Baja 240 Poor Performance

11632 Views 34 Replies 21 Participants Last post by rick.reece1969, 7 mo ago

2ez4me

Discussion Starter · Jan 9, 2008

Last winter I purchased a 1990 Baja 240 It had a stock 310 hp 454 w/ a 17 pitch aluminum prop The boat would not plane out with more than 2 people in it and had a top speed of only 48 mph I changed it to a 20 pitch 4 blade SS It didn't help much I installed a custom Comp Cam, Comp roller rockers, dual plane intake, @ a set of large oval port heads ported & redone by my local engine builder The stock bottom end broke 2nd time out I had a forged 496 stroker short block built w/ 9.5 pistons It was the end of the season & didn't have time to dyno I would think this thing should make 500 hp The boat tops out at 61 mph on the gps @ 5300 rpm w/ a 26 pitch prop & has a tough time getting on plane w/ little weight in the boat. It still struggles to pull a wake boarder out of the water w/ a 1/2 tank of fuel and 4 people in the boat w/ the old 20p 4 blade prop Guys w/ stock 350 mags run circles around me this sucks! Whats wrong here?

21 - 35 of 35 Posts

2ez4me

Discussion Starter · #21 · Jan 10, 2008

Reflooring the boat would be a good winter project Any advice on how to do this would be appreciated

Super24

· #22 · Jan 11, 2008

Zen_Nemo said:
I had a '91 240 with the 454 Mag in it. The prop was a Mirage Plus 21 pitch worked over by Houston Propeller and would run 68-70 all day long.

Either that was before the dawn of GPS or you were turning some serious RPMs!

PachangaSS

· #23 · Jan 11, 2008

Unless Houston Prop tweaked it up in pitch...?

Super24

· #24 · Jan 11, 2008

PachangaSS said:
Unless Houston Prop tweaked it up in pitch...?

You would have to turn a 22" prop to 5600 RPMs to see 70. That's assuming 10% slip which is unlikely with that setup.

I heard Houston Prop does great work but the math doesn't add up.

Not trying to be a jerk, just trying to give some realistic exectations.

Mkos1980

· #25 · Jan 11, 2008

Whats an average amoutn of slip. I put my stuff into the calculater. 4600 RPM's 21 Pitch Speed 55.1 and they said realistc speed should be 62 something and it gave me 11% Is that bad or good?

Fyhr Factor

· #26 · Jan 11, 2008

Mkos1980 said:
Whats an average amoutn of slip. I put my stuff into the calculater. 4600 RPM's 21 Pitch Speed 55.1 and they said realistc speed should be 62 something and it gave me 11% Is that bad or good?

I believe 11% is considered good.

Zen_Nemo

· #27 · Jan 14, 2008

Super24 said:
You would have to turn a 22" prop to 5600 RPMs to see 70. That's assuming 10% slip which is unlikely with that setup.

I heard Houston Prop does great work but the math doesn't add up.

Not trying to be a jerk, just trying to give some realistic exectations.

It wasn't before GPS, best GPS was, if I remember, 69.8. So you are correct, I was off .2mph. Great day for it, low humidity, downhill with a tail wind.

pork chop

· #28 · Jan 20, 2008

How do you check a tach, do you just hook up a second one and compare the two or is there a way of testing them?

MarkyMark

· #29 · Jan 20, 2008

a decent timing light will do it.

Super24

· #30 · Jan 20, 2008

A merc scan tool should be able to verify a tach too.

bajabob 600

· #31 · Jan 21, 2008

here wt i would do get hand held gps hook a diffrene tack if tack is rigth you should do 72 mph if you number are on now you boat sitting in water looking at side 4in from lip so about 24ins showing to engine hach i had to replace the wood on egine hach back seat floor in middle seats above gas tank they rot and water lod try to lift egine hach by it self see if it real heavy i replace wood painted with 2001 interlux expoy primer 8 years still solid no rot my boat 480 hp 150 drive 25 p prop 70 mph 3 blade prop work best for top speed

MarkyMark

· #32 · Jan 21, 2008

Super24 said:
A merc scan tool should be able to verify a tach too.

assuming it is EFI. timing light works on all.

dcg9381

· #33 · Jan 21, 2008

Zen_Nemo said:
I had a '91 240 with the 454 Mag in it. The prop was a Mirage Plus 21 pitch worked over by Houston Propeller and would run 68-70 all day long.

Put a 21-23p prop on it for starters.

As posted above, your prop slip is way too high.

I'd start by using an INDUCTIVE tach on your plug wires - and test your speed by GPS.

If you're slipping that much, your boat is too heavy... I'd bet it's more likely that your tach isn't properly calibrated.

I've got a 23.5 foot boat, 385hp mag 454, it runs a 23 pitch from the factory. I still think it can do better at 11% slip.

detideoneon

· #34 · Jan 22, 2008

When I had my 240 and I would get water over the swim platform and hatch if I came off plane to fast. This boat sits very low in the water. It has a built in swim platform which sits water level.

I had a stock 454 and had no problems getting on plane with a 22p 4 blade.

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rick.reece1969

· #35 · 7 mo ago

shaken knot stirred said:
Wow water coming over the hatch now that doesn,t sound right under any condition,if he is waterlogged can he fix by drying it out over a period of time or does he have to rip out all the wood?

I have a 1991 Baja 240 hole shot sucked! I ended up pulling out the floor and the stringers, all we rotted! When I pulled out all the saturated foam it weigh 900lbs! I have replaced stringers floor and foam . Just finished the fiberglass and painted the inside. I’ll be in the water haulin butt soon

21 - 35 of 35 Posts

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