Gary P

Double Rigged - We definitely did not hit anything. There was no bump or anything visible. Lake was smooth, nothing in the water, we were only running some old fuel off to make room for fresh fuel for the next days poker run. No bump felt, just started as a wobble in the rear, as if we lost the steering. Within a second or two, we were spinning sideways, backwards, sideways, etc! Thinking back, it seems like it all happened in slow motion, but I can assure you, it did not. Hell of a ride, and darn lucky to not have flipped. I got up to check, expecting to see the steering rams broken or missing, but no, the lower unit was gone.... missing!

Anyway, I've spoken some more to my brother about this.... He said the splines were damaged, actually some were missing, along with the center section and lower unit. I thought that would just mean a new crank, (plus center and lower unit) but he wants a total rebuild. When I asked about the cost, he was told the parts and labor would be well over half the cost of a new 300XS, so it would be better to go with new. My bad, I initially thought he was told it would be more than a new 300. I understand him not wanting to spend 70-75% of the cost of a new one on a used repaired engine.

I've sent him the info on the used motor posted here, as an alternative. But, a pair of big Verados, if they come out with 400 hp versions, would certainly entice him.

SS930

Other than the weight and LU reliability issues with a 400 hp 4 stroke, I would imagine there would be a huge difference in price... probably in the order of at least 2x over a new 300 Opti.

For a light weight cat, I personally would stick with a 2 stroke. If he's looking for a little more power over the 300 XS, going with a set of used 300x engines would gain him a few mph over the Opti's. I believe Merc is still offering the new and/or rebuilt 300x short block should you need to replace a bad 300x engine.

Gary P

Like you're mentioned, the pricing is probably much higher, especially if they ever do come out with a 400 Verado. Also you stated, weight is a big concern, which is why he wouldn't be interested in the 350 Verado. He told me for a 4 stroke and the weight difference, it would need to be in the 400 hp range to make up for the weight penalty.

My brother is fairly conservative (but he likes speed) and is looking for reliability. Up here in the north the season is short enough, without having to deal with down-time. Knowing the lower unit limitations of the sportmasters is a concern. He's had a few failures with them. He had similar problems when he ran a RIB with twin 250's on it (sportmaster lower units). That was an 86 MPH "rubber raft". (What a blast to drive, kind of like motocross on the water!)

The 300 XS's run so nice and clean, and are very good on fuel too. We average approx 2 MPG's at speed i the cat, which is pretty darn good. I have to admit, I don't know much about the 300X. Never had one, or rode with anyone with them. The only thing I've heard is that they are fast. (Which is good!)

He's got a few months to make a decision, and get prepared for 2015. Boating is over for us this year....

SS930

From what I've seen the 300XS runs a little cleaner (smells less too for the same reason) and gets about 30% better mileage. It also seems to idle a little better, but with that said I've seen some 300x engines that idle extremely well. I believe the X has about 20-25 hp on the XS, it's noticeably more powerful... usually a few mph faster. The X is also a little lighter.

Gary P

http://www.davebushracing.com/mercur...0x-update.htmlI've been poking around, looking up the 300X and 300XS, and found this from Dave Bush Racing:

Interesting read. What do you think???

SS930

If reliability is a major concern, a lot of guys say to stay away from modifying the X/XS. With that said, I've seen a couple of guys on S&F have had good results with the DBR and Simon upgrades for the XS. Then again, I also read on OSO recently a member installed the DBR kits in his XS's (on a 30 spectre maybe?) and saw no increase in speed.

turbo rr

iTrader: (3)

Is he running vent kits on those sportmasters? If not that might be his problem. I still am confused about the full rebuild on that 300xs that had the lower unit failure.

Gary P

Turbo - Vent kits? Never heard of them. You've got me thinking - Not that I am aware of.... Are they an external item? I've seen nothing that would indicate there is a vent kit. Interestingly, on one lower unit, it always took a lot longer to fill with lube than the other, as if there was an obstruction. It had been taken apart more than once over the years, and nothing ever found wrong. Maybe the vent kit would have helped???

The full rebuild was because it was much more than just a failure of the gearset in the lower unit. When the lower unit was broken off, it also took the center section (well, some of it, it was physically snapped off), and other 'missing parts'. After closer inspection, there was damage to the splines on the crankshaft, several splines wiped out. Parts and labor were estimated to exceed the value of the engine.... Hence, my brother is considering a full replacement instead of rebuilding this one.

lightspeed

i got a pair of 2011 300xs motors 4 sale one with 47 hrs the other 142hrs

turbo rr

iTrader: (3)

There is a widespread problem with the sportmasters. It goes something like this......Under high rpm the fluid pushes out a seal and then sucks water witch compromises the fluid thus damages the lower unit.....a vent kit stops this from happening. It is a common fix for that problem. Do a search for sportmaster vent kit and you see. You guys definitely need it if you dont have it.