Which Impeller Do I Have?????

[starbuck]

Im trying to figure out about where im at impeller wise. running at 3000 rpms im runnin 32mph on the gps and 50mph at or around 4000. its a 1975 18ft avenger with an olds 455 with berk 12 jc

[Rondane]

Is 4000 full throttle? If so my guess would be AA impeller.

[Riverat84]

yeah same here i dont know what the hell i have....is there any way of telling rather than opening up the whole pump? lol

[YeLLowBoaT]

is your motor runing good??? even a AA @ 4000 is only 239 hp.... now you tach could be messed as well........ BUT if your GPS speedo is right then you would have a AA... and a motor that is not making alot of HP.( all # thanks to JPC)

[starbuck]

no that is not full throttle around 1/2 to 3/4 it still had a lot left

[YeLLowBoaT]

thats good to hear... I was thinking you had 2 or 3 cylinders out... what do you red line at?

[starbuck]

thats good to hear... I was thinking you had 2 or 3 cylinders out... what do you red line at?
if i understand your question correctly im not sure what my rpms are at top speed. I just got this engine built and about 5hrs on it now. Temptations are tough but ill manage..

[n8dawg]

I'll jump in here since your breaking in your engine. I have a 455 olds with a jacuzzi wj. My gps at full throttle reads 65.5mph with the rpm's at 5100.
What size is my impeller?
Thanks

[RICHARD TILL]

Starbuck, you`re 4.5 hours late on knowing what that motor will do. when i run a new motor for the first time i get it to operating temperature and check the oil pressure. if everything sounds right, i go for it. been doing it for 35 years. no failure yet.

[BOOGEYMAN]

I always break them in like I am going to run them!!!! If anything is going to let loose on ya it is usually right from the get go.

[Marlin455]

Ditto- Run it like you stole it right from the start(after cam breakin!) :)

[RICHARD TILL]

when you find out which it is, it oughta be a "B" cut.

[sleekcrafter]

To know what impeller, you have, speed is not reletive at all, the pump if properly loaded, it will spin, the same RPM's tied to a dock, as it will going 90 mph across the lake. To determin what impeller is in your boat you must know the conditon of you pump, and what WOT rpm you are turning. Also verify that your tach is reading corectly, they are known to be off a bit, some times.
Sleek

[GunninGopher]

My Berk has "12JE-A" stamped on an ID plate in the intake housing. I just got the boat and haven't run it. I'm assuming that the "A" is the impeller that at least came stock in the pump. Is that correct?
If yours have such an ID plate and it hasn't been modified, maybe the answer is there.

[SmokinLowriderSS]

you are correct there gopher. The "A" last on the plate is what was orriginally in the pump as delivered new.

[starbuck]

mine says 12JC-A-H whats the H for?

[sleekcrafter]

mine says 12JC-A-H whats the H for?
I have one that is 12JG-A-SS ??? could H mean it was built for Hardin??
Sleek

[GunninGopher]

Well if SS is stainless steel, H is _______________.
I'm only aware of aluminum, bronze, or stainless. I'll bet someone here has the whole story on that. If no one posts, try calling one of the shops, they'll have the answer. Post it here if you do please.
At least it looks like we've determined that the pump was originally boxed with an 'A'. If I changed impellers on my boat, I would modify the ID plate to reflect the current condition by slashing out the "A" and stamping the new one in next to it. I'll bet that you are running an 'A'. Those speeds are about what I've gotten at rpm on the 2 v-hull jet's I've had with A's fi that is any indication (about 30 at 3000).

[SmokinLowriderSS]

30 at aprox 3,000 is in line with my Taylor, depending on water and load of course. A bit faster if I can run light and a touch of up diverter, maybe 33 or so with a slight ripple on the water. Any chop & it slows me at that speed.
I've always run an "A" since new so looks like that's my best SWAG (Scientific Wild A$$ed Guess).