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Small Outboards / Power to Weight 2 vs 4

RiverDave

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I have started this thread before on another board, and I think once years ago on here.. but the search came up pretty dry for me.

That being said, I have a 10' Schiada and a 12' Schiada. These boats are heavy for their size, and I'm looking for some good power to weight ratio small engines. Reliability is key (so some clapped out race motor that isn't gonna start everytime isn't an option) Electric start, etc..

My old one had a tohatsu 40 on it.. I felt it was a little underpowered. I would like it to be a little "over powered" to be blunt, and I can put a restrictor on the throttle if a kid ever drives it.

So that being said.. Suggestions?

I know they race the tohatsu 40 in a stock class, I think it's called "FAT C" and then some unlimited class?

Would a fat C motor be appropriate?

Or should I go with a newer technology 4 stroke? E Tec?

Suggestions.. and any "Power to weight ratio" charts that compare outboards would be great.

RD
 

TomD

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For the 12' a Johnson Stinger 75 horse would be pretty kick ass if set up right.
 

Yellowboat

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now days there is not alot of diffrence in wieght between a 2 and a 4


where you will see the real diffrence is in accleration.


For the most part a 2 will get you there faster and have a slightly better top end.
 

Tom Brown

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For the 12' a Johnson Stinger 75 horse would be pretty kick ass if set up right.
I couldn't agree more with TomD. That would be a bad ass engine on the 12. Light. More power than you could use. One of the more reliable engines ever made. Probably a nice margin past the safe level on a 12' Schiada.

I ran a 70hp OMC on a 14' Aluminum Starcraft. It was nicely powered. The engine was not too heavy at all for the little Starcraft. The 75 is a nice little bit more power and it has the "performance prestige" factor in outboard circles, like a 2.5 EFI Merc or 300X.

Ultimate engine for the 12, if you ask me.
 
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RiverDave

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Got any pictures or stats on the 75 stinger? HOw much does it weigh?

RD
 

Tom Brown

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Here's a great shot of a Stinger on a Rapid Craft Cyclone. I'll bet he owns his division. The guys running the Merc 80hp 4 cylinder mills had little chance against the 65 Stinger.

http://rides.webshots.com/photo/2589393450091848696PPjqIk


Check out the chine walk on this little 10er with a 75hp Stinger. lol!

The camera boat is running at 36 mph in this vid.

YouTube- Pioner 325 w. 75hp Johnson Stinger high-speed pass


I think the OMC 3 cylinder engines weigh around 170 lbs? Can anyone cite the actual specification?
 
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Flying_Lavey

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Mondorally

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http://www.johnson.com/NR/rdonlyres/D2602C92-505F-4618-BF33-542CB4530CBB/0/2007_EvinrudeBrochure.pdf

According to that, the 75hp Evinrude (anything over 25 hp is Evinrude now) 3cyl is 320 lbs. At that point, it looks like you might as well throw a 90hp on it since its the same engine pretty much and same weight.
The 90hp is the best power/weight ratio:D... but the 60hp is probably a bit more realistic.



90hp @ 320lbs = 3.6lb / HP
70hp @ 320lbs = 4.3lb/HP
60hp @ 240lbs = 4.0lb/HP
50hp @ 240lbs = 4.8lb/HP
 
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TomD

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Cut the heads a little, clean up the ports, fatten up the jets a touch & the "Stinger" will sting ya.

What's the bottom of the boat like ?
 

Tom Brown

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Cut the heads a little, clean up the ports, fatten up the jets a touch & the "Stinger" will sting ya.
So... you're suggesting that, not only he put a huge engine on a tiny boat, but that he also hop it up a bit? :D

Don't just put the 572ci/lenco in the Smart four two, make sure it's got quad turbo chargers and don't forget the carbon fiber intake manifold and valve covers... it's all about power to weight. :D
 

RiverDave

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Cut the heads a little, clean up the ports, fatten up the jets a touch & the "Stinger" will sting ya.

What's the bottom of the boat like ?
It's just a v-bottom.. 10' and 12' Schiada. You can see pics of the boats in the schiada projects section.

RD
 

RiverDave

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In looking at the evinrude website they have a "competitive comparison"

I'm looking aruond at the 40 - 60 HP Etec..

I noticed though on the 50HP they have a weight of 240lbs.. A yamaha 4 stroke is 247. The yamaha 2 STROKE is 189lb..

