Need advice on a Johnson 65

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  #1  
Old 06-26-06, 06:11 PM
KLR
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Need advice on a Johnson 65

I need some advice as I am new to boats and outboards. If anyone could point me in the right direction I would SOOOO appreciate it.

-- please forgive terminology mistakes, Im learning --

From the beginning.....
I just bought a 1973 Thunderbird Trihull with a 1973 Johnson 65 HP outboard (original engine?)

Engine's history as I know it......
Last owner used the boat quite alot and had trouble last fall with the cooling system. He found out on the lower drive part of the outboard there is a tube (about 3/4" x 4") that I assume routes the water from the inlets up to the engine(?) had come loose and water was leaking into the lower drive unit and there was a loss of cooling, the engine suffered damage to #2 cyl.

A marine shop did the repairs last October which included.....
Bored cylinders .020 over and rebuilt the whole head unit,
rebuilt the carbs,
tuned the whole engine,
checked the ingnition system, fuel system & everything else.

The boat ran BEAUTIFUL for 4 months till the lower unit went out one day and the boat lost forward & reverse.

The lower unit was replaced and now I bought the boat and cant get it to start.

It will fire up soon as you hit the key but dies in about 3 sec.
If I stay at the engine while someone cranks it and play with the choke & hold the throttle about 1/2 way open it will start and run rough for about 20-30 sec. It appears to be flooding real bad and gas does run out the opening of the caburators. When it does start and run for the 20 seconds it bogs bad and barely runs till it dies.
I thought the floats might be bad or adjusted wrong but they were new and set right. I ran a compression test today and all 3 cyl were EXACTLY 100psi.

Timing is perfect
compression is good
spark is good
carbs are SUPER clean & float is set right
fuel pressure is good

What am I missing?
What would make the carbs leak gas out of the venturis?
What could be making it run SOOO rich & flood out?

Any help would be appreciated

Mike
 
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  #2  
Old 06-26-06, 06:31 PM
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It maybe time to look into the fuel pump and check to make sure those needles are good. The needles are what the float pushes up on to stop the flow of gas when the bowl is full.

It sounds like they are not doing there job.
 
  #3  
Old 06-26-06, 10:19 PM
KLR
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Ok...

I checked the carbs already when I pulled them to check the float adjustment, the needles were new looking and not worn at all.

Could the fuel pump be putting out TOO MUCH pressure somehow? I was thinking if that was possible then the fuel pressure could be high enough to push out the needles against the floats resistance and overfill the bowls thus flooding the carb.
 
  #4  
Old 06-27-06, 02:58 PM
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The fuel pump works off of a vacuum so I doubt it can be causing to much pressure. How hard are you pumping the primer bulb? It does not require alot of pumping just untill it get hard.
 
  #5  
Old 06-27-06, 05:57 PM
KLR
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hey Bill..

After reading the repair manual MANY, MANY times and going over the problem in my head I think I may have an idea.

I "Think" the reed valves may be bad....what do you think?

The engine was 33 years old as were the reed valves.

Hypothetical question.......

You take a 33 year old worn out, low compression engine, add the stress of over heating, then rebuild the engine and bring the compression up to 100 psi. couldnt the old worn out reed valves have split, cracked or broken?

"IF" they did fail then the engine would not recieve a proper amount of air / fuel to combust.....ALSO and most importatly...
When the piston is on a downward stroke it would force fuel / air back out the intake & carbs giving me the leaking fuel from the carbs..

Well........ What do you think?

I will pull the carbs and intake off Friday and check it out, if their damaged I will order then and replace.
 
  #6  
Old 06-28-06, 05:19 AM
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Sound like you may have somethign there. If you would like to talk to experts on johnson/evenrude check this forum out.

http://www.iboats.com/bbboard/bbBoard.cgi
 
  #7  
Old 06-28-06, 10:12 PM
KLR
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Thanks

Thanks Bill, I tried registering there yesterday but the site was down for the day for maintainance I think it said. I know am registered and will ask their advice.

Mike
 
  #8  
Old 06-30-06, 10:11 PM
KLR
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no help for the frustrated...

I tried over @ iboats bill but they werent any help.
I guess I will just have to take it to a marine mechanic, I have a Friday appointment.

---- NEW PROBLEM ---

Today I go out to tinker with it and run a couple of tests....
The darn thing wouldnt crank over. The battery is good but nada.
I checked every fuse I could find but they were all good.

I'm gonna cry here soon
 
  #9  
Old 07-01-06, 09:04 AM
Pwrbait
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Welcome to boat ownership . Boat stand for Break Out Another Thousand. But seriously, don't get to wound up, since you have been working on it, there is the chance you have run the battery down. Even it if shows 12v, it may not have the amps in it to do the job. Do you have access to a load tester? Any auto/boat shop will have one so they can tell you if its ok. When you turn the key, is there voltage to the starter soleniod? If so, try jumping the solenoid to see if it will crank up. If it does, problem solved. Also make sure none of your connections have com loose from all the work you've been doing.
-Chris
 
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