|Last time out I went from having 1200lbs of ballast in my sportstar, to 2100lbs. This made a HUGE difference in the wake and I definitely don't want to go back to what it was like before. However I noticed that at riding speeds we were now at 3000 rpms instead of the usual 2500 rpms. Will this cause any problems in the future?|
|what...like your gas card balance going to the moon? |
you're working the engine harder than before, you should expect it to not last as long. change the fluids on schedule and don't ignore signs of stress (oil burning, running hot, terrible gas consumption).
|I wouldn't worry too much about the engine, it just has to work a little harder, but it should be up to it. |
The transmission is another story. It has to work harder too. Especially the "hit", getting that much weight up on plane.
You should also be concerned about what all that weight is sitting on, and how it impacts the hull. If you are using fat sacks, then the weight is fairly well distributed, but if you are using lead bars be very careful that the bars are not beating down into something vital.
|Keep on top of your oil changes, monitor tranny levels, you should be fine.. I'm running 1100 lbs stock, 2 - 600lbs in back, and 2 - 275 lbs in front, 2 - 65 leadheadz, + riders almost 3000 lbs and 3700-3800 rpms. She likes it! And a topped off tank 57 gallons.|
|It will work your engine harder, so make sure you are propped right if you are normally running under that load, otherwise you will lug the engine and that will seriously shorten the life. You will want to verify that with your typical load that your boat at WOT is in the middle or upper end of the RPM range specified in your manual for your boat.|
|Of course its going to be harder on the engine and tranny. But what I was told awhile back is that the trannies are pretty much the same as you find in large ocean fishing boats that handle more weight than that with no ballast. My uncle's old 89' Nautique 2001 went through years of running with alot of weight all the way up to almost 900 hours with no problems.|
|What signs of distress or trouble would you "look" for in a transmission? |
Also, how do you know if you're "propped" right?
I'm running a 4 blade OJ that came with my '02 X5.
|David - With your typical load in the boat, you run your boat at WOT (Wide Open Throttle) and note you high RPM reading. You want your boat to read at the upper end of the range specified for your boat. Typically that is between 4400-4800 RPMs and goes up to 5000 or 5200 for MPI motors (check your engine manual). If you are not close to the upper end of the range, you need less pitch on your prop to get your motor to turn faster. A prop shop can adjust that, or you can buy a new propeller that is a better pitch for your current needs. For example, I gave my old OJ prop to Bronson Propellers and told them to add 200RPM. They did exactly that and now my boat races out of the hole and hits about 4700RPMs at WOT. This makes your engine work at peak efficiency and gives you max power out of the hole and better top speed.|
When you say 'run at WOT at your typical weight', it sounds like you're talking running with ballast and people. Not sure I'd be really comfortable running a boat certified for 1400 lbs payload at WOT when loaded with 1500 lbs water plus the equivalent of six adults.
I've heard from several sources that the single biggest boat engine killer is too much prop for the boat - my v-drive tops out (empty) at 43 mph while turning 5500 rpms - well short of the 6000 rpm redline. The OJ guys showed their concern over that but recommended against bringing the prop pitch/diameter down.
|Why always the WOT measurement? I don't care at all about top speed, but am more interested in what's good for the engine at boarding speed while weighted down. Wouldn't the best thing for the engine be to run at peak torque at boarding speed (whatever rpm that is)? (Obviously, I am no mechanic, but seems to make sense to me.)|
|Setting your prop right at WOT is the perfect way to get your engine/prop combo right for boarding speeds. I'm no mechanic either, but I do know this gets your engine operating in the peak torque curve at the lower RPMs. It also ensures that you will not over-rev your engine.|
|It's no doubt that it'd be better for everything (except maybe mileage) if the engine was propped for wakeboarding speeds. I think that most of you guys are already there though. I could stand to raise mine from ~3100 to maybe ~4000 because the Lexus likes to rev and if the truth be told, needs a little help in the torque department. |
The trouble you run into is as Bruce says - if you're empty and not paying attention, you'll run out of prop and hit the rev limiter (if you've got one.)
Although lugging the engine (as if 3,000 is lugging..) is bad for the motor, it's great for mileage. Bring the RPMs up and I thnk you'd trade mileage for reduced wear. And if you got radical with the reprop, you could be really screwing your cruise.
|My X5 is pushing out of the hole at 3000-3200 rpm regardless of weight and it gets sluggish when I have close to 2000 lbs. |
There seems to be some disagreement on what I should do, but it sounds like at least a slight lowering of the pitch will help and not hurt too much.
|Derek - Don't mean to be countering everything, but lugging will actually give you worse fuel economy. I still insist on what I said above. That is basically straight out of the Indmar manual. Lowering your pitch is likely a good idea, but you need to know your RPM reading at WOT first. If in doubt, call your MC dealer. They deal with this all the time.|