Engine Trouble Please Help 1968 Evinrude 40 hp

kevineltr

Recruit
Joined
Aug 14, 2010
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3
I am having trouble with this motor. It runs perfectly in neutral but when placed in gear it will only troll around. Give it throttle it wont come up to speed it just puts along revs up a little...on its own...every once in a while. I have rebuilt the carb with no change in performance. Again in neutral it runs perfect. Any help would be appreciated
 

chadpcb

Petty Officer 2nd Class
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Jul 24, 2010
Messages
119
Re: Engine Trouble Please Help 1968 Evinrude 40 hp

Three things to check.

1.Compression
2.Spark (Make sure it will jump a 7/16 gap and be bright blue)
3.Proper Fuel
 

kevineltr

Recruit
Joined
Aug 14, 2010
Messages
3
Re: Engine Trouble Please Help 1968 Evinrude 40 hp

its got ...50-1 fuel mix
I will test compression next what should it be?
Not sure about spark? how do I do that?
where do I go from there? and why does this thing rev up fine when not in gear
 

chadpcb

Petty Officer 2nd Class
Joined
Jul 24, 2010
Messages
119
Re: Engine Trouble Please Help 1968 Evinrude 40 hp

Spark Tester from Auto Parts store about 7 bucks
Make sure spark can jump 7/16 gap

Compression as long as each cylinder is with in 10% of each other it should be fine.

REVing up is alot different from putting one in gear placing a load on it.
 

zipo16

Cadet
Joined
Aug 9, 2010
Messages
27
Re: Engine Trouble Please Help 1968 Evinrude 40 hp

spark plug tester or pull the plug, hook it up to the cable and place it near the block and try to turn it over, if you see the blue spark jump from the plug to the block you have spark. try not to shock yourself :p If you have a harbor freight near you they have a inline tester for 5 dollars. or grab one from an auto parts store, they are fairly cheap.
 

tx1961whaler

Vice Admiral
Joined
May 31, 2008
Messages
5,197
Re: Engine Trouble Please Help 1968 Evinrude 40 hp

One cylinder is not firing, almost guaranteed. When it revs up, that's the dead cylinder coming to life for a second or two.
Once you confirm that it is spark using the spark tester or the old school method (pull the plug wires one at a time; the dead one is the one you pull off and it makes no difference....), they flywheel has to come off and the ignition components (coils, points, condensers) replaced.
Instructions:
http://forums.iboats.com/showthread.php?t=294072c
Points gap is 0.020"
Champion plus, J4J, 0.030" gap.
Flywheel torque is 105 ft-lbs.
All parts available cheap here at iboats....
 

kevineltr

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Joined
Aug 14, 2010
Messages
3
Re: Engine Trouble Please Help 1968 Evinrude 40 hp

Thanks a lot folks I should be able to solve this problem now
 
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