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gmocnik
06-26-2001, 01:03 PM
any thoughts or suggestions welcomed..
engine is a blown 502 (5lb boost) in a 21'hallet...pump was a jacuuzi y pump...did the american turbine "energizer" kit two years ago...added the inducer pump last year..
i have been through three impellors (aa cut)in a year..the leading edges look like someone took a "bite" out of them...
boat normally pulls 5200 rpm when pump is fresh...
whats up???? current pump mechanic is stumped...this time he is putting in a "different manufacturers" impellor....
thanks in advance

spectras only
06-26-2001, 01:32 PM
The area you're boating must be full of rockfish http://free.***boat.net/ubb/biggrin.gif,sorry about your deal with your impeller,but I only see this problem when people pull up at a beach where the bottom is pebbled. I shut the engine off and coast in when I'm boating in such area.

gmocnik
06-26-2001, 01:52 PM
nope....no rockfish
very carefull about that ....

77_Tahiti
06-26-2001, 02:19 PM
I just heard that even in 6 foot deep water you can suck up rocks pebbles, etc. According to Steve up at Panther Jet Drives we should be keep our feet off the gas when in 6 foot or less water. Bottom line do not stomp on the peddle or you could find the rockfish. http://free.***boat.net/ubb/eek.gif

Jim
06-26-2001, 10:14 PM
you must be running a alum, empeller,with a blowers motor you need to run a ss empeller or a bronze empeller. Jim Brock

Blown509Liberator
06-27-2001, 04:56 AM
Jim is right on here. Go to a SS impeller. Blower motors will eat up Aluminum ones.

daboot
06-27-2001, 03:50 PM
gmocnik, ck. and see what the average substance is on the river bottom and see if it coralates to your impell. damage, also ck. and see if the veins are broken off at the leading edges or do you have poreous cavities along the leading edges and starting to work there way back. If there working there way back, you might be showing signs of heavy cavitation spin possibly. 77 Tahiti stated not running in 6 ft. or less of h2o, 6ft. is within reason, Just make sure your not running full hog in anything less than 4 ft. KNOW YOUR LAKES/RIVERS, or invest in a depth gauge with low water sound-off function like me, little salty, $150-300 depends on quality of unit, but great little buddy to have with ya man !!!!

spectras only
06-27-2001, 04:25 PM
I also use a dash mounted depthgauge,and yes you can go to as low as 3 feet without picking up pebbles "at idle speed".An aluminum impeller should be good to 500HP,above that I would recommend bronze or stainless.I know boats that ran over 5 years with aluminum imp/500HP without failure,and boats with cavitation and cracking problems after a year with less power.

Slick
06-27-2001, 04:40 PM
The comment on a SS impeller is right on. You're probably at or close to 600hp. At the very least you should be running a bronze impeller. Does your mechanic specialize in jets? A lot of guys in here recommend Jack McClure @ Marine Performance Designs. Give them a call. Someone in here probably has their number.
Last but not least, What kind of benefits did you notice after putting on the inducer?
Thanks Slick

MellowYelloW
06-27-2001, 05:08 PM
hey i was wondering what is a good compression ratio to run when using a blower. and what is the difference between the 8-71 and the 6-71? thanks
brian

Blown509Liberator
06-28-2001, 06:21 AM
MellowYelloW
First off, I run a 509 With 8.6:1 Cr and spin a 6-71 at 6-7 psi I have aluminum heads. Littlefield and my Eng. Builder B&B Performance in Redding CA claim it will live on pump. But I am a little hesitant on that. I am a Automotive Technical Instructor for Bosch and hope to get one of there knock sensor to work on this blower motor to give a audible warning to knock. I will let you all know how this works. Difference in an 8- 71 to a 6-71 well a 8- 71 will move more air. to better understand a 6-71 basically means it was for 6 cylinder 71 ci per cyl Diesel so a 8 -71 is for 8 cyl 71 ci Diesel. etc...etc.. Blower where air pusher for Diesels and where not made to compress air but bolted on smaller Gas motor it was just a side affect and work well for making more HP. Mine with a 8MM belt and sticking out of the engine cover just look and sound so Cool!. if you want to see my boat go to this link there is also a link for a spec and dyno sheet on my motor there. http://nothinbutjets.homestead.com/Liberatorpic.html
[This message has been edited by Blown509Liberator (edited June 28, 2001).]
[This message has been edited by Blown509Liberator (edited June 28, 2001).]
[This message has been edited by Blown509Liberator (edited June 28, 2001).]

gmocnik
06-28-2001, 07:54 AM
thanks for all the inputs....
current pump mech has replaced the eaten impellor with "another manufacturers" impellor..
i asked about stainless and he said it wasn't necessary......i will give it one more chance.....i suspect (as several of you suggest) that there is some excessive cavitation going on....i don't run in shallow water....i don't think my 5lb boosted 502 is putting out more than 600 h.p. either...
i put the inducer in after the last impellor destruction...it definitly helps in the hole shot and does not impair the top end...
thanks for all the responses...
gary

Slick
06-28-2001, 08:46 AM
Isn't that the whole reason for putting in the inducer. It's supposed to load the impeller with 20% more water than the impeller can use thus reducing cavitation (so I'm told) by up to 90%.
Just what I've heard
Slick

MellowYelloW
06-29-2001, 03:58 PM
thanks blower...so i strong motor built with 8-1 would work with a blower.??
my current 454 is about 9.5-1...is that too much?
thanks
brian