I'm looking to replace my plugs and considering upgrading them.

[@25hpboatracerman]

Hi mate, I always run the stock spark plugs or if I’m doing performance stuff sometimes the same plug without the resistor. Unfortunately I have not used Perma Gap plugs so don’t really have much input for you. cheers 🍻 Aussie Boat Guy 😎

[@GoldenCroc]

Hello. I am curious, can you tell me what, in your estimation, are some of the advantages and other considerations of doing this compared to just using a separate water intake pickup (hull mounted) and from there a flexible hose to a drilled hole in the gearcase where it can enter? Great video, thanks!

[@25hpboatracerman]

Hi mate, Well, for starters it is heaps more work 😂 than an intake on the hull and a tube. Advantages are it looks really cool 😁 also it is self contained so don’t need to add pickups on hull etc and can be swapped to other hulls without any need to drill more pickup holes in other transoms. Also if the water feed line from the hull to the leg splits or falls off the motor cooks. I have done gear-cases both ways and both work well to run the motor high. I am also happy either way. cheers 🍻 Aussie Boat Guy 😎

[@bebeslife4519]

I’ve heard that some outboards are not self priming. That being said, I’m curious how does the impeller pick up the water if the water level is way before it. Does the impeller create an air vacuum?

[@25hpboatracerman]

Hi Mate, Very good question and I was worried about the same thing as I was making that lower unit. Knowing the racers in Borneo run their lower units like that I was happy it was proven to work. From my tests the rubber impeller does create a vacuum which is enough to draw the initial water up, once it’s full of water no probs. As you can see in the end of the video, it does draw water very easily when started which I was pleased. all the best, cheers 🍻 Aussie Boat Guy 😎

[@AquaMarine1000]

Most two-stroke exhausts are turned to produce power at certain revs, usually at the top end. How will the modified exhaust change the back pressure and thus high-end performance? Cheers

[@25hpboatracerman]

Hi mate, you are correct 👌 I have already made a custom exhaust tuner in the leg and actually wanted the outlet to be bigger for more flow at high rpm. it’s working a treat, just got back from more testing just now 😁 cheers 🍻 Aussie Boat Guy 😎

[@AquaMarine1000]

@25hpboatracerman The constraints to design an internal outboard exhaust system are not easy. That cone shaped expansion chamber on two-stroke race bike exhausts is designed to produce a shock wave to force back the intake fuel air mixture from existing the exhaust port. This is what makes two-strokes peaky with such a tight power-band. I knew a guy who powered a gyrocopter with an Evinrude outboard power head. He was a smart guy but could never get the engine to run right. The timing of the back pressure is critical to revs. This consists of getting the exhausted pipe length and expansion chamber cone angle and length as accurate as possible to the millimetre. Thanks for the chat. Cheers

[@25hpboatracerman]

Hi Champion. yep, you are spot on mate. Not easy in the trunk of an outboard to get the exhaust correct. But in saying that, you are talking about tuned pipes which outboards don’t go to that level of tuning unless in some outboard racing classes where they run external pipes. I have done a few test days now with the outboard and I’m very happy with the power (way more than stock) as I have modified the whole powerhead. I did put up a video on the mods a few vids back. Proper tuned pipes - like those on a two stroke dirt bike would definitely increase an outboards power with the returning sound waves forcing pressure back into the chambers but no room internally in the leg unfortunately. These motors will run (with more power than factory) even with a trumpet exhaust straight off the exhaust ports. Cheers 🍻 Aussie Boat Guy 😎

[@AquaMarine1000]

@25hpboatracerman I agree. I'm looking forward to the next video. Cheers

[@needmoreboost6369]

@@25hpboatracermanon the topic of tuned pipes I’d had experience fitting an expansion chamber to one racing motor, a 3.5 cc thunder tiger nitro outboard for an rc tunnel lol, but in all seriousness I’d say getting the total benefit from adding chambers would need ports to suit! Id think because these are ported for torque and quite low rpm’s! Id say the overlap and timing may not be well suited to pulse scavenging as well as a higher rpm port set? Id never measured port timing on outboards but it’d be interesting to mess with! Especially with a loose boat and big cleaver prop! The combined exhaust for multiple cylinders usually isn’t very effective compared with individual chambers or at these revs trumpets, the expansion chambers would have to be huge at 7k rpm but probably roughly half that size for 14k rpm

[@oneida80100]

Excellent work! Thanks for sharing.

