xb21 bassport

[rifles11]

i hav hydrotec motor with yamaha lower it does not like even with the pad or half inch below should i go deeper does anyone hav info on yamaha lower or torque master experience

[Tim Powell]

With the SHO the stock gearcase is proven to blow out at the 85 mph mark on the xb21...id assume your phase motor would have similar results with the stock gearcase. With the amount of HP you are making I would want nothing but a sportmaster. The boat should handle better with the sporty as well.

Is your gearcase stock or did Wayne modify it?

[scj]

Yamaha case has too much lift built into it. Try running an over the hub prop before you lower below 1/2" under.

[rifles11]

the only thing wayne did to it was block off side water inlets and moved to the bottom of case

[rifles11]

this is what it feels like im running down the lake at around84 to 87 then all the sudden the front feels like it falls and heads left

[xb03fs]

I am not a scientist or Yamaha expert. FYI my boat does not like 1/2" below or anything below with a sportmaster and a mercury either. The boat becomes a handful at those low motor heights. Mistakingly running 1/2" too low had me thinking I had forgotten how to drive earlier This year. The boat was handling terrible.

I think* that if the shape of the Yamaha case is wrong getting it higher out of the water would decrease blowout. Lower would make things worse...as it puts the water more on the case..I feel out boats run safest at even to 1/4" above at lower speeds and safest at high speeds 1/4"-3/8" above and 1/2" above provides best speeds. However that is where low speed lift seems to be going away. Since I precisely measured my motor heights I have not tried much higher. For me I do not feel 1/2" above is a set it and forget it height, but 1/4" above could be.

Just my thoughts. Maybe try, maybe don't. Maybe someone more knowedable can chime in.....

[Tim Powell]

With 10" setback I am able to run as high as 1" above with a 2 man tournament load. The OP is running a 10" plate as well if I remember correctly.

I'd be no lower than even with the pad and really be closer to 1/4-1/2" above at all times.

[scj]

With the low water pick up installed, I'd raise it to even but I would still try an over the hub prop

[rifles11]

ok steve from hydro dynamics came over to my place at the lake just for fun we dropped it down to 1.25 below pad , it ran 91.3 with 30 promax 1.75 gears at 6200 rpms ,this lake not long enough to much traffic but at least i finally got over 90 thanks for all the info, im goin to have to go sportmaster lower steve told me i was on the edge with this lower unit at that speed