1990 Johnson 90hp outboard...need advice

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lowcountryboil

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I have a 1990 Johnson 90hp outboard that lost power while at WOT pulling someone on a tube....i shut it down then it would not start at all...... This thing ran great until then. I bought the boat used from someone and never had anything checked other than compression which was good...it sat all winter outdoors and finally i had scrounged up some money to have it looked at and the mechanic said that the motor is seized and that he could not even get to break loose.....my mechanic said that it would take an engine rebuild at a cost of at least $1500.....does anyone have an idea of what the problem is and if its worth fixing?
 
oldcatamount

oldcatamount

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Re: 1990 Johnson 90hp outboard...need advice

How do the cylinder heads look? Is the paint burnt and blistered? Sounds like a severe over-heat (probable cause- bad impeller). Is it worth fixing.....well, it's over 20 years old...probably worth around 1800...yup, I'd re-build it.
 
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wired247

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Re: 1990 Johnson 90hp outboard...need advice

You can buy a used motor for that much. Then you have a used motor that may be OK for a few seasons. It might last longer. It might not. You can spend the same amount and rebuild your current 90 and then you'll have a "new" 90 that will last a very long time. 90's are good, long running relatively fuel efficient engines. Or you could buy a new engine for $10K that gets very good gas mileage and starts right up every time. You can buy a LOT of gas for the $8500 difference between rebuilt and new and put up with a little tempermentalism. Change those pump impellers every couple of years. They're cheap insurance.


FWIW you can rebuild it yourself for well under a thousand. Extremely simple engines to work on.
 
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boobie

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Re: 1990 Johnson 90hp outboard...need advice

Possible the lower unit froze up on you and not the power head.
 
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lowcountryboil

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Re: 1990 Johnson 90hp outboard...need advice

My mechanic said that when he pulled the spark plugs that one of them was rusted so I guess that means moisture is in the cylinders.....how does that change the prognosis.
 
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lowcountryboil

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Re: 1990 Johnson 90hp outboard...need advice

Why keep it to yourself........give me an honest answer if you have one.
 
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boobie

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Re: 1990 Johnson 90hp outboard...need advice

Guess it's a p/h prob with the rusty spark plug.
 
metriccrescentwrench

metriccrescentwrench

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Re: 1990 Johnson 90hp outboard...need advice

tx1961whaler said:
I have an opinion of what the problem is, but I'll keep it to myself.
Click to expand...

Wow, that's definitely a helpful reply. If I was going to be that forthcoming with information I believe I'd have just kept my hands off my keyboard.

If there's rust on the plugs that's definitely not good. Just for the heck of it pull the heads and take some photos of the heads, pistons, and cylinder walls. It's probably not going to be good news, but someone here can at least offer advice on whether or not it might be worth rebuilding it.
 
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lowcountryboil

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Re: 1990 Johnson 90hp outboard...need advice

no matter what the heads, cylinders, etc... are good or not, wouldnt be worth it to have it rebuilt for $1500 considering its basically a new motor at that point and with proper maintenance and upkeep it should last another 20 years?......I can pull that motor and put it on another boat down the road........your thoughts
 
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tx1961whaler

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Re: 1990 Johnson 90hp outboard...need advice

metriccrescentwrench said:
Wow, that's definitely a helpful reply. If I was going to be that forthcoming with information I believe I'd have just kept my hands off my keyboard.
Click to expand...
What I was going to type was not very nice. Neither was the reply that I just typed, but deleted after I wrote it.
Happy Easter!
 
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boobie

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Re: 1990 Johnson 90hp outboard...need advice

Must be a REAL BAD day !!
 
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tx1961whaler

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Re: 1990 Johnson 90hp outboard...need advice

wired247 said:
Someone having a bad day?
Click to expand...
No, not at all. I just always try to keep it nice and friendly here. I usually hit the "Cancel" button if I write something that could be taken the wrong way, but sometimes I just delete it and throw a 1 liner in there.
Anyway, back to the motor, pull the lower unit to make sure it's not locked up, but that seems unlikely given the plug condition. Then pull the head off and inspect the cylinder walls. If it looks like water is getting in there, then check the exhaust manifold and gaskets.
I would not be real hopeful if the powerhead is seized up that tight. Could be major damage in there.
 
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tx1961whaler

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Re: 1990 Johnson 90hp outboard...need advice

Not hard at all.
Good luck with your motor!
 
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tx1961whaler

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Re: 1990 Johnson 90hp outboard...need advice

Now that was uncalled for.
I was originally going to blast the OP for blowing up his own perfectly good motor with his lack of maintenance skill and running the pee out of a newly acquired motor all season without even checking the first thing on the motor. I refrained from doing so.
Would that have made y'all happy if I would have just told the guy that his motor's problem was HIM?
 
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