Slow to plane, great top speed?

[volvo3.0]

Seems I may have a carb issue but unsure, all my past carb issues were from not enough fuel, but perhaps this one is actually running rich when planing?
volvo 3.0 glp-c , I/O
boat is a 2004 18(think its actually 17.8') foot crownline 180
No visiable damage or buildup under the boat
fresh water only


My symptoms...
cranks good when cold, idle is slightly low but not terrible. Once warm, idle is around 800.
Anything under 3000rpms then going full throttle doesnt bog, just takes foever to get past 3000, then runs great. Top RPM is 4300, which is a tad low from what I gather but I didnt trim fully, so probably another hundred of 2 of RPM's would be possible with a longer run. 42mph@42-4300rpm, which, seems pretty normal, maybe even slightly better for this configuration of 18 footer with a 3.0. Backing off the throttle slowly to try to get on a plane easier doesnt seem to change anything. With 2 kids in the rear seat, I dont think it will plane at all, no matter how long. When they move to front of boat, it is still slow to plane(maybe 20 seconds or so)
Boat did set(in storage) from 2013 until this year. I removed all old gas, new pump filter and carb filter. New plugs, cap and rotor. Oil change also(not that that is my issue)
Prop is a 14.25x23

Like I said, Ive had issues before of a carb being plugged in some area, causing it to be hard to plane but it never ran great once on a plane. Could this possibly be a carb issue? I have a OEM carb rebuild kit on the way, just trying to get my head wrapped around this before tearing into the carb incase theres a seal(or something) that could cause this.
Thanks in advance, if more info is needed, I can provide

 

[Sea Rider]

Welcome to Iboats,

Some issues :
What's the max wot rpm range factory stated, how loaded do you usually go boating with ?

Happy Boating​

 

[Bondo]

Prop is a 14.25x23

Ayuh,.... Welcome Aboard,..... A 21" prop will probably give ya better results,.....

 

[volvo3.0]

Max RPM says 4200-4600
Its usually just me and gf and 2 younger kids. However it does the same thing even with just me, it does plane faster but still an obvious issue

And I agree on the 21 pitch prop, I think that would be the perfect prop

I should have stated, but this boat is SOLELY for island hopping on my local lake, we dont wake, ski, pull tubes, nothing. We only cruise, I normally go enough rpm's from take off to get on plane, usually that is maybe half throttle and then I cruise around 32-3500 rpms. The "new" boat runs great once it planes

 

[KRichmond]

I would check your TPS - throttle position senor near the MAF. my OMC 5.8 would do something similar. It took 1 minute to get on plane then would procced to "near" top speed". Felt like I had 75% power. Some TPS can be adjusted if you have slots for the two mounting screws. You can turn 1/8" and retighten, then try a hole shot. Some use a chainsaw file to open up slots for the screws to slide. I just bought a new TPS. Now the computer is in sync and adds more fuel for a proper WOT, especially from a hole shot.

My butterfly would open all the way but the old TPS didn't recognize properly and wouldnt give the amount of fuel it need to really rev out.

I have a 95 Four Winns with 351W or OMC 5.8. At first i checked the oil pressure and water temp sensors in case it was trying to go to limp or Slow mode. The cheater fix for that is a tan wire with black strip. Also one in the ECU pin 24 i think... Anyway that get you out of limp mode but it also bypasses they safeties, so best to not unless its a emergency. Hope this helps.

 

[KRichmond]

Max RPM says 4200-4600
Its usually just me and gf and 2 younger kids. However it does the same thing even with just me, it does plane faster but still an obvious issue

And I agree on the 21 pitch prop, I think that would be the perfect prop

I should have stated, but this boat is SOLELY for island hopping on my local lake, we dont wake, ski, pull tubes, nothing. We only cruise, I normally go enough rpm's from take off to get on plane, usually that is maybe half throttle and then I cruise around 32-3500 rpms. The "new" boat runs great once it planes

Did you end up finding the problem?

 

[Bondo]

I would check your TPS - throttle position senor near the MAF. my OMC 5.8 would do something similar. It took 1 minute to get on plane then would procced to "near" top speed". Felt like I had 75% power. Some TPS can be adjusted if you have slots for the two mounting screws. You can turn 1/8" and retighten, then try a hole shot. Some use a chainsaw file to open up slots for the screws to slide. I just bought a new TPS. Now the computer is in sync and adds more fuel for a proper WOT, especially from a hole shot.

My butterfly would open all the way but the old TPS didn't recognize properly and wouldnt give the amount of fuel it need to really rev out.

I have a 95 Four Winns with 351W or OMC 5.8. At first i checked the oil pressure and water temp sensors in case it was trying to go to limp or Slow mode. The cheater fix for that is a tan wire with black strip. Also one in the ECU pin 24 i think... Anyway that get you out of limp mode but it also bypasses they safeties, so best to not unless its a emergency. Hope this helps.

Ayuh,..... No tps, he's got a carb,....

 

[Senior B]

The 3.0 of course is no power house and lacks torque which will be amplified even more when over propped a bit. You are in the low end of the RPM band, but as mentioned earlier, a 21 will do you better, get you to the high end of the RPM band and you'll notice the boat getting on plane quicker.