2002 islandia speed issues with 1000lbs people

[Gonzo714]

Hi guys new to the forum got A question for you guys the islandia runs great with around 900lbs (persons). If I add another 200 lbs more it will not get up to speed the rpms will go up 6000+ but it will not go past 15mph. If I take them off boat runs up to around 40mph? ( my guess it’s a weight distribution issue but seems really odd). Gas tank full potable water tank is full and nothing else really except some buoys. Currently out on the lake for the remainder of the week any suggestions? Thank you!

 

[nataliator]

I noticed that if I have alot of people sit in the back of the boat it won't get on plane. Just the nature of the boat I guess. I send people to the bow and it planes.

If you want to help your planing regardless of how your passengers are sitting, there is always trim tabs! ($$$) lol

 

[Gonzo714]

There’s no issue with planing and the owner before myself actually added trim tabs it just doesn’t make sense thank you for the response though, getting info from other page they think the impeller/housing

 

[dblackstone]

What is the reason for thinking it is the impeller/housing?

I haven't heard of a mercpowered islandia that didn't have to move 1 or 2 people back to get up on plane when loaded that much.

 

[whodat18]

So have the same exact issue.
With 9 people, coolers and crap, I couldn’t get above 15 mph at 6300 RPM’s
(2 times out on the lake)
However with 7 people, coolers and crap, I can Get 28-35 (choppy water pending and also, only one time, first time we had it on the water with a load since we bought it)
When Its just two of us we run 45-48 MPH and just myself a consistent 48. (Again on clean water) Trim tabs are installed. Is there a special way I need to position passengers and cargo, Trimtabs? Or am I looking at a problem here.
‍‍

 

[TateM76]

I have the same problem whodat18! That's why I'm on the forum. Hopefully someone will help is out

 

[dblackstone]

7 people average weight of 180lbs is 1260 lbs.

Obviously average weight can be a lot different depending on kids.

If the front seating area is full you may just need to move some back.

 

[TateM76]

Yeah i calculated around 1100 lbs for all passengers. I was just wondering if this is how the boat supposed to perform or if I had an issue

 

[whodat18]

Sorry silent.. Been traveling like a mad man and haven’t had a chance to run her again but will this weekend and report. I did adjust my trim tabs to “max flight” meaning tension on the shock spring. I’ll let you know how it goes Tate!!

 

[Tim75]

Sorry silent.. Been traveling like a mad man and haven’t had a chance to run her again but will this weekend and report. I did adjust my trim tabs to “max flight” meaning tension on the shock spring. I’ll let you know how it goes Tate!!

Jet boats, all the way back to the late 1970s, were known to have best performance at or better than 10 pounds (boat+gear+fuel+etc.) per horsepower. You are way beyond that. But that is an extreme drop in performance. Check the leading edges of your impeller and the inside vanes of your stator.