Z25 Questions

[Andy McCarty]

Hello guys.. Hope everyone had a wonderful weekend. I have a few questions concerning my (new to me) 88Z25. This weekend is the first weekend i was able to run it some. 1st of all what RPM should i run the motor @ (454 330hp) 19pitch ss quicksilver prop? 2nd How fast should the boat run. 3rd boat takes on a little water. Once i take the boat out of water i have enough water in it to kick the auto bilge pump on when driving down a hill. Is this normal water intake. this amount of water was after about 4 hours our so on the water. Any help would be very appreciated.:wavey:

[GKricheldorf]

Hi Andy,

My 87 is rated at 4600-4800 RPM WOT, but that was before i blew the motor. I just dropped in my new motor this weekend and it is pretty much the same - 4800 RPM.

Last season i was running 56 MPH on the GPS. I know i didn't have the correct prop, but didn't really care. It was my first boat and i was happier then pigs in $hit anyway. Now with the new motor i am going to get it propped correctly. I have two props to try out. One is a 21 degree 3 blade and another 23 degree 4 blade.

On a busy day in and out of the water i never got that much water in the bilge with 5 people in the boat. It would be about an inch below the bilge pump. But you did say going down hill it kicked on the pump. How about before you pulled the boat out on the water?

[Andy McCarty]

Bilge never kicked on out on the water. let me know how your test goes witht he props. i think i am way underproped. What happen with your motor and how many hours were on it befoer it blew. :rolleyes:

[GKricheldorf]

There are 316 hrs on boat. The motor was the original according to the serial numbers. It may have been lack of experience or maybe just time to go. One thing I would always do the morning before we went out for the day was start up the boat and make sure everything was ok. I’d put the ear muffs on the out drive and turn on the water. Most of the time I would jump in the boat and start it right up, but other times I wouldn't get in the boat for 5 minutes and just let the water run. I may have forced water into the motor. My water pressure is really high. Or since I didn't have the flaps on the thru hull exhaust I may have also sucked water back into the motor.

Fish Boy posted some links to calculate you prop pitch in the Surf and Turf thread. You'll need to know your drive ratio and I think you could assume 4800 RPM WOT on your motor. I've got to break in the motor before I can open it up, but I can't wait.

[wytmike]

Andy,

You'll find with the Z25 that you do get quite a bit of water in the bilge from normal use. The way the stern is designed with the low height and the ventis in the back that coming off plane the wake will surge up and onto the sun pad if you come off plane quickly. The vent on the rear of the boat and the sun pad drains directly into the bilge. It usually takes 3-4 times coming off plane to trigger the automatic bilge. If you are going to leave it on a bouy for extended periods of time get a cover that covers all those vents. Ours sank in a wind storm from waves washing into the stern vents. I also know of 2 others at Lake Tahoe that have done the same. Great looking boat marginal design.

Mike

[Andy McCarty]

I dont have the flappers on the exhaust. do you all think i need them. or am i ok. This is my first big boat and i dont want to do anything stupid and blow this thing up.. I have a buddy that has a 23 pitch 3 blade prop im going to try this weekend. any input that will save the life of my boat please let me know. i plan on keeping this thing for a while. i love the lines and the boat contiuously go plenty of looks on sunday and monday. and as most of you that went to aoth you all know htere are some nice boats here in KY at lake cumberland.
:D

[Donzigo]

Get the flappers, for sure.

You shouldn't be much water in the bilge. Somethings causing it.

[Speed-Racer]

Water in the bilge, could be because at the facory someone could have missed drilling a drian hole somewhere...On our 16' we had the same problem.When out on the water, it must have bounced around enough to collect in the bilge when pulling out. So we took it upon our seleves to pinpoint the location of the misssing hole, and drilled one -problem solved-

Just another idea...

[zzrhino]

andy i had similar water problem i checked all seals around drive and every thing in the transom area found leak to be in throttle line entry sealed it and it maid my day!! Andy always when i come off plane i watch the back surge just before it gets to stern i give it a little gas to miss it, give it a try.as far as prop i to brought this question up to the z25 veteren (donzigo) we talked a great deal on this and the prop he pushed just happens to be the one in my boat..i get great performance with a mirage plus 23P that seems to work well in the z25 . after speaking with the turbo guys at the AOTH i explained to them i do go off shore,My second prop will be a 4 blade same pitch they said the 23 3blade good choice for lake.again andy these are things i did with my z25 and my tastes, yours might be differnt but if it can help in any way give it a shot. glad to see you got it out. ZZRHINO :boat: :yippie:

[Andy McCarty]

Thanks guys for all your input. ZZ i have a mirage 23p to try next weekend that a buddy of mine has. I will let you know how it turns out. The water issure i really beleive is from when i come off plane i do throttle it a little but still getting water. next time o go out i am going to check it really well. Try to find out where it is coming from. ZZ what kind of speed are you getting with the 454 fuel injection. and what kind of speed where you getting out of it before you changed the motor. Thanks Donzingo. I hear you might be the Z25 expert. I will probably be picking your brain as the years pass. Thanks again everyone for the info. It is amazing how much and how nice all of you are. I also post on a duckhunting forum and not near as helpful. Must have something to do with the company we keep and passion for our boats.:biggrin.:

[jdsdls]

You need the flappers in the exhaust when you come off plane it stops the water from rushing back up. Trust me I lost a moter on my z-22 because I did not have flappers.

[Andy McCarty]

Does any one know if the exact size of the stock exhaust. i think they are 4". i would like to get the flappers before i go back down in 2 weeks.

[GKricheldorf]

They are 4 inch - i got mine from these guys. I didn't spend to much time price shopping. I was ordering parts from this company at the time. I almsot ordered the stainless tips with the flappers, but had to curb my spening :O

http://www.diversified-marine.com/Exhaust.html