SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: shellgetoverit on April 07, 2008, 04:56:19 PM

Title: my bbc is crap wont rev
Post by: shellgetoverit on April 07, 2008, 04:56:19 PM
can anyone help me...sooo i bought my little 21 footer last year...found out the motor was bad...starter bolt broke off in the block and other nonsense that the guy hustled me into...needless to say i rebuilt my motor .30 over 454 blah blah holley 750 curled water injected logs and im not sure on the pump except its a berkley... anyway i took my boat out yesterday and the darn thing wont rev over 3k when its in the water...put it on the trailer it reved to ablmost 5400 i am at a loss as to what to do i assume my timing may be off or my jet is phucked any info would be super as im about ready to hang a 300 merc off the back
Title: Re: my bbc is crap wont rev
Post by: 429heads on April 07, 2008, 06:26:10 PM
I would check your pump , and how long did you run motor on trailer , was the pump any good before, what pump is it? was water temp OK and oil pres OK and what pump water  pressure did you have on motor, did pump pull good.what speed did you get to? I hope some of the jet boys jump on this, And help you out.
 :banghead: come guys help him out :o
Title: Re: my bbc is crap wont rev
Post by: FORKEDUP on April 07, 2008, 06:30:19 PM
what happens at 3k, does it fall off, pop, sputter, starter miss firing or............... ??? what is your timing set at, base or total, just trying to get more info that i know the gurus on here will want/need
Title: Re: my bbc is crap wont rev
Post by: BOOST on April 07, 2008, 07:00:12 PM
what happens at 3k, does it fall off, pop, sputter, starter miss firing or............... ??? what is your timing set at, base or total, just trying to get more info that i know the gurus on here will want/need
To much water going though the motor ?
Title: Re: my bbc is crap wont rev
Post by: VAMI on April 07, 2008, 07:23:09 PM
We need more info on the engine cam size,intake,heads,comp ratio,vacum secondaries????????did it spin up before you rebuilt it
Title: Re: my bbc is crap wont rev
Post by: hotrod56cars on April 07, 2008, 08:09:45 PM
A copy and paist on a similar question... MikeF and Oldsquirt are the authors...

What's your total timing at 3000 rpm?

Is the throttle cable adjusted to allow the carbs to open fully?

Are the secondaries even opening?

Are you sure the tach is accurate?

What speed did you see at 3300rpm and how does that compare to speed before this work was done?
Title: Re: my bbc is crap wont rev
Post by: speedymopars on April 07, 2008, 08:27:11 PM
can anyone help me...sooo i bought my little 21 footer last year...found out the motor was bad...starter bolt broke off in the block and other nonsense that the guy hustled me into...needless to say i rebuilt my motor .30 over 454 blah blah holley 750 curled water injected logs and im not sure on the pump except its a berkley... anyway i took my boat out yesterday and the darn thing wont rev over 3k when its in the water...put it on the trailer it reved to ablmost 5400 i am at a loss as to what to do i assume my timing may be off or my jet is phucked any info would be super as im about ready to hang a 300 merc off the back

What impellor? If its an A2-4, you may not be making enough HP to turn it, esp if you put a higher duration cam in it (IE the engine starts making power at 3500 - but at 3K the lines cross and it can't spin it any faster). What MPH are you running at 3K? Did it rev higher before you rebuilt it?
Title: Re: my bbc is crap wont rev
Post by: crewchief22 on April 08, 2008, 12:04:17 AM
Are you getting any vibration?  I've had a rock inside the grate area and at idle would run fine, start pulling rpm and the rock would pull up into the impeller and cause all kinds of havoc.

We definately need more information as to what it is doing to give you a better idea where to start.
Title: Re: my bbc is crap wont rev
Post by: jim brock on April 08, 2008, 08:19:57 AM
could be a tooth off on your cam timming
Title: Re: my bbc is crap wont rev
Post by: hotrod56cars on April 08, 2008, 08:53:41 AM
Could be bad gas.  :banghead:
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Title: Re: my bbc is crap wont rev
Post by: TIMINATOR on April 08, 2008, 11:03:21 PM
Call me, or bring it by and I'll look at it for you. I'm on 107th.ave and Thomas. No charge for the look-see! We do engines and pumps here in-house, so I can get you pointed in the right direction.  TIMM  623-877-8553   9-6 M-F and 9-1 Sat.
Title: Re: my bbc is crap wont rev
Post by: hotrod56cars on April 09, 2008, 09:03:15 AM
Call me, or bring it by and I'll look at it for you. I'm on 107th.ave and Thomas. No charge for the look-see! We do engines and pumps here in-house, so I can get you pointed in the right direction.  TIMM  623-877-8553   9-6 M-F and 9-1 Sat.

Do this suggestion first!
Title: Re: my bbc is crap wont rev
Post by: shellgetoverit on April 17, 2008, 02:56:05 PM
thanks gents im gonna take it out today and fiddle with it and prolly tomorw i will give tim a call and see whathe can suggest thanks to everyone who responded lol my little squirt is a big pain in the A$$ haha thanks all ill let you know how it goes
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