throttle cam and cam follower relationship

[opposedtwin]

I have always heard the cam follower should contact the throttle cam where the little line is stamped in the throttle cam. mine contacts it just a little bit early. doesn’t look like you can tell from the picture, but the line is slightly on the starboard side of the follower when contact is made or about 11 o’clock on the follower from the sky view. make sense?

so, where should the tiller grip arrow be lined up when contact is made between the cam and follower? you can see from the picture where mine is at that point.

here’s my problem: in neutral, the motor starts and runs for only a second or two thern dies. if I cheat it into forward and then start it, she will stay running on her own. I had my initial carb settings at 1 1/2 out for the low speed and 3/4 out for the high speed. it idles down pretty well and low, but not low enough to shift it from forward into neutral. this is a 1958 18 hp FD-12.

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[fisherman6]

Actually, the important thing is that the throttle cracks open when the follower is at the mark on the cam. The amount of slop in the linkage can vary quite a bit and the follower can contact the cam well before the throttle actually begins to open. Watch for movement to begin at the throttle arm on the carb. You want that to happen when the follower is at the mark. Does that make sense?

Your carb settings are good for a starting point. Bother will probably end up a little leaner when dialed in, but possibly not. I hope this helps.
-Ben

OldJohnnyRude on YouTube

[johnyrude200]

Those tiller handle grip arrows mean nothing. They were good in the 50’s, hit or miss in the 60’s, and pretty much a novelty from the 70’s there on forward. When you go to start the motor advance the timing to at least 1/2 throttle regardless of what the twist grip word say.

I think things got a little better in the 80’s with the plastic speed reference but at that point all they illustrated was a ‘curve’ and a propeller image. My 2014 Etec follows suite. I don’t even bother to advance the throttle on the new motor because the whole thing is computerized. It starts even at the lowest timing setting. If your tiller grip isn’t original or worn, than those grip indicators mean nothing. Or say that metal sleeve (with the words on it) is loose? Well than we are having a conversation that is about as valuable as a pair of oars in a tornado at sea (hurricane).

Do a link and sync on your motor, the mag plate cam can be adjusted so the cam follower makes contact at the line.

If you know the carb is OK, spark is strong, and compression is NOT low, than this line should still be the right spot. But you can cheat the carb pickup in either direction slightly to tweak performance. When you start talking about mid 70’s 18-20-25hp motors, well, experience is the best teacher in terms of when the carb should start opening up based on an individual motor’s "personality."

[chris-p]

Scott,

YOu will need to pull the cam out a touch. Loosen the right (looking at motor) bolt under the cam. It will have an oblong hole. Pull the cam out, until you see that the carb butterfly starts to move, when the roller hits the hash mark.

[frankr]

Correct starting position is advance the twist grip throttle as far as it will go in neutral. Ignore what the little words say.

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