Top Speed Issues

[Nick Hughes]

I posted in another thread last weekend about how I wasn't getting close to the advertised 50 MPH. And since I wet slip my boat, that cleaning it was probably the issue. So after being in the water for 2 months, i pulled it out. It was dirty, really dirty, the algae was like hair on the water line. And below the water had what looked like flower heads 100s of them, looking like spiders, black. So i took Mary Kate On and Off to the hull. Did an ok job, might use 100 muralic acid next time. Took 3 passes of spraying and scrubbing to get it off. At $20 per bottle, it takes 2. Was able to get most of the hull clean, except near the center of the hull under the bunks. The driveway at the lake house is stone and not easy to lay on my back underneath. So anyways, drastic improvement, but still a little dirty. And Ive got what appears to be some sort of calcium like deposits on the jet outputs. I didn't have my power washer up there, but will next time. So anyways, i was at 35 MPH before cleaning and about 42 after. Does it still seem likely that with more cleaning i will gain that extra 10MPH? I saw someone mention about the California emissions. I do have a low emissions sticker that was on my hull, is that it or how else can I tell? From the boat ID? I bought it new from a dealer in MN. 42 feels insanely fast, but would love to experience what is advertised.

 

[Rob9550]

I have a 2015 with the California emissions and I was able to get to 48 mph with a full tank, coolers, 6 people and the bimini up. If you are only getting to 42mph you may have another issue.

 

[Evil Sports]

That happened to my 1996 Nitro bass boat when I left it in the river for a month. I could feel it struggling to get on plane with the usual amount of power. Short answer is yes all that growth on the bottom can really slow you down. Best to find a place that you can lift your boat off the trailer and fully clean the bottom at least 1x per season or dont leave it in for so long.

 

[mraz72]

I was/am in the exact same situation as you. It is a PITA to clean while on the trailer, and I think you have to be really careful with acid around the trailer, not entirely sure.

I was at 33mph, cleaned the hull with Star Bright hull cleaner (sprayed it on with a garden sprayer, power washed it off) and got back to 42-48mph. My issue is heat soak, which happens with the supercharged motors.

For your case with the twin engines, maybe it has to do with altitude? Maybe you didn't get all of the crap off the hull?

I would get it professionally acid washed after this season is over, and next year, first thing, try to hit 50

BTW, with the product I used, I literally sprayed it on and washed it off. I didn't scrub, and I didn't get way underneath between the bucks either...

 

[Nick Hughes]

Wow, i had to scrub like crazy. So either the product you used is crazy good or the funk on my boat was crazy bad. I keep my boat at Indian Lake, says the elevation is 1263ft. I wouldn't think that would be a factor.

 

[Matt Phillips]

besides growth on the hull and mechanical (how efficient are your pumps running, tides, current, how high are the waves today, wind, elevation, load in the boat will have an effect on performance. I was on Lake Tahoe last weekend with 7 people on the boat, 1/2 load of fuel, waves at about 2-3', 15 MPH winds. Going into the wind at 8k rpm got me about 22MPH. Coming back the other way 30 minutes later at 8k for me upper 20s.

 

[mraz72]

Yeah, my growth was no where near that. What was strange was the before and after pics of me using that product don't look at that different. The only way I could tell that anything really happened was the hull FELT a lot smoother.

I had no grass growing though lol

 

[Julian]

When my old boat was dirty it would drop to 35, and then after a complete cleaning (marina lifted in sling) it would return to the 47-49 mph range.

 

[Nick Hughes]

Curious what a marina sling session runs you? I imagine at that point I just pay them to clean as well.

 

[robert843]

[QUOTE=" I saw someone mention about the California emissions. I do have a low emissions sticker that was on my hull, is that it or how else can I tell? From the boat ID? I bought it new from a dealer in MN. 42 feels insanely fast, but would love to experience what is advertised.[/QUOTE]

On top of the engines somewhere should be an emissions sticker if it has three stars that is the normal model if it has four stars that is the ultra low emissions and if you have that model the top speed if probably closer to 46-48 instead of 50.

 

[Glassman]

Check your speed with a good GPS.
42 mph may be a bit off, the speedo has an adjustment feature behind the dash.

 

[Nick Hughes]

I'll check the emissions sticker and do GPS speedometer when Im back up at the lake on Sunday. The Waze iPhone app has a speedometer, is that accurate?

 

[Nick Hughes]

So I've got a California emmisions model. Not sure if I really care, but I do. But I also noticed that WOT both engines were just about 7000 rpm. Should they top out at 7600?

Lost my console cover today too, I feel that's a poor design and probably won't replace it.

 

[mraz72]

I sucked up a rope and lost a shoe today, if that makes you feel any better lol

The RPMs do seem a little low....

 

[Noko]

So I've got a California emmisions model. Not sure if I really care, but I do. But I also noticed that WOT both engines were just about 7000 rpm. Should they top out at 7600?

I bought my boat from MN and it was River Valley Power and sport. They sold me a CARB boat and didn't disclose it. I think thats pretty poor on their part. They were nice to work with otherwise. My boat rpms top out at 7,600 port and 7,800 starboard. I have hit almost 50mph but I easily get 46-48mph with it. You should be getting better than 7,000 rpm.

 

[Julian]

Curious what a marina sling session runs you? I imagine at that point I just pay them to clean as well.

That was them cleaning it in their sling! $13 a foot.

 

[Nick Hughes]

Should I change the plugs? I'm just about 20 hours and will be doing my first oil change this week. Doubt that's causing it.

 

[robert843]

If its the California model the top speed fully clean loaded with people and fuel is likely only around 45mph and with a lighter load around 47-48mph. 50 mph is even tough on the non California Models sometimes. Today I had 3 people and a full tank of fuel and barley hit 50 mph and it took about 2 minutes of wide open running to get to that speed.

 

[Gym]

Wow, i had to scrub like crazy. So either the product you used is crazy good or the funk on my boat was crazy bad. I keep my boat at Indian Lake, says the elevation is 1263ft. I wouldn't think that would be a factor.

@Nick Hughes. Your altitude at 1263 in itself isn't the only elevation factor affecting your rpm & speed. The temperature, air pressure and humidity at that elevation can play a big role in engine performance. For instance. Your elevation of 1263 on a 70 degree day with normal air pressure gives you a density altitude of 2566 feet above sea level and at 80 degrees the density altitude is 3193 feet. Your engine operates with density altitude not actual altitude. The higher the density altitude the less oxygen in the air for the engines to burn. If you get a chance to do a sea level run I believe you will get closer to the advertised max speed. Don't forget manufacturers post max performance using ideal conditions. A standard day is 59 degrees at sea level with a barometric pressure of 29.92 hg.

 

[Speedling]

Why not trailer the thing? Never had any scum on my boat i couldn't hot sauce off after each run. Unless it was kid problems. That kinda scum is usually harder to get rid of. Keeps coming back, asking for food, arguing, spilling things, etc.