[@25hpboatracerman]

Hi Mate, Thanks so much for your comments, I really enjoy sharing this stuff too. cheers 🍻 Aussie Boat Guy 😎

[@charlesoverton]

That looks like a machine weld. Can you weld that good? Certified you can get a good job.

[@25hpboatracerman]

Hi Mate, Thanks for your encouragement 👌 I still have a long way to go with my welds. cheers 🍻 Aussie Boat Guy 😎

[@benashby6162]

Thank you publishing this video. Great content and great resource.

[@25hpboatracerman]

Hi Mate, Thanks so much for your comments, I really appreciate it 👌 All the best, Aussie Boat Guy 😎

[@Foilonly]

Hi buddy, any way to get in touch with you. I have a pretty interesting project and would like to chat with you.

[@25hpboatracerman]

Hi mate, I am in the process of opening up a messenger so people can contact me. cheers 🍻 Aussie Boat Guy 😎

[@ABminusGEDREHT]

Cant Wait! @@25hpboatracerman

[@stevescott8764]

Nice work glenno, can’t wait for the 30d gear case

[@25hpboatracerman]

Hi Steve 👋 Cheers 🍻 Me too 😁, wish I had more time 😂 to get the 30d stuff organized. By the way, you are a big part mate of why I’m so into this stuff, cheers for all the help through the years. All the best mate Glenno

[@FlyingZombiekiller]

Thank you for sharing your knowledge with us!

[@25hpboatracerman]

Hi mate, I am happy to share my passion with anyone who is interested 😂 thanks for your encouragement champ. cheers 🍻 Aussie Boat Guy 😎

[@Phantom-mk4kp]

Be honest. The reason your not grinding down the seam welds is because they look so pretty 😊

[@25hpboatracerman]

😂😂😂 that’s funny. Maybe that’s the real reason. All the best champion. Cheers 🍻 Aussie Boat Guy 😎

[@michaelsimpson9779]

Nice work as always.....👍

[@25hpboatracerman]

Thanks Mate 👌 Really appreciate your comments. Cheers 🍻 Aussie Boat Guy 😎

[@shannonzygmont9019]

Hi is there any easy way to up the hp on a 2006 mariner 8hp i have watched the comparisons on the 8 Vs 9.8

[@25hpboatracerman]

Hi mate, Unfortunately not worth it for the extra 1.8hp to buy and put on all the 9.8hp gear. you would need to replace the carburetor, the head. the cam on the stator and the stator stop. Even after changing out those parts I find it hard to notice a big difference between the 8hp and 9.8hp. cheers 🍻 Aussie Boat Guy 😎

[@shannonzygmont9019]

@@25hpboatracerman cheers for the reply love your videos and very insightful good to see the small motors getting some attention

[@quelincutajar8241]

Nice worke and thanks for sharing

[@25hpboatracerman]

Hi Mate, My pleasure and thanks for your encouragement 👌 cheers 🍻 Aussie Boat Guy 😎

[@brendanbarker2095]

very clever

[@25hpboatracerman]

Hi Mate, Thanks 😊 I’m having so much fun tinkering with this stuff. cheers 🍻 Aussie Boat Guy 😎

[@riverdragonmarineservice441]

Nice :) Mini XS case.

[@25hpboatracerman]

It sure is! 😂😂 cheers 🍻 Aussie Boat Guy 😎

[@bradleyfarquhar2023]

Good job mate.

[@25hpboatracerman]

Hi mate, Thanks champion 👍 cheers 🍻 Aussie Boat Guy 😎