150gt ?

J

James R

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Going to look at a so called 1994 150GT tomorrow with a view to buying it. I dont yet have the model and serial number but can anyone give me an idea as to what years Johnson made the 150GT model.
 
tashasdaddy

tashasdaddy

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Re: 150gt ?

quite a few.
BUYING A USED MOTOR

overall condition, condition of the place you are buying it from, usually tells you how they care for things. compression 100 + psi, and within 10% of each other, good strong blue spark, no water in the lower unit oil. look for discolored paint, (sign of over heat at
one time, also scarred up bolts, as why. have them start it. if they fail to put it in a barrell or tank, or on muffs, or in the water, to start it they don't know what they are doing. best yet is to take it for a 30 min to 1 hour test run. also if remote controlled motor, the controls should come with it.
 
J

James R

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Re: 150gt ?

Tasha thanks for the swift reply. I do all the tests but thanks for the input.
I have numbers now but they seem to be meaningless on BRP. Anyway they may mean something to you. Give it a shot for me please.
These are off the plate so I'm told.08552292 and MAA-520584.
Thanks
Jim.
 
HighTrim

HighTrim

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10,486
Re: 150gt ?

In their day, the GT model was a high performance bass boat engine. They actually put out about 10% more HP than the normal 150 hp (usually around 165-170hp at the prop). They did this through components of the 175 such as heads and carbs (1 3/8"). They have beefy lower engine mounts for high speed steering. The decals are a bit different, along with the cowl itself, to increase the motors breathing capacity I believe. It may also have the 35 amp alternator.

As stated, check the compression (usually about 95 psi per hole, but more importantly the difference between cylinders) and give her a good run before buying.
 
tashasdaddy

tashasdaddy

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Re: 150gt ?

you don't want more than 10% between high and low. number make no sense.

on the newer motors, they used a plastic sticker, on the transom mount, some have come off, and the welch plug on the block only has serial #, which dealer are only ones privileged to. but dealer can tell you when built.
 
E

emdsapmgr

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Dec 9, 2005
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11,551
Re: 150gt ?

Not sure just what engine you are looking at. The last year for the XP/GT crossflow in the 150 hp range should have been around 1991.
They carried a model number of 150S. (They did continue to make the XP/GT name in the big bore 90 degree 200 loopers beyond that.) If it is a 150 hp 1994, then it is a 60 degree looper, which did not carry the GT/XP designation. That year these special 150's were called INTRUDER and FASTSTRIKE. These carried a model number of 150GL. These engines were similar to the XP/GT models and had the higher horsepower mentioned by Hightrim in his comment. See if you can find out the model number off the transom bracket or swivel bracket.
 
james williams

james williams

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Jul 22, 2006
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Re: 150gt ?

I thought ALL the Johnsons In the 80s through lower 90s 150hp were GT.That souped-up 150 were j150ST------. on the model number.
 
E

emdsapmgr

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11,551
Re: 150gt ?

OMC made a basic 150 and the XP/GT 150 from 1983 through 1991. While the powerheads look the same, they are not. Technically they are all 150 hp, but the BIA rating Association permitted a 10% leeway and still be considered 150. These XP/GT versions put out 162-165 hp at 5000 by using 175 heads and carbs.
 
J

James R

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Feb 1, 2007
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Re: 150gt ?

First I want to thank all of you for a wealth of information and as always forum members have done a great job.
I took a ride, just170 miles there, no biggie, and took a looksee. The "excellent condition" motor and rig turned out to be junk. So no deal there.
Thanks once again your help is most appreciated.
 
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