Yamaha 130 V4 Project Build.

[Mr. Demeanor]

Chris is your shaft tapered or same diameter all the way down. If it is I would recommend resplining it instead of welding it. Both can be done still in the lower.

Stan carson

Stan,
Its a tapered shaft so it will have to be cut and welded or sleeved. Interested to hear the pro's/con's of sleeving it vs. not. Seems sleeving it would easier and keep it straight during welding but is it as strong?

[Mr. Demeanor]

All else the same.....

30 x 15 Performance Propellers Performer SC at 92mph rock solid.
32 x 15 Performance Propellers Performer SC at 94mph np problem but a liitle looser.
30 x 15 Performance Propellers Performer SC at 85-91mph like riding a donkey on an ice rink.

I may bolt the motor straight to the transom with the short mid. Ill lose 1-1/2" of setback, 20 pounds of jackplate, and can run the motor a hair lower. Ill have to see how things line up but I know it liked going from 4" setback to the 1-1/2" I have now. The weight savings plus moving 300+ pounds forward even just 1-1/2" would be a BIG change. It would definitely float flatter and launch better.

[baja200merk]

i like the idea of a bigger gear BUT..... Changing gear is not the same as changing whats on the prop shaft.

300lbs ~2" forward is not going to offset the gear. The tunnel tab might help though

[Mr. Demeanor]

The only thing the bigger gear will let me do is run a smaller prop which has less transom lift. Theres a reason you dont see props (a very few exceptions) above 34 pitch. They stop acting like screws and start acting like paddle wheels. More of their energy is transmitted into lifting the propshaft than pushing it forward. Think about as an extreme example of what a 100 pitch prop would look like. Your boat would just spin in circles.
Tim Hackney warned me that the 34 would feel very different and in my boat a little change is very noticeable.

On a side note, I did get wet today...

I was having trouble getting up on plane. Pulled the cowl off while floating to fiddle with the low speed mix and timing. Next thing I know Im going over the side of the boat with the cowl in my hands....
I held onto the cowl not wanting it to sink and Im trying to swim with a nose full of salt water. Im splashing about when I realize I can stand up. Its only about 3' deep

Dago was there and for once didnt have his GoPro rolling. In 25 years of boating its the first time I have fallen out of a boat. 6'3" 225 pounds holding a cowl over my head falling out of a 13' boat had to look hilarious. You know people die falling in a ........

bath tub

[baja200merk]

The only thing the bigger gear will let me do is run a smaller prop which has less transom lift. Theres a reason you dont see props (a very few exceptions) above 34 pitch. They stop acting like screws and start acting like paddle wheels. More of their energy is transmitted into lifting the propshaft than pushing it forward. Think about as an extreme example of what a 100 pitch prop would look like. Your boat would just spin in circles.
Tim Hackney warned me that the 34 would feel very different and in my boat a little change is very noticeable.

Yes and yes but big (36+) "pitch" works. Especially when everyone uses the unicorn aka "theoretical number" aka slip%. Realistically pitch is also a guesstimate. The 34 performer you sell was 4mph faster at 6k rpm then my 36 is at 6100. If I wasnt going to the keys I'd be ordering another one

The gear is torque multiplication. Theres a reason merc doesnt put 1.62 on their 3.0 fishing boat motors. It really hurts it off idle/ mid range and I promise not 1 ODBA racer used a 1.62 at jasper. Point being you going from 2:1 to 1.8 is going to hurt bottom end/mid range. Every time I see your boat run it jumps up on plane with no problem but you said the 34 made it near impossible. With the back to back, same day gear swaps I have done (same prop/boat/motor/temp) the bigger gear only made holeshot it worse. I've been wrong before but if it hates a 34 with 2:1 its going to have the same problem with a ~30p and a 1.8ish.

You know the boat way better then anyone on the interweb but when we swapped cases at the boat ramp on my brothers v4 it was painful getting on plane. Just sharing what I've seen trust me I hope yours hops up and pulls 100+

Dago was there and for once didnt have his GoPro rolling.

Im texting him for the pics tomorrow. We will get a performer before the keys

[Mr. Demeanor]

I dont have a 34 Performer if you need one soon. The 34's are about 4-6 weeks out :-(
Mine is going to MRCRSR for testing on his 21 Skater or I would let you spin it.
They are very popular.

Just to say it out loud...I dont have to go faster. 94 was just fine. I wanted to try a 34 and I did. I absolutely believe it would have went very fast if I stayed in it and didnt die. It went 91mph at about 6500 rpm and was still pulling.

Forgot to mention this is how I got it on plane. One blew out before I got back to the dock. Redneck exhaust relief plugs

[Mr. Demeanor]

I dont have a 34 Performer if you need one soon. The 34's are about 4-6 weeks out :-(
Mine is going to MRCRSR for testing on his 21 Skater or I would let you spin it.
They are very popular.

Just to say it out loud...I dont have to go faster. 94 was just fine. I wanted to try a 34 and I did. I absolutely believe it would have went very fast if I stayed in it and didnt die. It went 91mph at about 6500 rpm and was still pulling.

Forgot to mention this is how I got it on plane. One blew out before I got back to the dock. Redneck exhaust relief plugs

[CharlieN]

The only thing the bigger gear will let me do is run a smaller prop which has less transom lift. Theres a reason you dont see props (a very few exceptions) above 34 pitch. They stop acting like screws and start acting like paddle wheels. More of their energy is transmitted into lifting the propshaft than pushing it forward.

On a side note, I did get wet today...

Dago was there and for once didnt have his GoPro rolling.

There must have been someone else around with a camera, dang. not worth falling out if no one can see it happen.

My comment on gearing are thoughts of a big change, Yes to your thought of a little bit more gear as fine tuning what you have in hand.
My thoughts are more in line of starting over, something like a 1:1 ratio spinning a short prop, drag style. The short prop spinning fast will not be a paddlewheel when you are up at speed.

[Mr. Demeanor]

The gear swap is one of those things I may try. See what happens. Can always go back.
Right now I am just stoked about having a 13" motor pretty soon. I took some measurements and bolting the motor right to the transom with the new mid I can get it on and end up 1/4" lower than where I am now. That should be really close to perfect. Yamaha has slots at the bottom engine mount bolts and I am thinking maybe slot the top as well to give me more fine tuning. When I have it right, make some shims to go in the slots on each side of the bolt with a fender washer to keep them in place.

[Mr. Demeanor]

A preview courtesy of photoshop
Really changes the look of the boat.

Attachment 297740 Attachment 297741

[CharlieN]

Can you use flat shims on top of the transom?

[Mr. Demeanor]

Can you use flat shims on top of the transom?

We will see. Im sure there will be some McGuyvering

[CharlieN]

Depending on how high the engine sits from the top of the transom you might make a set of plates with jackbolts that are captured under the engine allowing for safe and simple adjustment with slotted upper mount holes.

[Mr. Demeanor]

Depending on how high the engine sits from the top of the transom you might make a set of plates with jackbolts that are captured under the engine allowing for safe and simple adjustment with slotted upper mount holes.

I like that. I would have to make sure the engine bolt holes through the transom are well sealed coating the inside of the holes with epoxy to seal the wood core. If I ma going to be loosening and adjust using the main motor mount bolts they are not going to stay sealed well during testing.

[CharlieN]

Obviously not for salt water use but the bolts could be inserted with the threads out. This would allow sealing the bolts with say 5200 which would also reduce the need for holding the backside. I know it is frowned upon to have the nuts exposed to the water.
Where your boat gets washed each outing this may be an option.