Johnson 150 GT?

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spin-a-bait

Cadet
Joined
Mar 26, 2003
Messages
22
My buddy has a '90 Johnson GT and he said that his boat will run 10mph faster when he gets the carb cleaned.But after a few years It will get gummed back up and slow back down.Has anybody ever heard of this problem?
 
D

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Johnson 150 GT?

Why not clean 'em twice and pick up 20 mph?
 
J

jrc27

Seaman
Joined
May 14, 2003
Messages
64
Re: Johnson 150 GT?

i have an 89 johnson gt i just bought and i'm trying to find out the same thing as well as how to clean them
 
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DJ

Guest
Re: Johnson 150 GT?

Those engines have multiple carbs. If one clogs up, it's damaging the engine.<br /><br />To clean:<br /><br />Remove<br /><br />Disassemble<br /><br />Soak<br /><br />Blow out<br /><br />Reassemble.<br /><br />I wouldn't try any of that without a manual.
 
O

ob1jeeper

Petty Officer 2nd Class
Joined
Feb 24, 2002
Messages
167
Re: Johnson 150 GT?

From a 235 GT owner, who found out the hard way (just replaced the PowerHead...) I STRONGLY SECOND djohns response...<br /><br />FIX it NOW $, or fix it LATER $$$$$$$$$$$$$$$...<br /><br />Good Luck, Obiwan...
 
L

ledgefinder

Ensign
Joined
May 2, 2002
Messages
916
Re: Johnson 150 GT?

Old (gummy and/or dirty) gas in permanent fuel tanks cause a lot of these problems (IMHO). Clean the tank(s) and lines when you clean the carbs. I bet half the toasted cylinders out there are due to dirty permanent fuel tanks.
 
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Jack Shellac

Lieutenant Commander
Joined
Aug 7, 2002
Messages
1,661
Re: Johnson 150 GT?

I agree with ledgefinder. Leaving gas in the carbs and tank over the winter without adding stabilizer is a big source of problems. A friend in the O/B repair business makes a lot of money cleaning carbs every spring because of this.
 
M

mjake

Cadet
Joined
Apr 27, 2003
Messages
17
Re: Johnson 150 GT?

I just got rid of my 90 GT150. The one main consideration to keep in mind on these engines is to run the engine decarb cleaner every 50 hours. I had nothing but trouble with that particular model and will never recommend one again. Keep clean gas and decarb on hand. Stay atune to the engine sounds and problems will be less. Highly recommend to disconnect VRO and mix your own oil.I had this boat for 11 years and had three overhauls on it. It was a $$$$$$$$ soaker. BOAT - translates to "bring on another thousand"
 
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Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Johnson 150 GT?

Actually the crossflows were one of the most durable engines around -- providing they were set up right. Set it up to be capeable of 5900 to 6000 rpms with an average load and it will be fine. Lugging that motor in the realm of 5500 and it will coke up regularily. Do the decarbon thing to stay ahead and it might be OK. Set it up to turn less and it will coke up sooner and most likely die a horrible and premature death.<br /><br />They like good oil, are made to run on 87 octane and use Champion plugs. Keep water out of the oil, keep the combustion temps down, feed it a steady diet of good cooling water pressure and it will last a very long time.<br /><br />Good luck!
 
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