[wonsnam]

I finished changing the block on my used Z201. I reused all original parts from motor that was cracked . Renewed bearings and what not. I water tested it last Saturday and got a few hours on the new rebuilt motor. We took it to Lake Winnipesaukee where we have a camp for a shake down run, and I want to tell you this thing flies. It runs along at 40 MPH very nicely @ about 4000RPM when I hit the throttle to full it jumps right up and goes to 5200 RPM and 55 MPH on the speedo. Sets you back in the seat, even hitting it @ 40. I am very Happy with the performance but I'm going to have to watch out for the MP in the future as they are trying a speed limit on the Lake of 45 MPH, Damn Drunks a couple of fatals at night involving speed and alcohol and everyone pays. Oh well that's not in affect till Jan. 09 so at least I can have some fun the rest of this season.

[WetWilly]

Hi wonsnam,

Glad to hear your 4.3 is running great and your Mariah is back in the water!

I would watch the RPMs as you're over reving it at 5200 RPM. Book states your max should be between 4400 - 4800 RPM. Looks like you may have a shallower pitch prop than stock.

WetWilly

[wonsnam]

I checked the prop and it is a merc 14.25 21p which is what I believe is the correct one for the applications, or it is according to merc's prop chart. I thought of the over rev and will check the boat tach against a digital tach. Another thing is that I can only trim out half way on the trim gauge before it starts to cavitate, which is strange, bow down @ 55 is scary. going back up this Friday (tomorrow) to play. Will fine out hopefully what's up.

[indykoch]

Yeah, my thought would be the tach is slightly off. A 4.3 pushing a 21p prop on a 20' boat sounds like a near perfect set up. I doubt it could really be turning 5200 RPM's with that set-up, but I could easily be wrong. Most 4.3's I know of are turning 19p props with great hole shot and just touching the rev limiter, so 21p should be keeping it down.

Now the real question... what are you doing WOT on a newly rebuilt motor?!?! I'm hoping you "broke it in" a little bit at least. Although, I've also heard "break it in like you intend to drive it", but I don't totally agree with that.

Glad to hear you have the boat up and running again... congrats!

[wonsnam]

I broke her in for a couple hours the first day in the water, yesterday took it easy, up and down the power range for the first couple of hours and only gave it short blasts at full throttle. I am an old time master mechanic been twisting wrenches for a living since the 60's I raced small blocks and big block for years, if it is going to break better now before winter than next season. I boat for relaxation so I rather find out this year then next if I have a problem. Besides all the internal engine parts were all ready stress relieved from previous use I basically renewed bearings bushings rings, and gaskets. If I messed up on assembly would be the only concern. We did do a three angle valve job while it was out which will help it breath better but i dought give me 400 rpms. Will let you know after the week-end, can't believe it is Columbus Day already.
Brynn

[indykoch]

Originally Posted by wonsnam

I am an old time master mechanic been twisting wrenches for a living since the 60's I raced small blocks and big block for years...

Yes, you definitely qualify as someone that knows what they're doing!!! I didn't mean to second guess about breaking it in, just my feable attempt to be humorous.

Good luck with everything... keep us posted on what you find.

[wonsnam]

Ryan
Not a problem, I didn't take it that way. With all the hard parts already broken in I usually run them long enough to check for leaks and thermostat operation, oil pressure, and water flow. Like you said break'em in the way you run them has been my motto. Most of the diesels I overhaul go right back to work so I take extra care when assembling engines, cleanliness, quality parts and attention to specs & tighten sequences have payed off for me.
I like the way this Z201 gets up and goes from no wake speed and top end is only an occasional urge, most of my cruising is in the 25 30 MPH range as I am in no hurry to get any where out on the Lake. I am thinking of taking her to FL this winter to use on the intercostal and run to the keys. I am going down the end of the month to check out a couple of boats already there but if I don't purchase one of them the Mariah will winter in Fl.