250 Sport XS on the GrandSport

[TBuck2003]

Whipper. I've had the extra weight of the 3.0L power plant since I bought the boat new in 08. It really runs better in slightly choppy water and with a passenger. Had it out Saturday but the lake was packed and didn't get to string it out yet, it's still in break in mode so just taking it easy. I've got to try some bigger wheels because my 28 QIV-OT Hydromotive slips like crazy out of the hole. Seems like it needs a prop with larger blades. Ran it last week with a 28 Trophy plus to 92.5 and that was at 5600rpm. This beast has a lot left in her. At 92.5 it was on a rail until I trimmed it up another bump and that was when it fell off the pad and took a hard right turn. My son was in the passenger seat and he looked at me and said dad what just happened, I told him I just found out how high I could trim it. Weather here has sucked lately but next week we will be back on the water finishing the break in process and hopefully stretching it out a bit. Just think I don't have enough prop for top end yet.

Scott,
You need a block off ring put on your 28 OT. That will stop the slippage out of the hole. You will then most likely need SPVS holes in prop (Single) to adjust for hole shot. There is a lot of torque and exhaust coming through that beast !!! Easily fixed...

 

[harrells]

Todd, glad you chimed in. Here is the deal. I had the blow-out ring on the 28 QIV-OT and it wouldn't even plane off 1800rpm's is all it would turn and just plow thru the water with the nose in the air trimmed all in. Do you think I need to add larger holes and put the ring back on, Also do you think a little cup would help also. By the way it's a 1.62 gear.

 

[GotMyAlly]

You ought to be able to turn more prop than that....I bet you end up in the 29" - 30" range.

 

[TBuck2003]

Todd, glad you chimed in. Here is the deal. I had the blow-out ring on the 28 QIV-OT and it wouldn't even plane off 1800rpm's is all it would turn and just plow thru the water with the nose in the air trimmed all in. Do you think I need to add larger holes and put the ring back on, Also do you think a little cup would help also. By the way it's a 1.62 gear.

Yes the large holes being the SPVS that accept the Merc. plugs. That will loosen it up enough for sure !!

 

[whipper]

My wife says go ahead for a 250 or 300xs so Im shopping around. Im tired of not being able to ski and tube or just slow cruise for hours when the lakes rough with wake boats. The old promax has one speed wot. The new motors can run any rpm and stay cool. Ill like that. At 20-25mph the GS can handel any cop. But after a while it needs to speed up to cool. i hate that.

Harrells whats new with the setup if anything. Tryed any differant props? How comming of speed normal when done slow?

 

[harrells]

Whipper, haven't had it on the water in the last 2 weeks due to the weather. It has rained here almost every day all summer long. Hopefully this coming weekend we will have a chance. As for props I just bought a 29p Q IV-OT with pvs holes from a fine gentleman on this board and I have a blow-out ring to attach to it that will make a good ski and tubing prop for the kids. Don't think it will be my top end prop but we'll see how it works before I look for any larger wheels. And for slowing down at high speed the only time I've done that was day one when we hit 92.5 and I trimmed it up too high and it did a little wiggle from the sten and I knew what was about to happen and I completely chopped the throttle and it took a hard right, but that was my fault and now I know when to stop trimming it up. But before I hung the new 250 I did have a stock 200 3.0L and have chopped the throttle at speeds of over 80 mph and it would just settle right down. Good luck with your search. I decided on the 250 as opposed to the 300 because you don't have to use premium gas.

 

[whipper]

Thanks for the response. I was thinking the same thing with the primium gas vs 87 oct. In the near future that will be even a bigger expense running the 91. The main reason I was thinking 300 was because of the DBR mods. Im sure he will be making some for the 250 also soon enough? They will most likely require 91 again even on the 250 perhaps? The main thing I wanted was the rasied limitter to 7000. Im sure i wouldnt {need} the 300 ponies anyway. As our hulls dont like going past 105 any way. I also really like the idea of a Taylor 15 inch mid with a 2.5 SM with the 250 or 300xs. If I could find a good low hour 250 or 300 out of warrantee and maybe just raised the limitter and add the 15SS and 2.5 gerar set along with the Mike nass cowl that would be good also.

 

[whipper]

Check this out! Very cool.http://www.abc.net.au/tv/newinventors/txt/s2919202.htm

 

[fnshrmaster]

My wife says go ahead for a 250 or 300xs so Im shopping around. Im tired of not being able to ski and tube or just slow cruise for hours when the lakes rough with wake boats. The old promax has one speed wot. The new motors can run any rpm and stay cool. Ill like that. At 20-25mph the GS can handel any cop. But after a while it needs to speed up to cool. i hate that.

Harrells whats new with the setup if anything. Tryed any differant props? How comming of speed normal when done slow?

Does the Promax get hot when towing? How hot and how long can you run it pulling?

