Baja 242 islander low rpm and top speed
08-06-2019 | 02:57 PM
#1
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Baja 242 islander low rpm and top speed
My dad recently bought a 2003 Baja 242 islander with a 6.2 mx mpi. It has a rev 4 17p 14 5/8 inch prop on it. The wot rpm is supposed to be 4800-5200 rpm but with it trimmed very high up and completely wot we could only get 4400 out of it. Trimmed any higher it would ventilate. This also only pushed the boat 43 mph, we expected a 55 mph boat. Is this the speed we should be expecting, is the prop too aggressive? Any help is appreciated.
08-06-2019 | 03:10 PM
#2
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when it vents does the rpm rise accordingly? Have you calculated your prop slip on BBlades prop slip calculator? Is your tach reading correct? Have you GPS'd your true speed?
Typically Bajas do better with a 3 blade mirage + prop. On the 242 Id do a 21P mirage Plus. 4 blade is a bunch for your motor to handle at upper rpms.
Typically Bajas do better with a 3 blade mirage + prop. On the 242 Id do a 21P mirage Plus. 4 blade is a bunch for your motor to handle at upper rpms.
Last edited by Cerberus66; 08-06-2019 at 03:28 PM.
08-07-2019 | 03:23 PM
#3
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Your data is incomplete. What is the drive ratio? Is the speed GPS? Without that data it is hard to offer advice.
Assuming the speed is GPS and you have a 1.5 drive ratio the speeds are on par with what I would expect with that motor and prop combo. That prop is an excellent prop, but perhaps not the best for your application. Does it get on plane very easy or does it labor somewhat?
I would NOT goto a 21" Mirage just yet. I would recommend a 19" three blade (Mirage or Laser II) for starters then see where you are at.
Assuming the speed is GPS and you have a 1.5 drive ratio the speeds are on par with what I would expect with that motor and prop combo. That prop is an excellent prop, but perhaps not the best for your application. Does it get on plane very easy or does it labor somewhat?
I would NOT goto a 21" Mirage just yet. I would recommend a 19" three blade (Mirage or Laser II) for starters then see where you are at.
08-08-2019 | 12:36 AM
#4
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From: Omaha/LOTO
https://www.topspeed.com/boats/baja-...r-ar43139.html
Something is definitely off. Are you at a high altitude?? It probably came from Baja with a 21-23 Mirage Plus prop.
Have you had the engine checked to make sure its not down on power??
Something is definitely off. Are you at a high altitude?? It probably came from Baja with a 21-23 Mirage Plus prop.
Have you had the engine checked to make sure its not down on power??
08-08-2019 | 10:30 AM
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Your data is incomplete. What is the drive ratio? Is the speed GPS? Without that data it is hard to offer advice.
Assuming the speed is GPS and you have a 1.5 drive ratio the speeds are on par with what I would expect with that motor and prop combo. That prop is an excellent prop, but perhaps not the best for your application. Does it get on plane very easy or does it labor somewhat?
I would NOT goto a 21" Mirage just yet. I would recommend a 19" three blade (Mirage or Laser II) for starters then see where you are at.
Assuming the speed is GPS and you have a 1.5 drive ratio the speeds are on par with what I would expect with that motor and prop combo. That prop is an excellent prop, but perhaps not the best for your application. Does it get on plane very easy or does it labor somewhat?
I would NOT goto a 21" Mirage just yet. I would recommend a 19" three blade (Mirage or Laser II) for starters then see where you are at.
The speed is taken from a gps. I’ve been trying to figure out the drive ratio. Is it printed somewhere? The boat also planes pretty easily.
