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motomutt
05-31-2006, 01:23 AM
I've got a '90 Prostar 190 with about 700 hours total. Great compression, 36 degrees toal advance, secondaries are operating o.k., throttle plates open all the way, premium fuel. No difference between about 3/4 throttle and full open. I just rebuilt the carb (vacuum leak) to no avail. I'm not sure of the accuracy of the stock pitot tubees for the speedo but it seems like I should be getting about 8 - 10 more mph out of this. Motor and tranny seem "sound". Is this all this boat is supposed to muster ? I use it a lot more for recreation than skiing (shoulder injury). Any and all feendback helps. Thanks :confused:

88 PS190
05-31-2006, 01:28 AM
Do the throttle plates open all the way by use of the throttle? Or by opening them by hand?

If you have access to a course or other means to check your speedos do so, I get around 45 out of an '88 and would expect similar.

erkoehler
05-31-2006, 01:29 AM
What prop are you running?

PendO
05-31-2006, 01:53 AM
I've got a '90 Prostar 190 with about 700 hours total. Great compression, 36 degrees toal advance, secondaries are operating o.k., throttle plates open all the way, premium fuel. No difference between about 3/4 throttle and full open. I just rebuilt the carb (vacuum leak) to no avail. I'm not sure of the accuracy of the stock pitot tubees for the speedo but it seems like I should be getting about 8 - 10 more mph out of this. Motor and tranny seem "sound". Is this all this boat is supposed to muster ? I use it a lot more for recreation than skiing (shoulder injury). Any and all feendback helps. Thanks :confused:

RPM's at Wide Open Throttle (WOT) ??

motomutt
05-31-2006, 09:40 AM
The primary throttle plates open completely by lever. I'ts hard to tell about the secondaries as it gets kinda sketchy while under WOT looking down the carb. I know the vacuum to the secondaries is ok. I'm not sure what prop is onthe boat. It came with it but I understand that that should only account for a few mph anyhow. What kind of speed should I be getting on top end ? How accurate are the stock pickups at the rear for gauging speed ?

Leroy
05-31-2006, 09:50 AM
Check speed with GPS or other certified source. Also what Pendo said, how many RPM's at WOT?


Stock pickups can be way off or very accurate, but need to be calibrated and if they haven't been calibrated recently I would guess they are off.

Kevin 89MC
05-31-2006, 11:55 AM
I get about 43.X mph for my top speed. If completely empty of gear & passengers, I can hit 44. Even loaded down, though, I can always get over 42. This is according to Perfect Pass paddlewheel. I'm also curious about your RPM's. IIRC mine is about 4300 rpm at WOT (forgot to look today). I broke one pitot pickup a few years ago, and replaced it with a different manufacturer. The speedos never did seem to match after that. If I calibrated them at one speed, they'd be off at other speeds. Fixed that by installing PP! Kept the speedo with the new pickup, and it matches PP pretty closely. Your old pitot tubes may be shot.
I also get no increase beyond ~3/4 throttle (from when the throttle lever is level with the armrest, to completely buried). That was the same on another '89 PS 190 I used to drive.

rodltg2
05-31-2006, 12:04 PM
when i read this thread title, i thought someone was trying to suggest a top speed of 38 for skiing the course. now that would be interesting!

#47of100TeamMC
05-31-2006, 12:24 PM
when i read this thread title, i thought someone was trying to suggest a top speed of 38 for skiing the course. now that would be interesting!

Same with me... That's why I clicked on it so fast! Got my wheels turning too... cuz this weekend, Flying across the lake at 50+mph I'm thinkin'... geez the wake is NON-Existent at this speed. hmmm, Then I thought back to the cartwheel I did over the wakes from 5ball to 6 at 32mph about 15minutes before that and decided, No, I think the speeds are just fine the way they are.:D

PendO
05-31-2006, 12:37 PM
The primary throttle plates open completely by lever. I'ts hard to tell about the secondaries as it gets kinda sketchy while under WOT looking down the carb. I know the vacuum to the secondaries is ok. I'm not sure what prop is onthe boat. It came with it but I understand that that should only account for a few mph anyhow. What kind of speed should I be getting on top end ? How accurate are the stock pickups at the rear for gauging speed ?

If I was only hitting 38mph, I would graph my mph agains rpm's, and also look at the prop size to make sure it is stock and not nicked at all ... but as someone suggested, gps is likely the best way to know true speed, I would just want to know rpms and then look at the prop and the the throttle cable.

rodltg2
05-31-2006, 12:41 PM
pitot stlye speedos are very inaccaurate unless you calibrate and clean them often. i think thats your problem. if you dcant get or want to buy a GPS , try and find a slalom course. take a stop watch and calibrate those speedos..

threadjack, penod you get the owners manual ?

lakes Rick
05-31-2006, 03:39 PM
I agree with Pendo, check your prop over REAL well.. Just veryslight bend or ding can shave off 5mph pretty easy.....

motomutt
05-31-2006, 07:34 PM
In my dreams brother. Motomutt

motomutt
05-31-2006, 07:39 PM
I meant to reply to the thread that was assuming my fat old butt could slolom at 38 mph. Only in my dreams. I'm still getting over an injury from ski season. Thanks for all the input. Approx. 4300 RPMs and it runs like a champ. I'll check the prop, get some new pitot tubes and calibrate. Y'all Rock. Motomutt

PendO
05-31-2006, 07:46 PM
from the 1990 owners manual it looks like 4600rpm was the max ... so you are close, if you need a copy http://www.mastercraft.com/manuals/1989-1990_OwnersManual-PS190.pdf ... (Page 14 of owners manual) if you are getting to 4300rpm's then 38mph does seem very slow (once spedos are calibrated), also what Altitude are you at?

ted shred
05-31-2006, 08:52 PM
pitot stlye speedos are very inaccaurate unless you calibrate and clean them often. i think thats your problem. if you dcant get or want to buy a GPS , try and find a slalom course. take a stop watch and calibrate those speedos..

threadjack, penod you get the owners manual ?

What he said. The only way to really tell is get out the stopwatch. Also if you have a powerslot it will have a little less top end than a 1:1. My PS tops out about 44mph.

Kevin 89MC
06-05-2006, 12:32 AM
I just edited my prev post, I also top out between 43 & 44.

h2oowl
06-16-2006, 03:33 AM
I have a 89 tristar 190 same set up and I run neck and neck with friends in their pro 190. You should get 43 to 46 MPH at up to 44-4500 rpm. Good rule of thumb is 2400 rpm equal 24mph 3500 equals 35mph and so on. All with a 13x13 or 13x 12.5 prop. Engine timing is very critical. You should hear your secondaries kick in at about 3300 rpm there will be a distinct change in air intake sound. A gps is a good tool for a day on the lake. My pitots are always plugging up. Check and replace your fuel filter regularly at least once a season. Especially with todays ethenol based fuel.

east tx skier
06-16-2006, 12:36 PM
And make sure your flame arrestor gets cleaned regularly. I recommend the GPS for checking speed. Although the general rule of RPMs/100 = Speed will get you close in a pinch. In my application, My speeds are usually approximatley about 2 mph faster than rpm/100 until you get up into the WOT RPM range where they are within about .5 mph.