Pros and cons, tips and tricks - Berk 12JC

[core attitude]

For those of you running this pump or with intimate knowledge of it, can you share your experiance for improved performance of this model. I would also welcome the pros and cons of it before I find out for myself. :)
Thanks,
Pete

[core attitude]

Bueller? Bueller?

[miller19j]

I have asked similar questions and have not received any responses besides take it to……..he does great…….
I think that there are very few people that work on their own jets so finding people to answer this question is a hard one. I am planning on rebuilding mine this winter and have a few ideas on what I would like to do. I am no expert and have no idea what the result will be. But this is my plan.
1 Rebuild jet (replace all seals and bearings)
2 Tighten up tolerances ( mount new impeller on shaft and turn down and true up to match wear wring. I am not sure what clearance I want to run but I am thinking somewhere between .020 and .025)
3 Polish Bowl and intake ( Go though the bowl and smooth all the casting marks and rough edges)
4 Reduce exit nozzle diameter ( I am not sure if I am going to do this or not, Still have some research to do)
5 Polish and powder coat outside of jet (It might as well look nice)
Like I said I am no expert but this is my plan.

[core attitude]

Thanks miller19j, I'll check back for updates on your progress. I've seen reference to a $2.00 upgrade, do you know what it is? (might as well start cheap :D )
Pete

[miller19j]

core attitude:
Thanks miller19j, I'll check back for updates on your progress. I've seen reference to a $2.00 upgrade, do you know what it is? (might as well start cheap :D )
PeteCan of spray paint?

[Jungle Boy]

Us river boat guys use bondo filler to smooth out the intake and fill in the bottom of the clean out cap inside the pump. I have spent hrs die grinding the inner bowl viens smooth with no speed increase. The biggest gains have come from swapping out impellers and finding the correct amount of wedge that lifts the boat the best. We don't use Place Diverters so the wedge makes big gains or losses. Sometimes a shoe ahead of the intake will make good gains on how the boat rides and pump pressure, but this takes lots of time and effort to find the right combination. Trial and error basicly. :cool:

[core attitude]

Can of spray paint? No wonder it's such a closely guarded secret!
Jungle Boy, why no diverters?
Pete
[ September 27, 2002, 12:11 PM: Message edited by: core attitude ]

[Jungle Boy]

[Jungle Boy, why no diverters?
Pete[/QB][/QUOTE]
They tend to get beat up. The nozzles we use are a steel hand made type that can take a good whack and not fall off.

[core attitude]

Got it, thanks.
Pete

[Bense468]

You cannot wedge a C bowl. You need a split bowl for that a b or a g. The G bowl is the better split bowl. The C bowl is a good bowl also. All intakes are the same pretty much except for a few like the e and so forth. If you are buying a new bowl I would look for a g bowl so you can add a droop or wedge it. But the c bowl is a great bowl also and the veins are a little longer for a better flow. I have heard of people splitting their c bowls by having them cut. Don't know if I would do this or not. If you definatly want a split bowl I would just go with the g bowl.
As far as performance, there are a few extremes you can go. It all depends on your whole setup. What type of boat, what motor you are running, what your plans are etc. For a river boat I would just tighten up the pump, depending on HP put a stainless impellar or if it is lower hp just go with the aluminumn. Get a good shaft. YOu can have the impellar and bowl worked if you would like but on a river boat where speed is not your 1st concern it really is not worth it. Last but least call someone like Jack at mpd of any other good pump builder and just talk to them. See what they have to say. Good luck
[ September 27, 2002, 02:50 PM: Message edited by: Bense468 ]

[core attitude]

Thanks Bense468, I like the options of the g bowl but I'll just have to weight my options once I get into the pump a little and see what it's going to cost to sruce it up.
Pete

[Builder]

woops

[spectratoad]

I just had my JC rebuilt by a guy here in town and it seems to run alot tighter. He put an A impeller in for me and blueprinted the jet. I think he said he put a new wear ring in and got it to a closer tolerance than stock. I put a new grateon with the shoe to help shove more H2O. It seems to run a little faster, couldn't find my GPS last time I was out, and just seems to be more responsive in general. He also said the only diff between the J & G was the bowl and that a G bowl would bolt right on. I didn't ask how the interchangeability is from the nozzle out for the place diverter etc... I run a stock 460 in my Spectra 20. Not much info as far as your original questions for upgrades but hope it was some info for ya.

[core attitude]

spectratoad that's great, I just want to hear what's working for everybody so I can maybe spend a little less time getting set up right. Thanks for the input.
Pete