How fast should my searay 23' got

horse

Cadet
Joined
Jan 16, 2003
Messages
18
I am considering a purchase of a 1987 23'searay sorento with a 350 and a merc outdrive.<br />I took it out last night with the seller. real nice boat - but i thought it should go faster. it did about 35 if I messed with the trim and got it just right. should it go faster than this? we were at about 6000' (deer creek res in utah)<br />also if anyone has any advice about this boat, engine or outdrive please feel free to share<br />also - it has about 1000 hours on it - is that high or age appropriate?<br />thanks
 

Solittle

Fleet Admiral
Joined
Apr 28, 2002
Messages
7,518
Re: How fast should my searay 23' got

I'll leave the speed question to someone else. On an older I/O ig you need to find out when the manifolds and risers were last replaced. Rule of thumb is when used in salt water they last 4-6 years - in fresh water 5-7 years.
 

horse

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Joined
Jan 16, 2003
Messages
18
Re: How fast should my searay 23' got

What are risers?<br />I do know that the head has been off - milled - new head gasket - <br />are you talking exhaust manifolds or intake?<br />thanks
 

beckerdg

Petty Officer 2nd Class
Joined
Sep 9, 2002
Messages
147
Re: How fast should my searay 23' got

I have a 22.5' seasprite with a 170 mercruiser 4 cylinder. 35 is about the best I can do at sea level with the boat lightly loaded total weight probably about 4000lbs. There might be a few more MPHs to find, but I doubt many.<br /><br />The risers sit on top of the exhaust manifold and is where raw water is mixed with the exhaust to cool it before running it back through the bellows and back out the boat. They are a normal maintenance item and must be changed probably along with your manifolds as they corrode. Failure to do so ends up with a load of water in the engine. Salt water use if you can't flush 3 to 4 years max.
 

Snailman

Petty Officer 2nd Class
Joined
Apr 23, 2003
Messages
126
Re: How fast should my searay 23' got

I've got a 21' Wellcraft (deep V hull) with a 5.7L (350) I/O. She'll do about 30mph (speed over ground) as measure on GPS with 3 adult men aboard. That's about 3200 RPM and trimmed up on plane.
 

horse

Cadet
Joined
Jan 16, 2003
Messages
18
Re: How fast should my searay 23' got

thanks for the responses<br />I will continue to check back
 

jpbaker

Seaman
Joined
Aug 18, 2003
Messages
63
Re: How fast should my searay 23' got

horse, I had a 86 Four Winns Cutty, 21.5 foot w/305 230hp 4barrel best I could do is about 35<br />on a good day, (Denver metro area) You didn't say<br />if you had a cutty or open bow. Remember, 23' is alot of fiberglass to push through the water. If you want to start somewhere make sure the distributor is clean and not cracked and the rotor looks good. Then check your timing, this is where I picked up most of my top end (the boat came from Michigan). Check plugs, ect. If all this<br />checks out. Check to see if you're getting max (or<br />close to max)RPM at wide open throttle. All this can be done quite simply without spending a dime.<br />Also remember higher in altitude the slower it will run (less air getting to carb). Happy Boating :D :) :D :) .
 

horse

Cadet
Joined
Jan 16, 2003
Messages
18
Re: How fast should my searay 23' got

Hello again<br />I went yesterday to do a compression check on this motor - I pulled the plugs one at at time. when I got to the plug on Cyl #8 I pulled it and water came out of the plug hole.........<br />so - I am assuming it has a cracked block or head or a blown head gasket - I offered him 4k less than he was asking to compensate for the price of an engine replacement - I am waiting for a response.<br />If he takes the deal I will either put a new GM engine or a rebuilt engine and new heads in it.<br />we will see
 

ndemge

Commander
Joined
Jul 15, 2002
Messages
2,644
Re: How fast should my searay 23' got

Bummer on the water.... if it still did 35mph with THAT kind of engine.... rebuild that engine and you'd probably get good speed!
 

horse

Cadet
Joined
Jan 16, 2003
Messages
18
Re: How fast should my searay 23' got

If he will take an offer I will still get the boat<br />it is a nice boat just was not winterized properly or overheated.
 

MrBill

Senior Chief Petty Officer
Joined
Aug 4, 2002
Messages
710
Re: How fast should my searay 23' got

horse:<br /><br />You should be able to get the outdrive gear ratio and prop pitch to determine theoretical speed at WOT rpm. Figure 15% slip (maybe more with that set-up)and you'll have your answer. If you send me the stats I'll give a quick estimate.
 
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