XB21 SHO Owners ?

[PSM207]

Anyone running a 250 SHO on an XB-21? I'm in the process of buying an XB-21 ProSport and rigging it with a 250 SHO and I'm curious of setups and performance.

[JMCasper]

I don't know if Steve, sji, is still on the board he had a 2+2 with a flashed 200 hp Yamaha. He could probably help out. I have that boat now but he put back the original Mercury Pro XS 250 before I got it.

[Mrbuck50]

His username is SCJ. He still lurks on here. I’ll let him know.

[bottomfisher]

Allison should be able to give tons of setup help. They had A BASS Elite Tour Pro Grant Goldbeck running one with a stock 225 SHO.

I also know that Hydrotec does a modification to the factory lower unit so it can be raised higher on the transom without losing water pressure. I think they offer solid mounts as well.

[hooken203]

I had one. XB21 Bassportpro. Lower unit mods will be needed. Solid mounts maybe. The fact that you can flash the ecu or better yet supercharge it is a big plus. HydroTec should be able to help you out a bunch because they have had several years to work on it. Not sure what kind of performance help you will get out of Allison because Darris never thought this engine was a good idea on these boats. He told me he would not run that boat to it’s full potential with that engine on it. Due to soft mounts and the lower unit but that was several years ago.

[scj]

My recommendation for using a SHO on the XB-21 is to buy the 200 hp model. It’s exactly the same engine as the 250 except for the stickers and ecu programming. The 200 saves you about $2k and saves you a bunch on insurance. Take the $2000 and have HydroTek flash your ecu and install solid engine mounts.
HydroTek offers a low water pickup modification for the stock gear case but it’s pricey; around $1400 but that was several years back. Not sure what Wayne charges now.
I only ran two small gauges on my dash; one for fuel level and the other for the Jack plate height. Everything else was viewed through my graph.
My 200 dyno’d at 338 hp at 7000 rpm’s but it was no where near as strong as the new 4 stroke Mercury’s. It had a flat spot around 6100 that killed pulling the boat into the 90’s with a big prop. One thing to note is my SHO was the very first SHO ever dyno’d in the US. Wayne had the Yamaha guys there watching as it was all new. I’m sure HydroTek has figured out the dip in the power curve but I haven’t talked to those guys in 3 years. I think they were working on cam phasers the last we talked.

HydroTek installed a 3L 1.62 sportmaster gear case on my SHO which looked factory installed; no spacers or adapters are required.
I was very happy with my setup and I could sprint from zero to low 90’s in 17 seconds fully loaded.

Funny how when you mentioned 4 stroke back in ‘15, everyone said just buy a 300 2 stroke. All those guys are now either enjoying their new Mercury 4 strokes or they want one. Times change.
Running the SHO on your Allison requires a different hot foot and a couple different shifter parts compared to running a Mercury. Allison has what you need.

Another thing, a stock SHO gear case is going to blowout in the mid 80’s on a xb-21. Never ran Wayne’s low water pickup version so I cannot comment on that one.

[PSM207]

My recommendation for using a SHO on the XB-21 is to buy the 200 hp model. It’s exactly the same engine as the 250 except for the stickers and ecu programming. The 200 saves you about $2k and saves you a bunch on insurance. Take the $2000 and have HydroTek flash your ecu and install solid engine mounts.
HydroTek offers a low water pickup modification for the stock gear case but it’s pricey; around $1400 but that was several years back. Not sure what Wayne charges now.
I only ran two small gauges on my dash; one for fuel level and the other for the Jack plate height. Everything else was viewed through my graph.
My 200 dyno’d at 338 hp at 7000 rpm’s but it was no where near as strong as the new 4 stroke Mercury’s. It had a flat spot around 6100 that killed pulling the boat into the 90’s with a big prop. One thing to note is my SHO was the very first SHO ever dyno’d in the US. Wayne had the Yamaha guys there watching as it was all new. I’m sure HydroTek has figured out the dip in the power curve but I haven’t talked to those guys in 3 years. I think they were working on cam phasers the last we talked.

HydroTek installed a 3L 1.62 sportmaster gear case on my SHO which looked factory installed; no spacers or adapters are required.
I was very happy with my setup and I could sprint from zero to low 90’s in 17 seconds fully loaded.

Funny how when you mentioned 4 stroke back in ‘15, everyone said just buy a 300 2 stroke. All those guys are now either enjoying their new Mercury 4 strokes or they want one. Times change.
Running the SHO on your Allison requires a different hot foot and a couple different shifter parts compared to running a Mercury. Allison has what you need.

Another thing, a stock SHO gear case is going to blowout in the mid 80’s on a xb-21. Never ran Wayne’s low water pickup version so I cannot comment on that one.

SCJ
Thanks for the info. I recently made a great deal on a low hour SHO 250. I've spoken with Hydrotec in the past as well as recently. Not sure about a lower unit mod at this point in time. I'll stay in touch as this progresses.

[ndh78]

Feel free to contact me for my $.02

Great motor but I would definitely put in the solid mounts.

[PSM207]

Feel free to contact me for my $.02

Great motor but I would definitely put in the solid mounts.

ndh78 - I sent you an instant message.

[walnutshoe]

I would strongly suggest full Hydrotec lower mods and solid mounts from the get go. The mods make a night/day difference on performance boats running at or above pad.

[Tim Powell]

I would like to get my hands on one to test. I would definitely want Waynes new LU mods or sporty conversion. The stock SHO lower will blowout.