 

[silverbullet02]

I've never had a problem pulling anybody. Only time mine gets warm is somewhere in that 1-2k rpm range.

 

[DOUBLE J]

Whipper, I would forget the idea of raising the limiter to 7000 on a 300xs. That motor runs the best propped out around 6200. I have a 300XS on my Checkmate 2400 with the Simon mods( lightened flywheel, pop-it valve, tuner and remapped computer). To be honest just do the lightened flywheel and forget the rest. Been there , done it and the most notable difference is the motor spins up faster due to the lightened flywheel. Save the $'s on the rest and put it toward the Taylor mid or the Nass cowling. I personally would go for a 300XS over a 250 XS due to it being the same weight. I also run premium in all my motors so the octane level is mute to me. I'm not going to spend that much on a motor to save .25 cents or so a gallon. I look @ higher octane as extra insurance in the hot summers I have down south where I live. Just my opinion....

 

[Lotus 50]

I run premium in all my motors because for us, premium can be ethanal free (at some stations). My Promax runs hot at high load low rpm, like running just on a plane with the nose tucked in rough water. Everywhere else it's good. Water pump or normal?

 

[whipper]

I run premium in all my motors because for us, premium can be ethanal free (at some stations). My Promax runs hot at high load low rpm, like running just on a plane with the nose tucked in rough water. Everywhere else it's good. Water pump or normal?

Well thats been my issue for 8 years David. To the point i dont ski anymore or any thing but run fast. So I would say normal. If its rough as the lakes get inidated with tow boats these days this gets worse. You cant really comfortably run 40+ over 3-4 ft rollers all day and ya cant run 20 for very long were ya need to be to be comfortable. pluss as ya heat up and need to run ya cant because the lake has no sections to do it in the mid day. Sound about right?:big grin thats why Im going BB. The new power can run at any rpm all day long. If ya want to run 20 around the lake when its rough pulling a tube no problem abd sip fuel doing it. Ya want to take spin to 90 no problem. Wouldnt even need a prop change from skiing.

 

[whipper]

Whipper, I would forget the idea of raising the limiter to 7000 on a 300xs. That motor runs the best propped out around 6200. I have a 300XS on my Checkmate 2400 with the Simon mods( lightened flywheel, pop-it valve, tuner and remapped computer). To be honest just do the lightened flywheel and forget the rest. Been there , done it and the most notable difference is the motor spins up faster due to the lightened flywheel. Save the $'s on the rest and put it toward the Taylor mid or the Nass cowling. I personally would go for a 300XS over a 250 XS due to it being the same weight. I also run premium in all my motors so the octane level is mute to me. I'm not going to spend that much on a motor to save .25 cents or so a gallon. I look @ higher octane as extra insurance in the hot summers I have down south where I live. Just my opinion....

Duelly noted. Thanks. I can only get 91 octain on the lake anyway so the 250 would have 91 in it also. The marine gas is all 91 and cheeper than 87 at the pump so as you say its not an issue for me either way 300xs. Im really likeing the 250HO also with a 16 taylor and a 1.62SM? i would have to say the merc 300xs is what Im leaning on more because of a few reasons.

#1 Cheeper to find used. $10000.

#2 More mods available.

#3 Mike Nass cowl is sick!! and none for E-Tech Makes Merc lighter.

#4 15inch useing same gearcase shortened. {even less center of gravity than 16} Also comes with a 1.62 SM were I would have to buy a 1.62SM to run the HO $$ then shorten it as well.

#5 The Merc with a 15 talor mid and MNass Cowl just looks plain from the future!! One just like this please....

 

[Darth VMAX]

300 ETEC

Thats what I want on a 21' A-Boat ;-)

 

[xb03fs]

I want 200ROS xb21 on mine if money is no object....

 

[xb03fs]

I want 200ROS xb21 on mine if money is no object....give me 7000 rpms and 1.87's and run me down.

 

[whipper]

I ran against a 200 ros on a 19ft Cougar a few weeks agao. Nice guy but he wasnt to inpressed with the power. He was running a little over 80. I smoked him with the 225.:beer: He did like it better than his old 2.4 though. Very quite. A 300 on a 21 would kick a 200ros in a bad way I would think? Espesualy a 300 with a light fly wheel and a 32 pitch prop.

 

[whipper]

300 ETEC

Thats what I want on a 21' A-Boat ;-)

There just so expensive. I like the E-techs also just cant afford one. You can make a 300 merc 350hp 7000rpm with a carbon cowl and 15 inch for the same price as a stock 300 e-tech.:banghead

 

[tcs719]

Whipper my 225 pm was doing the same thing as you spoke of earlier. over heating low rpm. I had my motor rebuilt this past winter. I asked the builder why it was doing that. He said it was a seal going bad in the motor. After rebuild it does not do it any more. It has not got over 140. Hope my remark does not ruin the possibilities of a new one with wife!