Author Topic: GT-150 speed stats (Read 57286 times)

Hyperacme · « **Reply #100 on:** August 31, 2014, 07:47:49 AM »

OK Joe ...
Time to flip your hull, grind and build up a pad, take out the hook, if you have one, then sharpen up the stakes.
Get a electric jack plate and hydraulic steering, then you'll need that 1975 135 HP Evenrude for $895 on the local CL.
Start combing eBay for Second Effort speed parts, send a few props out to be labed .
Remove wind shield and go on a diet ...
You should be able to break 55 mph with easies ...

LOL ...

On a serous side ...
That 135 Rude would look SWEET on the back of your GT !

http://minneapolis.craigslist.org/ank/boa/4594327762.html

thedeuceman · « **Reply #101 on:** August 31, 2014, 09:40:27 AM »

Well...
In all reality most of what you listed is my plan for the GT-160

Retro Performance · « **Reply #102 on:** August 31, 2014, 12:39:06 PM »

That Silver Starflite is cool....I remember when they came out. I think they were only out for 1974 and 1975?

V153 · « **Reply #103 on:** August 31, 2014, 01:37:56 PM »

Silver Starflite's are cool, but my favorite's the Super Strangler. Two carbs for each cylinder. WooHoo! (Not known for their fuel economy ...)

V153 · « **Reply #104 on:** August 31, 2014, 01:48:53 PM »

Quote from: thedeuceman on August 30, 2014, 06:37:34 PM

Doug, I think it does have high compression heads, when I first got it I noticed the spark plug gaps were closed when I ran standard plugs, so I have to run serf ace gap Plugs.

I member you saying that Joe. But I don't think that motor came with hi comp heads. Squish oughta be about the same either way. Mebbe somebody sawed on the ones that are on it? Who knows. Only one way to find out.

edit. Yo Joe. Can you find a part # on the head(s)?

thedeuceman · « **Reply #105 on:** August 31, 2014, 06:11:00 PM »

I kno the wernt spose to have them, just figured it may be the case cuz the 135's call for serface gap plugs only. I do kno this motor has not been apart. I also have 2 135 parts motors and another 115 with good comp so should be able cobble something together.
Think what this guy did with the kona looks like a good place to start with the 160
http://forum.cgoamn.com/index.php?topic=3783.msg45144#msg45144

Plugcheck · « **Reply #106 on:** August 31, 2014, 07:45:12 PM »

Pushing 50 in a GT is quite impressive, and I admire your courage, the time you spend, and the tenacity you display chasing down that goal. My CVX16SS had a top speed around 45 at 4800 RPM, but it got a bit squirrely at that speed, handling changed dramatically. It sounds like your close.

Retro Performance · « **Reply #107 on:** September 01, 2014, 10:00:59 AM »

Quote from: thedeuceman on August 31, 2014, 06:11:00 PM

I kno the wernt spose to have them, just figured it may be the case cuz the 135's call for serface gap plugs only. I do kno this motor has not been apart. I also have 2 135 parts motors and another 115 with good comp so should be able cobble something together.
Think what this guy did with the kona looks like a good place to start with the 160
http://forum.cgoamn.com/index.php?topic=3783.msg45144#msg45144

That is the good old days....aired up with no pad and single cable steering....mid 60's on an 800 pound hull seems good

higgins · « **Reply #108 on:** November 17, 2014, 12:16:31 PM »

Hey guys,

I rebuilt both a '79 GT-150 and a '84 Merc 115 and finally got it on the water two weeks ago. The boat started chine walking at 50 mph and we were able to get it up to 56 and there was still room left on the throttle.

I have a 2 blade bronze prop with a 23 inch pitch.

My plans are to extend the two incomplete strakes put a pad on it. I'm open to any suggestions as to how to install the pad.

Hyperacme · « **Reply #109 on:** November 17, 2014, 11:29:12 PM »

" I'm open to any suggestions as to how to install the pad. "

Might be easier to just get a CVX16 ....

56 MPH is pretty darn good out of a GT150 !

thedeuceman · « **Reply #110 on:** November 18, 2014, 09:02:22 AM »

i did some looking around last year and this is the only thread i could find relating to adding a pad to a GT.
http://www.screamandfly.com/showthread.php?251915-glastron-gt150&highlight=glastron+gt150
i think Greg is right, be easier to get a CVX.
my original plan was to add a pad to my GT160 when i redo it, was gonna just copy the pad like a CVX16 has. but after talking to Don and reading the article he posted i think that would yield similar results.
here are 3 links relating controlling chine walk
http://www.boatdesign.net/forums/stability/chine-walking-17405.html
http://www.hydrostream.org/TechTalk/ChinewalkTheory.htm
http://www.screamandfly.com/showthread.php?178921-strakes-vs-pads-rocker-vs-hook
unfortunately i will not be getting into my GT150 for a while (need to put my open bow IO on the water next summer).

Hyperacme · « **Reply #111 on:** November 18, 2014, 09:28:14 AM »

I have read articles on how boat company's (Hydrostream in this case) tune hull designs.
First come up with a design that should work, test ... Bring back to shop and add or subtract material to hull ...
Retest ...
Etc ... Etc ... Etc ...
Even then if you were up to the task, was it the tweak you did to the hull that got you an extra half MPH or the water conditions /temp of air / other factor ?

Make sure motor is centered on transom, solid motor mounts, new steering system with out any slop, jack plate with small amount of set back, moving weights around battier / fuel tanks / etc.

David CVX-16 · « **Reply #112 on:** November 18, 2014, 11:31:00 AM »

My suggestion is to forget about a pad on a GT150 when you want speeds in the mid 50's and more. The boat is too short for that. Go with a CVX-16. My CVX-16 is stable at 59 MPH and is comfortable to drive at that speed. Others with more horsepower than my 115 HP Johnson, two examples come to mind at 150 HP Johnson and 175 HP Johnson say they can get into the mid 60's.

V153 · « **Reply #113 on:** November 18, 2014, 05:22:54 PM »

As stated a pad would probly not be worth the effort. I'd start off with a hull that already had one. And if ya wanna stay small, and stick with Glastron, the CVX16 is the only choice.

I had the pleasure of piloting David's in Red Wing this summer. I can attest to it's speed and stability. Very impressive.

What kind of RPMs were you turning with that 2 blade prop?

higgins · « **Reply #114 on:** November 26, 2014, 09:10:22 PM »

This is the second time I got my GT-150 out on the water. It was 31 degrees and 5 " of snow. This is on the Des Moines river.

http://youtu.be/isc2LF5g7LA

V153 · « **Reply #115 on:** November 26, 2014, 09:34:32 PM »

Cool!

See? You don't need a pad.

Might wanna work on the splashwell drain though ...

David CVX-16 · « **Reply #116 on:** November 26, 2014, 09:43:28 PM »

Any maximum speed recorded? What prop are you using? Do you dry the boat off in a heated area?

Did you meet Conrad Schmidt? That is a joke. He would also take his boat out in Iowa in the snow and ice.

Something about hitting the lake in the cold weather.

thedeuceman · « **Reply #117 on:** November 26, 2014, 10:08:56 PM »

Dude...
Yer kinda crazy, but it looks like fun

Jason · « **Reply #118 on:** November 26, 2014, 10:14:47 PM »

Awesome video! Nice editing too. Your tempting me to drag the boat out of the garage!

We need speed numbers!

75starflight · « **Reply #119 on:** November 26, 2014, 10:31:14 PM »

Very nice. Just curious how long is the run on the des moines river?