28 zx intro and two questions
#1
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Hey all,
Year long stalker, first time poster. I bought a 1999 zx28 last fall with twin 350's and I am just shutting it down after our first year up here in 'sconsin. The boat is a bit of a bitsa... 250hr reman long blocks, non original lowers, and needed love. It is now running and looking MUCH better than it was and the last run this summer was about 63 gps at 4950 on 1.5's with stock 23p mirage+'s, trims at 50% or higher. Less than perfect water on lake MI. Anyways...I am hoping to glean some info from those that know more than myself.
First question - are the bravo 1 lowers on the zx's supposed to be low water pickup style? I have one that is and one that isn't. Both are quiet and don't use oil. The low water pickup side runs a touch warmer (not enough to make me worry) and I have yet to investigate if it is thermostat ( tstat and pump/housing new this year) or gage related. Winter is coming and I could swap a housing to make them the same...just cuz.
Next one - I still have the original trim gages and while I definitely see the advantage of the manual indicators, it's what I have and they are currently working well. That said, this one is for anybody else that still runs these gages. 0% sure seems to be correct, but my limit switches are currently set to stop travel at 75% on the gage. I would need to use the trailer switch to actually make the needle reach 100%. Is this correct? At WOT and 75% there is no real rooster tail if that is any seat of the pants indication of drive position. Just looking for ideal drive position for top speed. %50 to 75% didn't seem to change much gps wise on the water I had.
That's about it for now Thanks for any and all input.
Ryan
Year long stalker, first time poster. I bought a 1999 zx28 last fall with twin 350's and I am just shutting it down after our first year up here in 'sconsin. The boat is a bit of a bitsa... 250hr reman long blocks, non original lowers, and needed love. It is now running and looking MUCH better than it was and the last run this summer was about 63 gps at 4950 on 1.5's with stock 23p mirage+'s, trims at 50% or higher. Less than perfect water on lake MI. Anyways...I am hoping to glean some info from those that know more than myself.
First question - are the bravo 1 lowers on the zx's supposed to be low water pickup style? I have one that is and one that isn't. Both are quiet and don't use oil. The low water pickup side runs a touch warmer (not enough to make me worry) and I have yet to investigate if it is thermostat ( tstat and pump/housing new this year) or gage related. Winter is coming and I could swap a housing to make them the same...just cuz.
Next one - I still have the original trim gages and while I definitely see the advantage of the manual indicators, it's what I have and they are currently working well. That said, this one is for anybody else that still runs these gages. 0% sure seems to be correct, but my limit switches are currently set to stop travel at 75% on the gage. I would need to use the trailer switch to actually make the needle reach 100%. Is this correct? At WOT and 75% there is no real rooster tail if that is any seat of the pants indication of drive position. Just looking for ideal drive position for top speed. %50 to 75% didn't seem to change much gps wise on the water I had.
That's about it for now Thanks for any and all input.
Ryan
#4
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You can drill the lowers to make them match if you want,, trimming you really have to watch speed vs rpms, trim too high you will gain rpms and lose speed. I use mechanical indicator mostly for knowing where level is.. prop shaft to hull bottom, I correct trim all the time with changing water and direction, that is a very busy button in my boat. unless I'm just cruising.
if you keep the trim gauges you have make all the way in zero, trim up to level and see what the gauge reads. work from there
if you keep the trim gauges you have make all the way in zero, trim up to level and see what the gauge reads. work from there
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Interesting, I didn't know the nose of the non-low water pickup could be drilled. I'll chase that one and see what I can learn.
I will be adding the trim switch to my throttle this winter. They are currently dash mounted and I find I like to use them too much for that to be convenient. Down is definitely zero, I am confident on that one. Guess my only issue with the trim is lifting them too high while chasing mph. Is it possible to trim high enough to reduce water intake without aerating the props, or is the only detriment to trimmed 'too high' less speed and/or rev limit? Next year will have some lab work and full hyd steering and i'll chase the mph numbers with respect to trim some more.
Thanks again for the input.
I will be adding the trim switch to my throttle this winter. They are currently dash mounted and I find I like to use them too much for that to be convenient. Down is definitely zero, I am confident on that one. Guess my only issue with the trim is lifting them too high while chasing mph. Is it possible to trim high enough to reduce water intake without aerating the props, or is the only detriment to trimmed 'too high' less speed and/or rev limit? Next year will have some lab work and full hyd steering and i'll chase the mph numbers with respect to trim some more.
Thanks again for the input.
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The old ones didn't have low water pickups. It started very late in the run, something like 2006. My 2008 has them but it is one of the few that has them and the 3rd to last 28 to leave the factory
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thanks Vette. I have read through all your 28zx propping posts numerous times and will be talking to Brett or DAH at some point this winter. I may be cruising right past brett soon while helping a friend purchase a PWC. I have the stock 23p M+ and at 4950/5k rpm and a last recorded gps of 63.9 the boat seems to be pretty typical, even on a little bit wavy day. Sounds like the older boats like the 3 blade and the M+ where the newer 28zx's like the standard M or the rev 4 blade. I need to ask brett if it is easier to get more speed from the 23p or bump to a 25P and try and get the rpm back up. Either way approaching 70 would be pretty sweet. So far I have zero complaints about the 23pM+. I don't vent/cav on accel but I really don't ever really try and 'hop' up on plane either.
do your low waters have four holes right in the very front of the nose cone or are they more underneath? I'm not sure but mine may even be an aftermarket lower. As mentioned, our zx was a bit of bitsa. She's older, buts seems to be pretty sound and is getting some much needed attention. I lust after the sweet white/blue 04 that's for sale in iowa but ours was less than half what they are asking!
do your low waters have four holes right in the very front of the nose cone or are they more underneath? I'm not sure but mine may even be an aftermarket lower. As mentioned, our zx was a bit of bitsa. She's older, buts seems to be pretty sound and is getting some much needed attention. I lust after the sweet white/blue 04 that's for sale in iowa but ours was less than half what they are asking!
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Good to know about the 23's. Did you have your done, what did you see as a result?