30 HP Yamaha with 50 hp Tohatsu 50 Carbs

[grayson]

Hi guys,
i'm about to fit 50 Tohatsu carbs to my 30 hp Yamaha 3 cyl 2 stroke, does anybody here please have any pictures or pointers on how they set up the linkages?
It looks pretty different to the old yamaha set up on there

[Roflhat]

Got any photos? On my Tohatsu 50 with yamaha 70 carbs the tohatsu carb throttle linkage worked as the carbs are closer together

[grayson]

Got any photos? On my Tohatsu 50 with yamaha 70 carbs the tohatsu carb throttle linkage worked as the carbs are closer together

Not yet, still waiting on mine in the post. My friend is in the middle of his and we have come up with two problems, the linkage and the vacuum port for the fuel pump not lining up.

For his linkage it's not too complicated as he runs a foot throttle on a little wing boat, for me I run a tiller, the linkage looks like it will be a bit of work
Here are our boats

[DuckLn]

Grayson where are you located?

[Roflhat]

Overpowered tinnies, got to be in Aus? Love that second photo too

[grayson]

Grayson where are you located?

In Australia,

[grayson]

Overpowered tinnies, got to be in Aus? Love that second photo too
Yep, love the tinnies. The little white one started life as an inflatable, now has a running plank and it sits just like a full size speed boat

[grayson]

My engine is new, have a new head to weld up for increased compression, i have 40 yamaha reed blocks and 50 tohatsu carbs ready to fit. We both fitted CCR reeds, mine have opened up stops and the white boat has rev plates. He has cut tuner, drilled leg and lightened flywheel. It revs very freely, ill post a link in a sec
At the ramp recently
https://instagram.com/p/6bLIE6TQoX/

And here running before any modifications
https://instagram.com/p/tuL7_ozQh8/

[Tiller guy]

My engine is new, have a new head to weld up for increased compression, i have 40 yamaha reed blocks and 50 tohatsu carbs ready to fit. We both fitted CCR reeds, mine have opened up stops and the white boat has rev plates. He has cut tuner, drilled leg and lightened flywheel. It revs very freely, ill post a link in a sec
At the ramp recently
https://instagram.com/p/6bLIE6TQoX/

And here running before any modifications
https://instagram.com/p/tuL7_ozQh8/

Did you buy the racing or sport CCR reeds? How did you open up your stops? Johnson used shims on the little 15hp motors. I thought about trying that on my 30hp.

[grayson]

[QUOTE=Tiller guy;147355]Did you buy the racing or sport CCR reeds? How did you open up your stops? Johnson used shims on the little 15hp motors. I thought about trying that on my 30hp.[/QUOTE
Yes CCR sport Reeds. To be honest on the little 30 they may be a little stiff, thinner or lighter reeds may be better if stock but im going to town on mine so i got them now.
First i put the stops in a vice and bent them to the same shape as a 40 reed stop ( from ebay pictures). I bent one then used it to eyebsll each one after that to make sure they were even. Here is a before and after picture

[grayson]

Tonight i fitted 40hp yamaha reed blocks, they look the same but on closer inspection they have larger windows under the reeds. See picture for difference

[Fastjeff57]

The 70/ 90 hp Yammy uses 6 petal reeds that are only a tiny bit wider. You MIGHT be able to fit them.

Jeff

[grayson]

The 70/ 90 hp Yammy uses 6 petal reeds that are only a tiny bit wider. You MIGHT be able to fit them.

Jeff

Hey cool Jeff! , I'll try these now but there is always later haha. Maybe on the wing boat because he is fitting 50 carbs, and hasn't bought the new reed blocks yet.
Funny the 50 carbs I ordered turned up as 40's, they look heaps easier to fit so I'm going with them.
Just ported the reed plate flange a mm or so to take the 40 carbs last night, now to clean the carbs and play with the linkages

[Tiller guy]

Grayson, Thanks for the comparison! I have the 40hp blocks and the race reeds ready. I was expecting the reed blocks to be the same, but I was wrong. I'm still debating the high compression head?

[grayson]

Grayson, Thanks for the comparison! I have the 40hp blocks and the race reeds ready. I was expecting the reed blocks to be the same, but I was wrong. I'm still debating the high compression head?

