79 Johnson 140 hp running 22,000 rpm

DavidKnapp

Cadet
Joined
Jan 27, 2012
Messages
17
Rebuilt both carbs ,thinking that was my issue,put a water separator in system,the motor will only run 22,000 rpm max.
There is no mix fuel air valve to adjust,checked compression 105 on three cylinders 110 on other ,all 4 plugs are very wet after running ,is there a way to adjust the carbs ,or is it a something electrical ?
 

wired247

Lieutenant Commander
Joined
Oct 8, 2011
Messages
1,557
Re: 79 Johnson 140 hp running 22,000 rpm

22,000? Ok Its too easy.


Why did you rebuild the carbs? Check your spark, make sure your floats are set right.
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: 79 Johnson 140 hp running 22,000 rpm

22,000 rpm, please explain ??
 

mark1961

Ensign
Joined
Apr 30, 2007
Messages
940
Re: 79 Johnson 140 hp running 22,000 rpm

You might need to subtract about 20,000rpm from that.....
 

SparkieBoat

Captain
Joined
Aug 17, 2009
Messages
3,643
Re: 79 Johnson 140 hp running 22,000 rpm

check spark..also make sure you connected the water separator properly and not backwards or something.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 79 Johnson 140 hp running 22,000 rpm

The carbs on that engine have fixed jets from the factory. Non adjustable, but they can be swapped out-but that's usually not necessary. Check for spark on all 4 cyls first-it's possible the engine is only running on 3 cyls. You might retest with another compression gauge. Usually the compression on these 140's is 135+ on each cyl. Does it have the original heads on the engine?
 

DavidKnapp

Cadet
Joined
Jan 27, 2012
Messages
17
Re: 79 Johnson 140 hp running 22,000 rpm

As far as I know these are factory heads,all cylinders have spark,I'll try a nother compression gauge ,still with that compression would that make my plugs wet after running ,still makes me think of a fuel issue ,
Reason I rebuilt the carbs was cause it wasn't running right and it sat from last summer in july.
Could the floats be bad I did not replace them?
 

Bob_VT

Moderator & Unofficial iBoats Historian
Staff member
Joined
May 19, 2001
Messages
26,019
Re: 79 Johnson 140 hp running 22,000 rpm

It could be as simple as a blocked passage in a carb or two. Your compression is fine.

How old is the fuel?

I would have to agree it might be an electrical problem since the V-4 motor will run on only 1 cylinder!!

A quick solution would be check the spark.

oh and BTW ........... 2200 not 22000 rpm is probably correct ;)
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 79 Johnson 140 hp running 22,000 rpm

Wet plugs is usually a sign that the carbs are flowing fuel to the cylinders. It could also be a sign that the plugs are not firing under compression. Try using an inductive timing light to check for spark on each plugwire when running it on the garden hose.
 

SparkieBoat

Captain
Joined
Aug 17, 2009
Messages
3,643
Re: 79 Johnson 140 hp running 22,000 rpm

use a spark gap tester..should spark across a 7/16 gap..instructions in my sig below.
 
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