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Discussion Starter · #1 ·
a buddy of mine is having trouble with his engine. It's a 67 Johnson Super Seahorse w/ electric shift.

The boat will start right up but after a minute or so gas starts shooting out of the front of the carb and it stalls out.

He took it apart down to the carb pulled the bowl off checked the float and pin, everything looked fine/clean Cleaned it anyway put it back together but it didn't fix crap.

This motor was purring like kitten a couple weeks ago when he put it on. He took it to a mechanic to have the a steering adapter put on and once he got it back it hasn't run right. He doesn't think the mechanic ever started it as he only worked on the steering.

We're thinking the carb may need to be rebuilt but everything looks fine. However, neither of are experts by any means, more of trial and error guys.

Anyone have any ideas? Or have a inexpensive but reliable 40 -50 horse they're looking to sell?

Thanks in advance!!!
Nathan
 

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I would strongly suggest getting those carbs rebuilt

I would strongly suggest getting those carbs rebuilt (or doing it yourself). It sounds like the needle is sticking open and not cutting off the flow to the bowl when it is full. That is a very dangerous situation if it gets hot enough to reach the flash point for gas...
 

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The needle and seat have to be replaced.

Bending the tab to put more pressure on the needle and or
polishing the grove worn into the needle that you can't even see without a microscope.
Doesn't Work :)6
(I know I've tried that myself) ;)
 

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I would put money on the diagphram is worn out thus allowing the fuel to flow by flooding the carb out. Try running the motor on a garden hose and while the engine is idling adjust the low speed speed setting just 1/4 turns in at a time then try reving it up and if the engine dies start it back up and slightly turn it the opposite way. This might be something you want to try...
 

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Sounds like you may have some valve/compression issues if you have blow back from the carb. Do you know if the engine has reed type valves? (I am assuming this is a twin cylinder?) You might want to check these but I would start with the following;

I would suggest checking the compression of each cylinder of the engine cold, and hot and compare to engine specs. :)2

Once you have done this you can know how bad your problem may be, rule out a few things, and not have spent much if any $. :)2
 

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Discussion Starter · #6 ·
Thanks for the responses guys. hopefully I'll have so time to work on this weekend with him.
 

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Motor problem

Hope you got the needle fixed. If it was a blowback problem my Son-in-law has a 90 or 91 40 hp Johnson set up for steering that has barely been used since he keeps his boat a 10 hp lake. He took the engine off and it is sitting in his garage. He took the conole out and fuel and oil tank too. Converted his tracker to a more open fighting boat. Let me know if interested and I will pass his number on. TS
 

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Discussion Starter · #9 ·
TS,

I'll ask my buddy probably out of his price range I'll pm you.
 

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Discussion Starter · #10 ·
TS,

Might be interested in that 40 have a feeling it'll be out his price range though. If you could give me his number or a price.

Tight lines,
Nathan
 

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Discussion Starter · #12 ·
Going to break it down again this saturday will post the results. :)2

TS sent you a pm.
 

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I would put money on the diagphram is worn out thus allowing the fuel to flow by flooding the carb out

Usually when a carb needs to be rebuilt the rubber diaphrgams are worn. Shouldn't cost more than $50 for the entire job....
 

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Discussion Starter · #14 ·
will let you guys know Appreciate all the advice. started it on candlewick last weekend it went 50 ft before bogging out.
 

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Fuel pump diaghram is ripped/torn/shot... The boat runs on the Pump-up/prime, but then can't draw anymore gas... Pumping more just overflows the bowls and out it comes... I had a 40 merc that I fiddled with for 2 years... Rebuilt carb, all new fuel hoses, tank and primer bulb... Finally bought the master rebuild kit and did every gasket, o-ring and rubber thingy... BINGO... Air leaks and vaccuum leaks are deadly...
Last I heard Jack, Oldgrayfish, was still running it
 

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"Air leaks and vaccuum leaks are deadly"
Just got a 8 hp roto tiller someone threw to the curb ...
Wouldn't suck gas ,rubber boots on a feeder tube didnt seal anymore.
I tore it down stem to stern and re assembled it. (4 hrs)

The family that left it at the curb wouldn't answer the door when I rang to see if it was truly for free...
They walk there daughter to the bus stop every morning and I
will have her running :lol: and ask Again, Do you want this or can I have it?
No dig really, just Love, You can have it back if you want...
 

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Discussion Starter · #17 ·
My buddy broke the carb completely down this weekend soaked and cleaned every part. The mechanic (bar associate) said he couldn't see anything wrong with it. After putting it back together the flooding and bogging had stopped but it still isn't running right. He thinks it just needs to be adjusted while under load. So hopefully this week he'll have time to get her out and see if leaning her out dials it in. In the mean time will be looking for a used 40 hp.

Thanks again for all the advice will let you know final outcome. :)2
 

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Discussion Starter · #18 ·
Dropped the boat in the water started up but will only idle with the warming lever up and just barely. Could this be a timing or electrical problem?
 

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i would start with new plugs.
 

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Maybe you ought to try adjusting the idle screw on the carb by turning it in a 1/4 turn at a time until your idle runs about 800rpms...
 
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