We have two heads. One is on the wing boat already. He has has the bowl welded up and ground to shape then cc measured. Mine is at a friends now getting looked at. We will have results in the next few weeks. I was told head chamber shape was more important than compression. I still think it needs a bit more though as its pretty low stock

[grayson]

[QUOTE=Tiller guy;147365]Grayson, Thanks for the comparison! I have the 40hp blocks and the race reeds ready. I was expecting the reed blocks to be the same, but I was wrong. I'm still debating the high compression head?[/QUO

at what stage did you put on the race reeds? did they make a difference? i wonder if they are stiffer than the sport reeds? i have read conflicting things on the net

Here's a pic of me running 4th pin shallow water drive engaged 39mph here. It was actually faster in third pin with shallow water drive but only by maybe 1 mph, just easier to drive.
I have since straightened the bottom, bent reed stops, fitted reeds and fixed a restriction on my prop spacer and run a best of 42 mph. More to come hopefully :cool:

[Tiller guy]

Restriction on prop spacer? What prop are you running?

[grayson]

Restriction on prop spacer? What prop are you running?

i have a worked 13p solace stainless ( cupped, thinned progressive pitch) - it was off my last tohatsu - same splines but i had to make a spacer to fit it on the yamaha, i machined the splines out of an old tohatsu thrust washer - and then later machined down the outer edge - as it was creating a restriction through the hub

[grayson]

I have restocked the 40 tohatsu carbs, fuel pump now in the middle, the vacuum pulse hole seems to work.
I think the choke will work now I swapped around the rods that that hold the choke butterflies from bottom to middle and played around a bit, I will find out tomorrow if it works.
Next job is to shorten the rods for the throttle linkage between all three carbs and try to get the throttle linkage working.
Oh yeah and fix the fuel fitting I snapped off last night

[Tiller guy]

What about the auto lube linkage?

[grayson]

[QUOTE=Tiller guy;147389]What about the auto lube linkage?[/QUOTE

The one that does the throttle? I have to resize the threaded rods and they will fit. Then I gotta find a way to make them connect on the engine

[Tiller guy]

I take it your motor is premix? The oil injected motors have a linkage arm on the other side of the carbs that controls the oil pump.

[grayson]

Yes premix, I think I found an easy solution, if it works I'll post it up in a day or so, fingers crossed

[grayson]

Ok. The fuel pump works after switching the bottom carb to the middle, the choke lines up after switching the rods that hold the choke butterflies on the bottom and middle carb. Just gotta play around with this linkage, i had a roller off an old tohatsu that almost worked perfectly straight up. Cant wait to get it sorted.

[grayson]

Just incase anyone reads this - i've fitted 40hp Tohatsu carbs, the 50hp carbs require more work and the pump doesnt line up

[Tiller guy]

Any test results yet? I remember someone saying the stock yamaha link rod worked ok?

[grayson]

Any test results yet? I remember someone saying the stock yamaha link rod worked ok?

I want to leave my original carbs intact, so have to get that part or similar from a wrecker.
It's running and reving, but it's not perfect ss I have only running it on the trailer

[grayson]

Get an old factory carb and used the roller and linkages. Very happy with the result, have full throttle after a bit of fiddling and will hopefilly run it this weekend. Still need to lengthen the the choke rod but thats a minor job, should run as it is.

[Tiller guy]

Nice to see that the stock throttle link rod works. Good luck on testing! Keep us posted.

[Tiller guy]

The Yamaha 30hp butterfly shaft is a perfect fit. My carbs have 125 jets. I thought 122 was the norm?
http://i1262.photobucket.com/albums/ii617/blindshot75/Mobile%20Uploads/WP_20150918_23_40_18_Pro_zpse92hrgiq.jpg (http://s1262.photobucket.com/user/blindshot75/media/Mobile%20Uploads/WP_20150918_23_40_18_Pro_zpse92hrgiq.jpg.html)
http://i1262.photobucket.com/albums/ii617/blindshot75/Mobile%20Uploads/WP_20150918_23_40_56_Pro_zpsgogryhtq.jpg (http://s1262.photobucket.com/user/blindshot75/media/Mobile%20Uploads/WP_20150918_23_40_56_Pro_zpsgogryhtq.jpg.html)

[grayson]

That is great the rod fits! That will be neater than mine and the roller will be better positioned.

