Problem With No Power

[76sleek]

I have a 76 sleekcraft with a 454 mercuriser and a berkley jet. When in gear at low rpms the boat is fine but if i throttle up I get very little jet propulsion and the boat shakes badly. The motor runs fine. please help.

[Squirtin Thunder]

I have a 76 sleekcraft with a 454 mercuriser and a berkley jet. When in gear at low rpms the boat is fine but if i throttle up I get very little jet propulsion and the boat shakes badly. The motor runs fine. please help.
Something in or near the impeller. It could be a damaged impeller.

[IMPATIENT 1]

I have a 76 sleekcraft with a 454 mercuriser and a berkley jet. When in gear at low rpms the boat is fine but if i throttle up I get very little jet propulsion and the boat shakes badly. The motor runs fine. please help.
THIS IS WHAT IT FELLS LIKE WHEN YA SUCK UP A ROCK!

[76sleek]

Thanks for the help, I have checked the impeller and it looks fine and no rocks, I was in deep water at a high rpm when the problem started. any ideas?

[sleekcrafter]

A tiny bark chip, something like mulch will cause that too. you should take a look in the clean out, with the engine "OFF" and form under neath the boat up thru the intake. It's should not be too hard to find, your problem. If you don't find any thing, it may have came out when you pull your boat on the trailer.
Sleek

[Squirtin Thunder]

Rocks and shit in the bowl.

[Oldsquirt]

Sleek it's possible that something passed through the impeller and is now between the impeller and the bowl vanes. Earlier this year someone had a rock get most of the way through the impeller(you cant see that far by looking in the front). Had symptoms like yours and ultimately found after removing the bowl. It is also possible that you had suck something up against the intake grate that has since fallen off. It takes as little as an empty ice bag on the impeller shaft(happened to me this summer) or blocking the grate to disrupt the water flow enough to cause what you experienced.

[76sleek]

I hate to sound stupid but i just bought this boat and it is my first jet. Used to props ya know. What is the clean out?

[76sleek]

Wow lots of new stuff for me to learn. Again I am stupid. What is the bowl vane? Looks like a long road ahead in learning a new system.

[Squirtin Thunder]

It is all fun stuff !!! :cool:

[sleekcrafter]

This might help you under stand a little better.
Sleek
http://americanturbine.com/images/diagrams/jets/OEM_berk12jg_diagram.gif
SYM.
DESCRIPTION
QTY.
PART NO. SYM.
DESCRIPTION
QTY.
PART NO.
1
Aluminum Impeller 1
IMB**A 29
Bearing Cap Clipper Seal 1
SL1007
2
Bowl 1
SC9102 30
Bowl Clipper Seal 1
SL2003
3
Suction Piece 1
H-1727 31
Nyliner Bearing 4
B2007
4
Hand Hole Cover 1
M-4128 32
Ball (Thrust) Bearing 1
B1007
5
Nozzle Housing 1
R1007 33
Retaining Ring, Bearing 1
SH1507
6
Steerable Nozzle 1
L-4501 34
Impeller Nut 1
SH3507
7
Split Gland, Packing 1
SC2507 35
Groove Pin, Hand Hole Cover 2
S-14479
8
Bearing Cap 1
SC2007 36
Grease Fitting, Bearing 1
S-14480
9
Reverse Bucket 1
L-4251 37
Impeller Key 1
SH3007
10
Pump Shaft 1
SH1107 38
Woodruff Key, Tiller Shaft 2
R5507
11
Bowl Bearing End Cap 1
SCA9001 39
Locknut (3/8" - 24) 1
S-26431
12
Sleeve, Shaft Seal 1
SH2507 40
Packing Gland Bolt (3/8 x 2 HHCS) 2
F06 24 16 HH
13
Impeller Wear Ring 1
WR5000 41
Packing Gland Nut (3/8) 2
F06 24 TL
14
Wear Ring Insulator 1
WR6004 42
5/16 LockWasher 11
F05 LW
15
Tiller Shaft 1
S-15396 43
Bowl To Suction (1/2 x 1-1/4 HHCS) 8
F08 13 10 HH
16
Reverse Bucket Shaft 2
BN2510 46
Nozzle & Bucket (5/16 x 1 SHCS) 3
F05 18 08 SH
17
Bowl to Nozzle Gasket 1
G2507 47
Set Screw, Tiller Shaft (5/16 x 3/4) 1
S-23665
18
Bowtl to Suction Gasket 1
G2006 48
Barbed Connector 1
S-14821
19
Bearing Cap Gasket 1
G1502 49
Flange Nut, Hand Hole Cover (5/16) 2
S-23680
20
O-Ring Nozzle 1
O1502 50
Fastener, Lock Wrench 1
S-14493
22
Wrench, Hand Hole Cover 1
S-11543 51
Fastener Screw 2
S-25599
23
Rod End, Hand Hole Cover 2
S-10907 52
Pipe Plug, Oil Reservoir 2
SC9902
24
Set (5) Packing Rings 5
SC3007 53
Bearing Cap (5/16 x 1-1/4 SHCS) 4
F05 18 10 SH
25
O-Ring, Hand Hole Cover 1
O1002 54
Plastic Rudder Kit B-07486
26
Suction Piece Clipper Seal 1
SL1507 55
5/16 - 18 x 1 HHCS 7
F05 18 08 HH
27
Bowl To Nozzle (5/16 x 3/4) 1
F05 18 06 HH 56
5/16 - 18 x 7/8 HHCS 1
F05 18 07 HH
28
Bowl Bearing (Glacier) 2
B1502

