Ski Boat Forum

Repairs and Maintenance => Engine Repair/Maintenance - All Ski Boats => Topic started by: Joel on April 25, 2010, 03:45:02 PM

Title: 40 mph top end??
Post by: Joel on April 25, 2010, 03:45:02 PM

Guys,

My top end is 40 mph or so with two or three people on board...  Is this speed typical for a 1991 Advance with the standard Ford 351 / 250 hp engine with a 4 bbl holley & 13 X 13 LH prop???  I'm sure the carb could use some adjustments, but overall the engine seems to start & run well... 

Title: Re: 40 mph top end??
Post by: Midskier on April 25, 2010, 03:59:01 PM

kind of a loaded question
in real mph I'd say 40 is on the low low side

things that need to be understood

what did you use for a speedo - gps or radar - if not you're only guessing
what is the engine rpm @ WOT - I only trust my digital tach

fuel tank full or empty?
water glass calm or a little choppy?
how many on board 2 or 3
what else is under the dash , boom, skis, wakeboards etc

typical Advance speeds with a decent tune should fall between 43 & 45
my old 18 would see 43.3 - 43. 8
my Chevy powered advances saw 44.2 - 45.8

if your turning a real 4300 - 4500 rpm w/ 13x13 you should be 42-44 mph

Dan T

Title: Re: 40 mph top end??
Post by: Joel on April 26, 2010, 04:29:47 PM

Dan,

I used my two AirGuide speedos - no radar or GPS available.  RPM is approx 4300 with the throttle wide open & new prop/rudder...  original boat tachometer is all I've got.  Full tank.  Little choppy with some wind.  2 persons in the boat.  Only thing under the dash is a fire ext, mushroom anchor, two vests, throw cushion, paddle, etc - enough to keep her legal.

Sooooo to answer my own question... I guess I'm guessing at the speed & RPMs, etc...  I'll see if I can get a water cop to clock me when the water is flat.  That should be close enough and hopefully the SOB wont write me a ticket - they arent much fun up here  :(  Thanks for the feedback!

Title: Re: 40 mph top end??
Post by: chrisheile on April 27, 2010, 06:45:24 AM

Do you know anyone with a hand held GPS.

Title: Re: 40 mph top end??
Post by: Mike Harry on April 27, 2010, 10:01:16 AM

If you know anyone with an iphone or a droid, you can download an app that will give you gps speed. I have it on my phone. Will give you top speed, distance traveled, and avg. speed.

Hope this helps.

Title: Re: 40 mph top end??
Post by: Joel on April 27, 2010, 10:55:18 AM

WOW!  I guess I'll have to take my 14 year old daughter out on the boat... she has an iphone & knows how to use it...  I wouldnt know how to use such gizmos...  I'm just getting good at using the damn internet...  LOL!!!   ::)

Thanks guys.  Anything to keep me from having a face to face with the water nazis is good for me...  Coming from a retired Coastie, thats saying something  ;)

Title: Re: 40 mph top end??
Post by: Mike Harry on April 27, 2010, 11:06:32 AM

Just have her look up "gps speed" or "speed gps" in the apps for her phone, one should pop up that is free. I have the droid so it is a little different or I would tell you exactly how to do it, but same apps should apply.