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1960 Evinrude Lark 40 HP boggs under load

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SteveLL7192

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Just got this motor. Comes up to about 1/2 speed and tops out. Advance is working, Carb is clean. If the synchronization of the advance vs the carb is out of sync, could that be a cause? It seems like the magneto makes it's full advance before the butterfly opens.

Thouhgts??

Steve
 
I have the same problem with a 1966 Johnson 60 hp. (Vxl-12r) cleaned carb 3 times, magneto seems to be working properly, brand new fuel. Any ideas? On yours what degree of prop do you have?
 
The timer base hitting its stop first is normal.

Tops out? That normally means hitting full throttle! I'm assuming you mean that the engine "bogs out".... dies out when throttle is applied. If so, assuming that you have spark and compression... that normally indicates that the carburetor is fouled, in which case, clean and rebuild it.
 
The engine does not die. 1/2 speed is the top it will do. Not only does it not die, it runs strong, just does not make full HP. Carb is clean. If the butterfly in the carb is opening late and only comes to full open after the ignition has fully advanced, is that to late for the engine to spin up to full power?

I don't have my service manual with me. Does anyone have the sync procedure for the 1960 40HP Evinrude and if the butterfly is supposed to open with the cam roller, what is the purpose of the metal rod from the throttle shaft to the butterfly linkage and procedure for proper adjustment.

Thoughts?
Steve
 
After the motor has "topped out".....shut it down and use your hand to compare cylinder head temperature on all cylinders....A compression test is certainly needed before performing any other analysis.
 
Now that I have a better understanding of what the engine is doing... hitting one certain rpm and not going any further.

The throttle butterfly should just start to open when the throttle cam roller is dead centered with the scribe mark you see on the cam that is attached to the armature plate.

The synchronization adjustment procedure for the straight rod on the port side of the powerhead that links the armature plate to the throttle linkage follows:

(Synchronization Of Older 2 Cyl Engines)
(Such As The 28, 33, 40hp Etc models )

On the linkage that runs from the armature plate (the plate the coils & points set on) to the carburetor throttle roller, loosen the set screw on the brass collar that you see there and temporarily move it away from the armature plate/vertical throttle arm clevis (clevis is that thing the linkage rod slides through). We'll refer to that vertical throttle arm/armature plate clevis simply as the "clevis" from this point on.

Look at the cam that's attached to the front of the armature plate.... the cam that slides up against the carburetor throttle roller. You'll notice that there's a scribe mark on it. Also notice that at the top portion of the intake manifold there is a raised portion, that top portion forming a point. The carburetor roller should contact the cam and just start to open the throttle butterfly when the scribe mark is dead center with that point.

With the engine in gear (not running of course) have the armature plate advanced all the way (by hand) so that it is up against its stop. Now adjust the brass collar (set screw) on that associated linkage rod so that it is up against the clevis. It should be adjusted so that there is either no play, or just a hairs play between the collar and the clevis.

At this point, the armature plate movement is not advancing the throttle butterfly via the rod movement, but further movement of the throttle control, although the armature plate cannot move any farther, causes the tension spring at the armature plate to allow the vertical throttle arm to move farther which now advances the carburetor throttle butterfly via the rod. When fully advanced (full throttle), the carburetor throttle butterfly should be fully opened (horizontal).

If all else with your engine is as it should be, that should do it.
 
Thanks Joreeves that's what I needed. One more question if you do not mind. Because my Clymer manual is not here with me, I picked up a repair manual from the marina and it's a Seloc. First is a criticism, the manual is not very well written. Not only are the descriptions of procedures vague and make far too many assumptions, the pictures are so dark, you can't see what is being illustrated. That said, I wanted your opinion on why when it is clearly stamped on the flywheel that the points are to be set at .020", their manual calls for .030" and why when all documentation calls for pre 1964 evinrude johnson motors to use 24:1 mix ratio they call for 50:1?

Thoughts?

Steve
 
There is a pointer on top of the intake manifold just off center to the right the carb should just begin to open as the mark on the throttle cam passes that pointer. then take the controls to WOT. The armature plate should be all the way to its stop and the throttle butterfly should be fully open. The link adjustment can be a little tricky, there is a collar with a screw on the linkage from the throttle lever that advances the timing loosen the screw and with one finger fully open the carb and loosen the screw on the collar and push it up tight to the pivot pin on the lever and tighten the screw, that holds the carb fully open at WOT.
http://www.ebay.com/itm/Evinrude-03...ash=item25bbf13046:g:yTkAAOSwr7ZW4zei&vxp=mtr
The collar can get cracked and lose the adjustment just get the screw nice and snug. A dirty hull or if the boat does not get up on a plane it will bog down also. Possible doublebottom full of water will bog the motor down also. Have you done a cylinder drop test? These motors will run real good on one cylinder just pull a plug wire and put it back on quickly while ideling the engine should respond the same on both cylinders if it dies you need to find out why its only running on one cylinder.
 
http://www.marineengine.com/parts/j...manufacturer=Evinrude&section=Lark+Carburetor
The collar is part #16 your carb has the high speed adjustable jet run it at 24:1 mix and change the plugs at least twice yearly. Prestet the slow needle at 1 1/2 turns out and the high speed at 3/4. First adjust the slow needle for the best idle and then point it toward the big part of the lake and go wot and adjust the high speed jet then go back to idle and fine tune the slow. Adjust the slow a tad rich to protect the motor and for cold starts.
 
SteveLL7192 said:
Thanks Joreeves that's what I needed. One more question. Why when it is clearly stamped on the flywheel that the points are to be set at .020", their manual calls for .030" and why when all documentation calls for pre 1964 evinrude johnson motors to use 24:1 mix ratio they call for 50:1?. Steve
Click to expand...

Steve.... I have no idea why a .030 setting would be stated for the points. The point setting is indeed .020 . Set the points by having the flywheel key aligned with the fiber portion of the points (widest setting), then set the points so that a .020 gauge will go through but a .022 will not.

The spark plugs, either Champion J4C or J6C are to be set at the ".030" gap setting.

Some confusion exists at the point where the 50/1 mixture came into existence pertaining to some of the older model engines. The safe bottom line explanation (as far as I'm concerned) is that any engine who's powerhead is equipped with "all" ball, needle, or roller bearings (Mains, Rod Throws, Wrist Pins,) can safely use the 50/1 fuel/oil mixture.

The 50/1 mixture CAN NOT be used on the older engines that had Bushings or Babbitt bearings!

It was recommended that your engine originally used the 24/1 (1qt of oil to 6 gal gas)..... however, since your engine's powerhead falls into the above class (all bearings), you can safely use the 50/1 mixture (1pt of 50/1 oil to 6 gal gas).

My recommendation will no doubt bring forth some criticism but trust me (as the ole carny said), I know what I'm talking about. Seriously, some of my customers have some really old engines (all bearings) and have been using that 50/1 mixture for many years with no problems.
 
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