The old outboards might be a better solution. I'm kinda worried about reliabillity, parts, etc.. That and the fact that they look like overgrown toasters.

RD
 

skifaster

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I can't imagine a 250lb engine working on the back of a 10' or 12' schiada. They are so weight sensitive. 75 hp would be awesome, just don't see how it could handle the weight.
 

Tom Brown

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The old outboards might be a better solution. I'm kinda worried about reliabillity, parts, etc.. That and the fact that they look like overgrown toasters.
If it were me, I'd rather have an older OMC 3 cylinder. Frankly, I'd take any 3 cylinder mill.

If I could find a Stinger/Hustler of any year, that would definitely be my first choice. They are much sought after though, so they come at a premium price if you can find one at all. After that, I'd look for a mid 80s, 70hp, 3 cylinder. Even a 60hp, 3 cylinder would be fine, though.

I'd trust an old 3 cylinder's reliability before I'd trust any new engine. They're just so simple. They don't even have VRO, so I guess that's a problem if you don't want to pre-mix.

I hessitate to say I'd take a vintage OMC over a new Yamaha but the old OMCs were so simple... crank, pistons, reeds... nothing else moved.
 

Crazyhippy

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I hessitate to say I'd take a vintage OMC over a new Yamaha but the old OMCs were so simple... crank, pistons, reeds... nothing else moved.
Including the Glastron they were attached too...:champagne::rotflmao:
 

skifaster

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did you ever see how much stuff I had on the transom of my old 10'er?

http://www.riverdavesplace.com/forums/galleries/Bubbles/Photo Shoot/index.html

RD
Ya, I guess with the gas tank in the front helps counteract some of the weight. Mine has the tank in the rear still as well as the battery. So it is pretty tail heavy. How big was your tank in Bubbles and how is it mounted to the floor under the bow? What kind of fuel tanks and where are you putting them in the new 10'er and 12'er?
 

RiverDave

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As far as the 10 & 12, I haven't really decided yet how I'm going to rig them.. I might do saddle tanks in the 12. The 10 will probably get another front mount tank if I had to guess.

The tank was massive.. I don't remember how many gallons it held, but I want to say 12+ gallons? (I dunno) We modelled it in cad and just pushed it out as far as we could to the edges of the floor. The tank just sat on these 1/4 inch rubber pads that I made. I had a bulkhead installed in the front of the boat, and the tank was through bolted to the bulkhead.

Here's pics of the tank (Schiada96 made the tank for me), pre-powdercoat, and you can see the straps that through bolt it to the bulkhead. The holes on either side of the tank in the last picture were for speakers, but that is how we accessed the back of the bulkhead to through bolt it.

Tank after powdercoating (Note the flanges on the sides)





Pre powdercoat with through bolt straps on top.





RD
 

Tom Brown

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What kind of physicist takes a tiny boat and weighs it down with tons of heavy shit?

Dave... tiny boat... keep it light... keep it simple... that's what it's all about.
 

RiverDave

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What kind of physicist takes a tiny boat and weighs it down with tons of heavy shit?

Dave... tiny boat... keep it light... keep it simple... that's what it's all about.
Brown I'm not racing these things.. I want something I can fill up, and drive the shit out of it for 4 - 6 weekends.. then fill it up again.

what kind of idiot builds a trailer that you can't tow on a freeway? Answer RiverDave.. :D

RD
 

Tom Brown

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lol!

Oddly, I think I get it. You want a hot rod, not a race car. :cool:

I really enjoyed your last project so I'm looking forward to these two. :)

Keep in mind, I never said it wasn't cool... just maybe not the best idea, from a performance stand point. If you have a 600# boat (fully rigged) and add 200# of shit... it's going to bog that boat down like a carton of frp Chesterfield cigarettes.
 

TomD

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Brown I'm not racing these things.. I want something I can fill up, and drive the shit out of it for 4 - 6 weekends.. then fill it up again.

what kind of idiot builds a trailer that you can't tow on a freeway? Answer RiverDave.. :D

RD
I'd still put a 70HP OMC on it.:D:thumbsup
 

Flying_Lavey

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The only problem That I can maybe see with getting the older OMC is the parts issue. Since Im a merc guy I dont really pay attention to OMC dealer locations but I dont really recall seeing any in or around Parker. Please, correct me if I am wrong though. At least with the Merc there are a few places that have Merc parts and stock them in Parker. And the Yamaha, you have the dealer right there in town.
 