I ran mine today, just a quick two way run, only pulled 41 mph but felt quite a bit more torquey and held a higher maybe 200 more rpm. Stopped and checked the plugs and it was very lean, so I packed it up and came home.
I'm debating weather to drill out the jets or buy some, but I'm not sure where to get them.
I have ordered 132 jet sizes from the 50 but not even sure if they will fit? Local dealer only has standard sizes - 122 or 132 135


Tomorrow morning I will pull out a jet before work and then do some more research.

I think these tacc carbies are made by a Japanese company named Teikei but still researching

[Tiller guy]

My carbs came off of a Nissan NS40D. Same as Tohatsu. The fuel pump on the bottom doesn't work because of the shifter rod being in the way. http://i1262.photobucket.com/albums/ii617/blindshot75/Mobile%20Uploads/WP_20150918_22_44_21_Pro_zpsg8kvfw7k.jpg (http://s1262.photobucket.com/user/blindshot75/media/Mobile%20Uploads/WP_20150918_22_44_21_Pro_zpsg8kvfw7k.jpg.html)

[grayson]

Can't find 125's anywhere!!! Going to drill mine and see what happens

[Fast Fred]

if you are goin to drill them, dill in the direction the fuel flows,

[grayson]

if you are goin to drill them, dill in the direction the fuel flows,
Thanks fast Fred, by any chance do you know where to buy tohatsu jets - like 125 and 140 or bigger?
I'm after 125 and my friend is 140 and maybe bigger

[Tiller guy]

My local outboard shops don't know anything about the jets. One guy told me that my motor will never run right again LOL

[grayson]

[QUOTE=Tiller guy;147560]My local outboard shops don't know anything about the jets. One guy told me that my motor will never run right

I've heard that before!

[DuckLn]

I bot 125 mains for a tohatsu m40d several years ago but i had to look for em. Once you get the manufacturer tohatsu/nissan part # google it. You may have to look at the m50d parts to find em.

[grayson]

I bot 125 mains for a tohatsu m40d several years ago but i had to look for em. Once you get the manufacturer tohatsu/nissan part # google it. You may have to look at the m50d parts to find em.

Thanks, not having a lot of luck. I can buy stock sizes, so if I mess them up I can at least buy more

[Tiller guy]

I found the 125 jets for you grayson http://www.boats.net/parts/search/Yamaha/Outboard/2006%20and%20Later/25MSH/CARBURETOR/parts.html. The newer Yamaha 25hp 2 cylinder twin carb uses the same Teikei TACC carbs and the factory main jets are 125's. Here's a video that shows everything is exactly the same https://www.youtube.com/watch?v=J9ByNu5UPZs

[grayson]

You absolute champion. I ordered them just now.

[Tiller guy]

These look very nice http://www.boatracingfacts.com/forums/showthread.php?9988-Yamaha-30-Head-Project

[grayson]

Good find! Currently in discussions with a friend to reshape the stock head, hopefully we can eventually go billet too

[Tiller guy]

I did my first test run and so far a 3 mph gain. Motor felt rough when gently accelerating, but it ran strong when I hit the throttle hard. More torque for sure and the 125 jets might be a little too much. I will order a set of 122's tonight for testing.
http://i1262.photobucket.com/albums/ii617/blindshot75/Mobile%20Uploads/WP_20150927_18_01_47_Pro_zpszmfzboa2.jpg (http://s1262.photobucket.com/user/blindshot75/media/Mobile%20Uploads/WP_20150927_18_01_47_Pro_zpszmfzboa2.jpg.html)

[DuckLn]

Mine runs great with 125s but they are 40 carbs. I ran 122 vs 125 back to back on the same fuel. Played with timing a smidge with both and had no recognized variance in top speed. Also ran tony doukas reeds vs boyesens on both main jets.

[Tiller guy]

Mine runs great with 125s but they are 40 carbs. I ran 122 vs 125 back to back on the same fuel. Played with timing a smidge with both and had no recognized variance in top speed. Also ran tony doukas reeds vs boyesens on both main jets.

Did you shave the head? I'm running 40 carbs with CCMS race reeds, cut down tuner and 40/50 reed cages. I'm a little nervous about removing the head because it's a saltwater motor.

[grayson]

Mine runs great with 125s but they are 40 carbs. I ran 122 vs 125 back to back on the same fuel. Played with timing a smidge with both and had no recognized variance in top speed. Also ran tony doukas reeds vs boyesens on both main jets.

which reeds did you stay with? did they work better than stock reeds?