[76sleek]

thanks for the diagram, that will really help, also my 76 is 23 feet, is it normal to have to run 4500rpm to keep the boat at a decent speed and on plain?

[sleekcrafter]

thanks for the diagram, that will really help, also my 76 is 23 feet, is it normal to have to run 4500rpm to keep the boat at a decent speed and on plain?
76SLEEK, I had a 77 Executive, 12JG I could plane off with 3500rpm's
You may have a worn pump, might be worth pulling off the bowl to have a look. This was my beast, the picture's are after the AmreicanTurbine pump was installed. The best impeller for this boat was an AAA Legend impeller when I ran the Berkeley pump. The Turbine pump I ran the AA impeller.
Sleek
http://www.hotboatpics.com/pics/data/500/7363000_0032.JPG
http://www.hotboatpics.com/pics/data/500/7363000_0026-med.JPG

[SmokinLowriderSS]

You either have something trapped in the impeller/intake/bowl vanes, or you DID and it came out. As said here, anything that disrupts water flow (from diapers to bent lips on the impeller) will cause cavitation as RPM climbs. There is a cleanout hole with 2 fasteners somewhere on the suction piece of the pump. If it is outside the hull as on a Berk E or F pump, you can open it whenever you want (NOT with the motor running!!!). If it is inside the engine bay, DON'T OPEN IT FLOATING, or you will not float long, on the trailer only.
The "Bowl" is the rounded bowl-looking part behind the boat and ahead of the nozzle assembly. Inside it is a set of vanes that "catch" the water swirling off the impeller and guide it (straightening the flow) to the nozzle. You will see them if you ever take the bowl off.
A higher than "normal" RPM can easily be caused by a worn pump to wear ring clearance (sand is hell on them as is picking up road grit while trailering then starting it). It can also be caused by a smaller impeller.
Some "typical" info, your setup may vary, as will what you want.
Smaller cut impeller gives the same push at a slightly elevated RPM than a larger impeller. The sizes are alphabetical from at least AAA to D (AAA,AA,A,B,C,D) with A being very comon for most cases. This size and RPM is used to fine-tune the drive to your hull and engine. Typically, to a given engine setup, a larger impeller will push harder which helps acceleration, pulling, and for larger boats, but it reduces your RMP so you may not be able to get to your engines greatest power, or best speed. A smaller impeller will allow the engine to wind up more, thus make more HP (unless going past the engine's peak) and help top-end speed but at the cost of some acceleration and ski/tube pulling ability, as well as mileage (due to higher RPM's. Impeller flow does vary some by design from different manufacturers. For example, it is prerry accurate I guess that an Agressor impeller flows the same as a Berkeley (the comparison standard) of 1 size larger (ie, an Ag "B" will flow similar to a Berk "A", an AG "A same as Berk "AA", etc).
Hope this was helpful, I love my jet.

[Ken F]

I even sucked up a 1/2" diameter twig about 2" long which got caught toward the center of the impeller in the vanes. Did the same thing you describe. A small 1/2-3/4" rock can do the same. It's amazing that just such a tiny disruption in the water flow can cause such problems.
Ken F