Topic: 1959 lark 35hp questions – Page 3 – Antique Outboard Motor Club,Inc

This topic has 35 replies, 9 voices, and was last updated 1 year, 9 months ago by mark weaver.

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July 24, 2017 at 4:11 am #62105
garry-in-michigan
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Lifetime Member
DO NOT USE THE TWIST GRIP ON THE TILLER OR REMOTE CONTROL THROTTLE. Disconnect the remote control. Turn the vertical shaft on the starboard side of the motor so the magneto base touches the stop. The roller is still against the cam and the butterfly valve is almost half throttle. NOW you place the collar and tighten the screw. Further advancing the tiller grip pushes the collar to fully open the butterfly valve in the carburetor. . . 🙂
July 24, 2017 at 1:17 pm #62121
lindy46
Participant
US Member
Yup – you can’t adjust the collar with the throttle fully advanced.
July 24, 2017 at 2:43 pm #62127
opposedtwin
Participant
US Member - 2 Years
quote lindy46:

Yup – you can’t adjust the collar with the throttle fully advanced.

So where SHOULD the throttle be when making these adjustments?
July 24, 2017 at 3:40 pm #62130
frankr
Participant
US Member
quote opposedtwin:

quote lindy46:

Yup – you can’t adjust the collar with the throttle fully advanced.

So where SHOULD the throttle be when making these adjustments?

mag plate against the stop as previously said. But not cammed over the spring. As Garry and others have said.
July 24, 2017 at 5:29 pm #62134
opposedtwin
Participant
US Member - 2 Years
Ok. Thanks thanks for trying for to help guys. Of course I still don’t understand. I don’t know what "not cammed over the spring means.

I did make the adjustments with the mag plate against the stop and stated that clearly. Maybe I’m misunderstanding the relationship between spark and throttle here. The reason I’m continuing to pursue this issue is because I still don’t understand. I was hoping there was another way it could be explained.
July 24, 2017 at 6:16 pm #62136
frankr
Participant
US Member
OK, let’s give it one more shot. Refer to the parts blowup below. There are two things that open the carburetor butterfly shaft, the roller on the front and the fuel saver rod on the side. They are two separate issues. I am going to try to explain the fuel save rod.

The vertical throttle shaft on the side of the motor moves the brass link #6 in the picture. #6 is attached to the armature plate by a spring, #1.
as you move the throttle control, the link rotates the armature plate until it bangs up against the boss on top of the cylinder. When that happens, it is at Cruise Throttle position and the collar/rod has not yet opened the carburetor—but should be ready to.

Further movement of the throttle control and link compresses the spring #6 and it snaps over center (what I called cammed, probably not the best choice of words). As it snaps over center the collar and rod kicks the carburetor to horizontal position. THAT is wide open throttle position, and seems to be what is confusing you.

So, it is very simple. With the control at cruise throttle position the pivot pin #8 should be just touching, but not pushing on the collar #9-10. Further movement of the control makes it snap over center and pushes the rod & carb to WOT position.

I may not be the best with words, but that’s about the best I can say it.
July 24, 2017 at 11:30 pm #62150
lindy46
Participant
US Member
quote opposedtwin:

quote lindy46:

Yup – you can’t adjust the collar with the throttle fully advanced.

So where SHOULD the throttle be when making these adjustments?

Open the throttle until the mag plate hits the stop – NO FURTHER. The throttle will be about 2/3 open at this point. NOW adjust the collar as described previously (collar just touching the pivot pin), and tighten it down. Now, as you advance the throttle further the rod takes over as the collar butts up against the pivot pin, to fully open the carb butterfly. The cam roller will have nothing to do with it. In fact, the roller will actually push away from the cam and not be touching it.
August 8, 2017 at 10:48 pm #62695
opposedtwin
Participant
US Member - 2 Years
I had to put this adjustment issue on the back burner for awhile. I went to California and Tomahawk but now I’m back trying to figure this out. Thanks for the help so far.

So I think I have an idea what the problem is. By the time the armature plate bracket (D) is up against the stop, I’m already at full throttle and there’s nothing left to push the carb plate to the fully horizontal (and thus fully open) position. So when you guys are saying th adjustment should be made at "2/3 throttle" or "cruising throttle", I’m already at full throttle or WOT. So why would that be? I believe I have the carb and spark properly synchronized. In the picture below, the mark on the cam is lined up with the index cast onto the block and the cam follower is just touching the cam.

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August 9, 2017 at 2:28 am #62700
opposedtwin
Participant
US Member - 2 Years
Also I realize improperly meshed throttle/pinion gears could be to blame but i think they are meshed properly. If you see something wrong, please let me know.

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August 9, 2017 at 2:53 am #62702
vintin
Participant
There are adjustments either on the connector from the roller to the throttle butterfly or under the flywheel the machine screws that hold the brass cam in place. You need to adjust until the throttle butterfly is just beginning to open when the roller lines up centered on the hash mark on the brass cam. It is way off!
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