[DuckLn]

My engine has been full ported and polished by an accomplished builder. I have a completely custom exhaust tube, 150 psi on each hole, 50 intake, 50 reed cages, and some other stuff including the 40 carbs. Tony doukas was nice enough to send me several sets of reeds in different thicknesses and i did try different timing settings and main jets but never could get em to run any faster than the others. I tried vp race fuel a couple times and even on onxgenaged fuel couldnt recognize an improvement in top speed And that was with the .125 mains. I didnt have any .130 mains or i would have tried em. Its on a 280 lb duck boat and is quick. First one on ghe gas last one off.

[grayson]

My engine has been full ported and polished by an accomplished builder. I have a completely custom exhaust tube, 150 psi on each hole, 50 intake, 50 reed cages, and some other stuff including the 40 carbs. Tony doukas was nice enough to send me several sets of reeds in different thicknesses and i did try different timing settings and main jets but never could get em to run any faster than the others. I tried vp race fuel a couple times and even on onxgenaged fuel couldnt recognize an improvement in top speed And that was with the .125 mains. I didnt have any .130 mains or i would have tried em. Its on a 280 lb duck boat and is quick. First one on ghe gas last one off.

Do you mind sharing what rpm and speed you are getting?

[Tiller guy]

I ran the 122 jets and the motor ran great, but I lost 1 mph. So I re installed the 125's and my idle mixture was off again. I thought it was running great on the hose so I went out for another test and now I'm down 2 mph? I was concerned about losing speed so I did a compression test and it's still really good. My spark plugs got really wet from loading up on the hose with bad carb settings and the motor was missing a little when I did the test run, but it did clear up. Could my plugs be fouled, but still run so so? I will spend more time dialing the mix screws in and use a new set of plugs for the next test run. If this doesn't work I'm buying a bigger motor!

[grayson]

I ran the 122 jets and the motor ran great, but I lost 1 mph. So I re installed the 125's and my idle mixture was off again. I thought it was running great on the hose so I went out for another test and now I'm down 2 mph? I was concerned about losing speed so I did a compression test and it's still really good. My spark plugs got really wet from loading up on the hose with bad carb settings and the motor was missing a little when I did the test run, but it did clear up. Could my plugs be fouled, but still run so so? I will spend more time dialing the mix screws in and use a new set of plugs for the next test run. If this doesn't work I'm buying a bigger motor!
Don't give up yet!

[Xpress2830]

Hey Grayson I found the .122 jets run the best in these little motors with 40 carbs. I had one shortened 30 tuner, 40/50 reed cages with stock reeds, 40 carbs and it ran great. I actually lost RPM with the CCMS reeds. Never tried the Boyesen reeds. I have two sets of cages and some .122 jets if you wanna try...Email me bobby.crochet@lyondellbasell.com...

[Koondog]

Hey Grayson I found the .122 jets run the best in these little motors with 40 carbs. I had one shortened 30 tuner, 40/50 reed cages with stock reeds, 40 carbs and it ran great. I actually lost RPM with the CCMS reeds. Never tried the Boyesen reeds. I have two sets of cages and some .122 jets if you wanna try...Email me bobby.crochet@lyondellbasell.com...

You had a really nice motor Bobby. To bad some thief is enjoying it now. You've got the talent to build another great one for sure.

[Xpress2830]

Hey Ted yeah you right. I am looking for a Tohatsu 25 power head M25C3.

[grayson]

You had a really nice motor Bobby. To bad some thief is enjoying it now. You've got the talent to build another great one for sure.

thanks Bobby i have emailed you

[Xpress2830]

Good morning. I had a 1998 25 3-cylinder on a 1546VJ Xpress. I changed to a 30 tuner shortened at to water inlet, 40 / 50 reed cages with stock reeds, Tohatsu 40 carbs with ( .122 ) hs jets, had to port intake to accommodate the bigger carb ventura, I gave this little motor all the timing I could. Stock motor ran 28 MPH with a Power Tech SRA3 11 pitch @ 5900, modded motor ran 42 MPH @ 6400 RPM with a 14 Pitch Turbo Prop. This is with just me 6 gallon fuel...This little motor woke up with these mods. If you raise compression you won't see too much gain w/o ported block. Good luck hope this helps, Bobby...