JBP Blog ,Information, Chat, Opinions & Jet Boat Articles
Regarding oil vs Grease in Berkeley bowls 12/12/09
"Had my berkley 12 jb pump rebuilt and where
you put gear oil in the bowl he put a grease fitting. Is this better
or should i just put oil in it?"
Although somewhat redundant to what been said above ,the true "grease
lube bowls" have little to no "reservoir' as such and they typically
have a grease seal retainer snap ring in front of the shaft/bowl seal.
Some grease lube bowls even have a double snap ring retained seal.
When a true grease lubed bowl is lubed thru the tail shaft plug zerk,
a small amount grease is forced into and around the shaft and
bushings . When a Berk type bowl is "retro grease lubed" the process
depends on pumping enough into the old oil bath cavity to finally fill
the Oil void and hope that the grease will eventually find its way to
the shaft and bushings allowing for air pockets and hoping the front
seal isn't hydraulically "jacked out" in the process . IMO its best to
keep oil in the Berk oil lube bowl to start with and frankly I don't
understand why one would routinely convert from oil to grease as a
matter of course ? :unless for what ever reason the Berk bowl as
"designed" , will for some reason no longer hold oil and one wishes
to make use of it (the bowl despite that existing problem ),this could
result from a multitude of reasons for example if the bowl has
suffered a "spun" tail shaft bushing failure that required line boring
and sleeving, small cracks, casting defects or its a purely "economic"
thing (shaft score in the seal area or etc ...) . That said once a
Berk bowl is filled with grease (which is quite a bit) as yours is and
then reinstalled you might as well leave it. To extricate all the
grease or even the majority of it if lucky is a arduous task requiring
heating warming , thining and diluting the remaining "sticky" (likley
"hi temp") grease to the point of cleaning and draining same from the
bowl oil cavity (not fun) . If this was to be done the time to do it
was when the bowl was stripped down for repairs or overhaul . Heres
the good news , most pump kits and repair parts/replacement bushings
in use are modern coated self lubricating (ptfe) and will pretty much
run and survive in anything grease water oil etc as far as oil
"carrying of heat" the bowl is constantly bathed in and bombarded with
cool water creating a pretty efficiant heat "sink" ;) just my 02 Tom @Jet boat Performance
Join Date: Mar 2008
10/18/09 (answer to a jet boat carburation inquiry)
Don't worry about the carburetors being too big, in a jet boat it won't use what it doesn't need. If your running a pair of 600's i'm gonna guess they're are vacuum secondaries in which case you'll run off the primaries until the engine demands more. and also don't worry about the High RPM's advertized with the TR, it simply means the tunnel ram was designed to make maximum power within that range, Also any torque loss on the bottom end most likley would never be realized in a jet boat unless you are running a large impeller.
A properly tuned pair of caburetors should'nt have much worse fuel economy over a single properly tuned carburetor. I would say they should have the same economy if not for two accelorator pumps pumping in unisinc on a dual set up. Eceptions being the 660cs which have no power valves and are about 8 jet sizes too rich until until you put your foot in it, but these carburetors were designed with WOT in mind, not part throttle cruising .
Typically, when an engine is thought to be over carbureted more often than not the carburetor is impropperly tuned. And most often the lack of economy that follows is due to overly rich idle ciruit, improperly adjusted throttle blades (too far into the transfer slot) or power valve selection. When set up correctly a 600 should flow the same desired ratio of gasoline to air as and 850 with the 850 having a potential to flow significantly more volume if required.
I guess my point/opinion is:
A. More is better, dyno testing(not mine) has shown you can make more power with a bigger carburetor in alot of cases
B. You can achive approximatly the same GPM (Gallon Per Mile) ratio with a smaller carb as you can with a larger PROPPERLY TUNED carburetor/s/engine
C. If i didn't believe what i was saying i wouldn't be installing an 1100+ Dominator on my 408cid engine