TomD

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I'm a MERC guy also but I'm pretty sure you can get factory parts for them still. One thing is for sure parts are WAY cheaper than MERC.
 

wildone

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Funny you mention it.... this pics was posted today ;)

Thats the vesely's 10. i believe it has a 40 horse on it with a lifting foil. it runs really nice. super reliable. not sure of speed only been in it once with two of us and jerry didnt really push it i think mid 30s is all we ran but it had some left
 

RiverDave

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Thats the vesely's 10. i believe it has a 40 horse on it with a lifting foil. it runs really nice. super reliable. not sure of speed only been in it once with two of us and jerry didnt really push it i think mid 30s is all we ran but it had some left
It has a 25HP on it, if I remember right..

I'm shooting for more like low to mid 50's (mph) BTW..

RD
 

rivermobster

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just a suggestion, you might wanna call Al Stoker at John's Custom Marine. He's kinna wacked, but he DOES know his shit about outboards!! He's built some scary fast stuff for sure.
 

wildone

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It has a 25HP on it, if I remember right..

I'm shooting for more like low to mid 50's (mph) BTW..

RD
cool. i know hes changed out the motor a few times.

any idea how much one of the merc formula 60s would go for? be a bad ass motor for the 12 maybe to big for the 10?

whats the progress on those two boats anyways?
 

STV_Keith

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I'm with Tom and the others...older Stinger 75 / Strangler 75. They were 15" midsections too, so short shaft for lower weight placement. ST60 might be an option too. Check this thread...SST60 and a guy says he has two 75's: http://www.boatracingfacts.com/forums/showthread.php?t=10595

Too bad you don't want a race motor though...this is BAD ASS for the size:

 

RiverDave

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Keith why would a 60 that's all taken apart cost 5300 bucks? And the two 75's are only 1500 & 2K?

RD
 

STV_Keith

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The 75's are older motors - all old OMC crossflows. The 60 is not taken apart - it's just the powerhead part he's selling. Looks to be a modded one too.

Look at the last two posts in the thread...guys saying they know where to get more Stinger stuff cheap...
 

RiverDave

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Thanks Keith, I'm a little ways out on buying a motor right now... (hemoraging money into like 5 projects including the new site)

But I'm trying to narrow down which ones will be a good choice for the 2 mini's.. I should be ready to buy in about 1 month.

RD
 

TPC

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New 75 hp motor weights:

Honda 75 HP 4 stroke 355 lbs. Oftentimes Honda rates their stuff wet.

Zuki 75hp 4 stroke 345 lbs

Evinrude 2 stroke 75 HP 325 lbs

About a 20 lbs saving with the 2 stroke. Not much really.

When I was big into Minis I wouldn't have anything less than 60 HP.
Also,, many of the smaller HPs have goofy shaft length sizes that may or may not line up properly with the bottom of the boat for correct performance.

So ya gotta really do your homework about if it'll line up OK.

Yamaha changed their shafts lengths one year and just blindsided and screwed everyone that bought them before we realized they varied away from industry standards.
What an expensive fuckstory that fiasco was for those that couldn't use adjustable mounts, which is almost everyone.

The most important thing on the Mini Schiada is the center of the prop shaft lining up exactly with the bottom of the boat.
I mean right on the money and read that CENTER up and down and port to starboard..
Getting it correct is a HUGE BFD.

Their are reverse rotation motors out there for sale. So eyes wide open on that Pandoras box of headaches too.
Don't go near them no matter what kinda plan of single mount application you have for your mini that is.
Your problems will have just begun, and you'll never solve them.

Oh brother do I have stories about guys that backed deep into hell trying to make single mount reverse rotation motors work on minis.
 
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STV_Keith

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New 75 hp motor weights:

Honda 75 HP 4 stroke 355 lbs. Oftentimes Honda rates their stuff wet.

Zuki 75hp 4 stroke 345 lbs

Evinrude 2 stroke 75 HP 325 lbs

About a 20 lbs saving with the 2 stroke. Not much really.
Don't know RD's budget, but I'm betting the older 2 strokes are a bit lighter than that. Hell, my 2.5l 260hp "hi-perf" V6 is only 375#. I think the old Stinger 75's were a lot less than that.
 

TPC

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Wow.
Why are the newer motors so much heavier???
 
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