If the engine doesn't overheat at idle, I wouldn't worry about seeing water
coming out only one side. You might just have low water volume from the
hose. You should checkout your cooling system while the boat is in the
water. A badly installed water pump kit might not fail until you are running
high RPMs. You may have an engine misfire or worn out exhaust shutters. If
you only hear the noise in reverse, then the noise has to be eminating from
the bullet area in front of the prop beacuse that is where the shifting
takes place. A slapping noise might mean the lower shift cable is defective
or out of adjustment.
JIMinFL
"ToneJohn" wrote in message
...
I have a 94 Chaparral 350MAG w/ an Alpha one. I recently started it up for
the season and encountered the following and need advice / help on possible
cause:
1) When running with earmuffs the water is flushed/spit out only on one
side of the lower unit. If i remember correctly last year it was flushed
out on both sides of the lower unit. I never really paid much attention
but for some reason i remember it coming out on both sides. Any
suggestions on possible causes? I keep my boat dry docked and cover the
lower unit during the winter.
2) With the earmuffs attached and shift into reverse, i heard a constant
"slapping" noise coming for the lower unit area. Doesn't sound like
metal.... But when i give it more juice in reverse it goes away, but then
comes back when i idle slow in reverse.
Things i did before the winter: Flushed and Fogged and backfilled with
Antifreeze.
Things i did in the last few weeks: Changed lower unit lube (old oil lube
was clear). Changed the impeller. Greased Prop Shaft.
I did all of the above with someone who knows what there doing 
Any suggestions are greatly appreciated, before i bring it to the local
marine and get robbed 
THanks !! !
-Matt