50 hp Johnson no high speed

U

Urbina

Seaman Apprentice
Joined
May 10, 2012
Messages
47
Greetings to all,

OK so yesterday evening i took my boat to the lake to give it a run after removing lots of corrosion.
It turned on fine but when I went to give it was I only got about 5 knots at full throttle.
I cant figure out what's wrong but I know i should be going faster than that.
I kept on getting short burst of power but them it would go back down to 5 knots almost as if the carburetors are getting plugged.
50 Hp on a 17ft Tri-hull
 
C

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,158
Re: 50 hp Johnson no high speed

You might tell us the year and number of cylinders. You might take a compression test and a spark test and report results. 5 knots is not right, such that it is not likely running on all cylinders.
 
jerryjerry05

jerryjerry05

Supreme Mariner
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May 7, 2008
Messages
17,927
Re: 50 hp Johnson no high speed

After a compression/spark test check for water in the fuel.
Then check the fuel pump.
Is it revving up or bogging all the time??
More info?
Removing corrosion?? Where??
 
U

Urbina

Seaman Apprentice
Joined
May 10, 2012
Messages
47
Re: 50 hp Johnson no high speed

Chris1956 said:
You might tell us the year and number of cylinders. You might take a compression test and a spark test and report results. 5 knots is not right, such that it is not likely running on all cylinders.
Click to expand...

Yes you're right sorry
Its a 1981 johnson 2 cycle
2 cylinder
I have good spark with a spark tester and compression is @ 132 psi
 
U

Urbina

Seaman Apprentice
Joined
May 10, 2012
Messages
47
Re: 50 hp Johnson no high speed

jerryjerry05 said:
After a compression/spark test check for water in the fuel.
Then check the fuel pump.
Is it revving up or bogging all the time??
More info?
Removing corrosion?? Where??
Click to expand...

The corrosion was at my terminal points and coil groundings

I m bogging around the whole time with 2 seconds of power burst
Every now and then
 
U

Urbina

Seaman Apprentice
Joined
May 10, 2012
Messages
47
Re: 50 hp Johnson no high speed

I'm thinking i might have to rebuild my carburetor.
think my jets might be clogged
 
fireman57

fireman57

Captain
Joined
Aug 24, 2004
Messages
3,811
Re: 50 hp Johnson no high speed

That and check for spark when it happens with a timing light. Of course you will need a buddy to drive while you do that.
 
U

Urbina

Seaman Apprentice
Joined
May 10, 2012
Messages
47
Re: 50 hp Johnson no high speed

OK so last night i used sea foam in order to avoid rebuilding my carburetors I'm about to take it to the lake and see what happens.
ill keep you people posted and also feed back is welcome thought and opinions thanks
 
U

Urbina

Seaman Apprentice
Joined
May 10, 2012
Messages
47
Re: 50 hp Johnson no high speed

OK gentlemen so after letting the sea foam do its thing i took the boat out to the water.
First it took off like a champ i thought i was in Miami vise lol then i lost power and went down to about 10 mph, a little better but not much.
after that I got some carburetor rebuild kits and rebuilt my carburetors I will put them back on tomorrow and keep you guys posted.
 
U

Urbina

Seaman Apprentice
Joined
May 10, 2012
Messages
47
Re: 50 hp Johnson no high speed

good evening people
after tinkering with my engine and trying to figure out what was wrong i found out all a needed was to rebuild my carburetors.
so know now that i rebuilt them i seem to be running fine although I do need to accelerate my carburetors a bit since it stalls when going into gear.

please remember to update your guys is problem with a solution once you found it.
thank you all who have helped
 
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