Witchcraft boat

[Witchcraft]

I bought a 18' 1976 Witchcraft boat this past winter. It has 455 olds with a Jacuzzi yJ Jet. Motor runs good (all stock) except headers. Turns well over 5400 RPM. Runs around 50+ mph. How do I tell if it is a worn pump or the impeller that allows more RPM? There is no place diverter or loader grate. I am new to Jet Boating, would either of this items help? Does anybody know anything about Witchcraft boats?

[montrone]

I used to have a 21 Witchcraft with an Outboard 225 hp black max this screamed 75+, no jack plate or any thing good, just ss prop.
but from what i herd it tends to get stress crack's in the back corners of the boat, this could be due to to much power the boat can't handle, or to much hard bouncing, i had crack's bad on the back of mine.
I recently purchased a 25 Sleekcraft with a olds 455 bored .60, and it too has the Jacuzzi 12YJ kit pump.
I called American Turbine http://www.americanturbine.com/
talked wiht (Ron) and asked him how well would this pump handle, he said, just because you got the kit it should perform pretty good. but not 100% like the turbines, he said this pump (Jacuzzi) with out kit is not all that great.
I am not sure if they make the place diverter for our pumps yet, when i e-mailed place diverter.com and asked them, they mentioned they don't have any for this pump. i sure someone does, but that's what they told me? and from what i herd, yes it should help with performance the place diverter.
this is my 1st time to owning a jet boat.
also what kind of heads do you have on your olds? i just purchased C heads off ebay.com and was told form the person i brought them from, and the olds website, these are the heads to have on this kind of engine the best. i use to have J heads which are somged heads and they suck.
also this engine has some common probs. do not push this engine more than 5500 rpm known to blow heads gaskets, why? this engine tends to trap the oil in the heads with out letting back out and causes it to get hot, also make sure you have an 10-11 qrt oil pan this will help.
where are you from?

[Witchcraft]

I believe mine are the K heads. I live in Eastern Iowa. Still waiting for some warm weather.

[montrone]

you have good heads, marine heads

[Witchcraft]

Is there an easy to see what shape the punp or impeller is in? Is there an inspection cover? The boat seems to run pretty good, but seems to turn high RPM's pretty easily. Some people have said that this could be because the pump is worn or the that the impeller is an A.

[Jetmugg]

If your 455 Olds is turning 5400 rpm's at 50 mph, then there is no doubt about it, your pump is worn, no matter whether it's an A or B. (Most likely it's an A) The clearance between the wear surface and the impeller is most likely worn excessively from passing sand, dirt, etc. through the pump. My best advice is to send the pump to one of the professional shops for a good rebuild. After that, I guess that you might turn more like 4800 rpm's at something more like 55-60 mph.
SteveM.

[montrone]

call (Ron) @ AmericanTurbine.com, i have the same set up and he reconmends the "AA" which i have, it's for higher RPM's.....
and the diverter for this pump goes for $600.00....FYI

[Witchcraft]

Thanks for the replys! I am going to get a GPS unit to see what my speed actually is at 5000 RPMs.
Thanks
Mark

[kingb36]

Be sure and check the accuracy of your tach. A lot of the old Medallion & Teleflex tachs are known to be way off. Mine was reading almost 1000 rpm too high. It's important to have both accurate speed & rpm info before you judge the condition of your pump.
HAPPY SQUIRTIN!

[Joker]

Hey witchcraft its not a big deal to check your wear ring/impellor yourself just remove the nozzle and pull the impellor. Have a look at the low pressure side blades and make sure they are smooth and sharp...if not file them down until they are....then check your clearance between the impellor and the wear ring most are @ 25 thou from the factory if yours is over this find out by how much and order the appropriate "over" wear ring. Pop the old wear ring out and install the new one with the proper clearance and you are away. Using a heat gun on the bowl and freezing the new ring works great. Make sure to add a little grease to the inside of the wear ring for initial start up and roosters away....

[Witchcraft]

Made it out last weekend with a GPS unit. 5000 RPM on the S/W tach and it showed 48 MPH. I obviously have a pump problem. Got looking at the pump and it is a Jacuzzi WJ/B. What is this pump? Is it going to be easy to replace the wear ring?
Thanks
Mark

[Bajajet]

Witchcraft,
I don't know anything about Jaccuzzi's but try Jack @ MPD. He has always been willing to help me out. http://home.pacbell.net/jmcclure/
I'm sure you could convince Duane to help you out also!
See you on the river!
Craig