Topic: 1959 lark 35hp questions – Page 2 – Antique Outboard Motor Club,Inc

This topic has 35 replies, 9 voices, and was last updated 2 years, 6 months ago by mark weaver.

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July 6, 2017 at 3:32 pm #61103
vintin
Participant
Comments on the fuel saver adjustment.

With my 1957 35hp Johnson there seems to be a difference in how it runs and sounds in these two scenarios:

1) If I slowly advance the throttle until the boat is moving about 20 mph.
2) If I full throttle it and then back off of the throttle until the boat is moving about 20mph.

This motors sounds like it is under a lighter load if full throttled and then backed off. I believe there is a slightly different spark advance setting in the two scenarios. I’m not one that goes in for powerful ‘hole shots’ so often I creep up on the operating speed at which I want to cruise. Most often I do creep up to my desired cruising speed of 20mph and then give it a second or two of full throttle then back off. This motor seems much happier operated this way.

If anyone has an explanation of what I’m experiencing, I’m all ears. I’m into long cruises and the throttle may stay in the same setting for an hour or more and I can’t help but think there is a major difference in what is taking place inside of the motor.
July 6, 2017 at 4:11 pm #61110
outbdnut2
Participant
US Member
Hey VinTin,

What you described is exactly the way the fuel saver works. Back off the throttle slightly at higher throttle settings and it backs off the carb without backing off the spark advance. Since you are already planed off by then, you can back off the carb a bit without losing much speed, and you gain gas economy.
Dave
July 23, 2017 at 1:44 am #62055
opposedtwin
Participant
US Member
Ok, I have a manual and followed the insructions on adjusting the fuel saver rod set screw. I followed the instructions in this picture i posted here. But now, when I advance the throttle all the way and the spark advance is at the maximum (ie: the armature plate bracket (D) is resting against the boss (F) on the block), the carb butterfly is somewhere between vertcal and horizontal. Under no scenario does the butterfly now get to be horizontal. It should be horizontal at wot, correct? Or maybe a bit less than horizontal because of the adjustment i made employing the fuel saver option.

In the third picture, it looks like i may be missing something like a return spring? From my parts catalog, it’s hard to tell what might connect to that hole in the cam follower due to the exploded format. Could a missing spring or unconnected linkage (if that is what’s going on here) be to blame for the troubles here?

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July 23, 2017 at 12:06 pm #62067
bill-mcnamara
Participant
Canada Member
I believe that where you’re pointing to is where the locking lever assembly attaches, to prevent FAST starts.
July 23, 2017 at 12:35 pm #62068
frankr
Participant
US MEMBER PAY BY CHECK
quote opposedtwin:

Ok, I have a manual and followed the insructions on adjusting the fuel saver rod set screw. I followed the instructions in this picture i posted here. But now, when I advance the throttle all the way and the spark advance is at the maximum (ie: the armature plate bracket (D) is resting against the boss (F) on the block), the carb butterfly is somewhere between vertcal and horizontal. Under no scenario does the butterfly now get to be horizontal. It should be horizontal at wot, correct? Or maybe a bit less than horizontal because of the adjustment i made employing the fuel saver option.

See #3 in the instructions. With the armature plate against the stop loosen the collar and let the rod go where it wants to go. Then slide the collar into proper position, just touching the pivot pin, and tighten the screw. Now, as you advance the throttle control most of the movement will be moving the armature plate until it hits the stop. Then, and only then, should the pivot pin contact the collar. Further movement of the throttle control kicks the lever over center and opens the carb butterfly to horizontal.
July 23, 2017 at 1:03 pm #62070
chris-p
Participant
As Bill stated, your rod from your locking lever on your recoil should attach there.
July 23, 2017 at 2:28 pm #62074
lindy46
Participant
I believe #1 in your instructions is misleading. You slide the collar into position when the armature plate is just at the stop (probably about 2/3 throttle). Then, further advancement kicks the spring control over to open the butterfly. At this point, the cam follower roller is out of the equation. Correct me if I’m wrong?
July 23, 2017 at 7:38 pm #62086
garry-in-michigan
Participant
Lifetime Member
No, you are right. With the grip on the tiller in the "Fast" position the carburetor throttle valve (Butterfly valve) would be wide open (Horizontal). The adjustments are made with the vertical throttle shaft which changes the magneto position.

The carburetor throttle valve is controlled by the magneto cam right up to the point that the magneto hits the stop. Then it is held against the stop by the spring in the connecting link while the rod takes over from the cam to fully open the carburetor throttle valve. . . 😉
July 24, 2017 at 3:07 am #62101
opposedtwin
Participant
US Member
This is ridiculously confusing. I adjusted it using the steps in the picture and it would only run at about 1/2 rpms. I released the collar screw and re-tightened it somewhere in the middle and it achieved higher rpms. But i can’t tell if i’m getting the benefit of the "fuel saver" feature. I’d really like to figure this out.

So, in following steps, I did the following:
-this motor is hooked up to remote controls so I moved the throttle lever to the fastest position.
-checked to make sure the armature plate bracket was against the boss on the crank case. It was.
-I loosened the set screw in the collar and slid it against the pivot pin.
-I tightened the screw in the collar

All this was done with the throttle lever in the fastest position. When i went out on the water (as stated above), it only achieved about 1/2 of typical rpms.

So what am i doing wrong?
July 24, 2017 at 3:14 am #62103
opposedtwin
Participant
US Member
quote FrankR:

quote opposedtwin:

Ok, I have a manual and followed the insructions on adjusting the fuel saver rod set screw. I followed the instructions in this picture i posted here. But now, when I advance the throttle all the way and the spark advance is at the maximum (ie: the armature plate bracket (D) is resting against the boss (F) on the block), the carb butterfly is somewhere between vertcal and horizontal. Under no scenario does the butterfly now get to be horizontal. It should be horizontal at wot, correct? Or maybe a bit less than horizontal because of the adjustment i made employing the fuel saver option.

See #3 in the instructions. With the armature plate against the stop loosen the collar and let the rod go where it wants to go. Then slide the collar into proper position, just touching the pivot pin, and tighten the screw. Now, as you advance the throttle control most of the movement will be moving the armature plate until it hits the stop. Then, and only then, should the pivot pin contact the collar. Further movement of the throttle control kicks the lever over center and opens the carb butterfly to horizontal.

Frank: I’m with you to this point (the part in red) I think. But how do I advance the throttle at this point? My throttle lever is already in the fastest position and the armature plate bracket is already up against the boss on the crank case.

And then the part I made green: where does this "further movement" come from?
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