30 HP Yamaha with 50 hp Tohatsu 50 Carbs

**grayson** · 09-22-2015

You absolute champion. I ordered them just now.

**Tiller guy** · 09-24-2015

These look very nice http://www.boatracingfacts.com/forum...0-Head-Project

**grayson** · 09-25-2015

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

**Tiller guy** · 09-27-2015

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.

**DuckLn** · 09-28-2015

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** · 09-28-2015

Originally Posted by 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.

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** · 09-30-2015

Originally Posted by 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.

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

**DuckLn** · 10-01-2015

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** · 10-02-2015

Originally Posted by 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.

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

**Tiller guy** · 10-11-2015

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!