C40TLRX link and sync procedure need clarification

[99yam40]

I just happened to re-look at the procedure in my manual and was confused at the sequence that it stated. After adjusting the throttle timing linkage I thought that you needed to have all the butterflies completely closed and synced them at that point, but the procedure says
1. loosen the idle adjustment screw to fully close throttle valve( mid carb),
2. loosen the top and middle carb throttle lever securing screws,
3. adjust the pilot screw to 1 1/2 turns out from lightly seated( does not say to do all 3 carbs that way, but I assume you would at that time)
4. Start and warm up motor
5. hook up tach
6. Adjust the idle stop screw to proper RPM (at this point it will only affect the middle carb)
7. While lightly pushing the throttle lever of the bottom carb fully closed , tighten the top and middle carb throttle securing screws.

So, I would think that this would have the motors idle control running mainly on the middle carb with #1 and #2 still fully closed.

Is this correct?

If it is I have been doing it wrong for quite awhile or I have put down one to many cold ones.

Also, I have not seen anything in the manual as to at what point the throttle (accel) cam should contact the cam follower linkage roller attached to the bottom carb linkage that ends up moving all of the butterflies once they are linked.
Is there any info out there to help clarify any of these adjustments?

I am attaching a couple of the pages out of the manual so you can read them for yourself to see if you get the same thing out of them.

 

[rodbolt]

Re: C40TLRX link and sync procedure need clarification

with that procedure I am amazed it started and ran at all,much less once the initial start timing and cold enrichment ran out.

 

[99yam40]

Re: C40TLRX link and sync procedure need clarification

RodBolt
Could you check a Factory manual on your end and see if what is written in it on chapter 3 page 5&6 is what I have posted. I have an electronic version of LIT-18616-01-81 and I am beginning to wonder about it. Maybe it is an early version and has flaws or miss prints in it.

I have not followed this procedure step by step on my motor. I know I was suppose to do a step by step, but apparently I was too stubborn or though I knew better.
I synced all the butterflies together at fully closed and then adjusted the idel speed.
So am I completly wrong?
Also is there something in your manual about adjusting the throttle (accel) cam contacting the cam follower linkage roller attached to the bottom carb linkage that ends up moving all of the butterflies once they are linked. If so I realy do need to get a different manual

 

[rodbolt]

Re: C40TLRX link and sync procedure need clarification

dunno
let me look and see what I find.
occasionally the factory does send out correction pages to a manual rather than reprinting it.
the roller is the thottle pick up. on yours the pick up timing is the same as the idle timing so set it to a point where its not quite touching the throttle cam.

 

[99yam40]

Re: C40TLRX link and sync procedure need clarification

Thanks RodBolt,
I would really appreciate your looking at your manuals to set me in the proper direction on the idle speed procedure and if there is a correction of the manual I have.

Also thanks for the info on the positioning of the throttle pick up roller. I finally replaced my CDI to correct the idle timing problem I had and I could not find anything in my manual to tell me how or where to set the roller.

Getting the idle timing back into spec (7 DEG ATDC instead of the 14 DEG ATDC I had) allowed the idle speed adjustment screw to be backed out a lot more, closing the butterflies more. Being this motor is a 3rd hand one I am not sure what all has been moved around on the linkage. I still think someone has drilled out the main jets, as I can slip a 1.18 mm rod into the #115 jets. so, I ordered new ones.

Again thanks for the info and I look forward to input on the manual procedure correction

 

[rodbolt]

Re: C40TLRX link and sync procedure need clarification

can you post a pic,airbox removed, of the stbd side of your carbs and ill try to post how I do it.
the manual is a bit confusing.

 

[99yam40]

Re: C40TLRX link and sync procedure need clarification

I will do that tomorrow when it gets light again. Sure hate these short days
Spent the day taking Mom to Dr and dealing with getting her meds. It is definatly not good to get old and I hope there are fish in heaven for us to chase. She sure misses goin fishing.

 

[99yam40]

Re: C40TLRX link and sync procedure need clarification

Rodbolt here are a few pics.
Hope you can see what you need or wanted
Let me know if you want something different.
Trying to learn the best way to shrink pics.
Did your manual have the same wording as mine or was there a correction

 

[rodbolt]

Re: C40TLRX link and sync procedure need clarification

my manual, a bit different than yours, was still confusing.
here is how I do it.
loosen all three shutter adjusting scres.
back off the center carb idle speed adjusting screw unilt the throttle shaft follower isnt touching the screw.
look at the oil pump link arm and make sure its not on the stopper pin.
then make sure all shutters are fully closed.
tighten the top and middle shutter screws.
run the idle adjusting screw down until it hits the shaft follower then an additional 2 turns.
this should get you in the ball park.
once the engine is out of warm up and running at idle adjust the idle screw to obtain the correct idle speed.
then shut the engine off.
move the throttle cam follower on the lower carb against the cam until it almost touches then tighten the bottom shutter screw.

 

[99yam40]

Re: C40TLRX link and sync procedure need clarification

So you loosen all three shutter screws at the first , but do not tighten the bottom one until after you have run it and adjusted the idle?

I had to get a flashlight and go look at the linkage.
So, the bottom one only sets the distance of the cam follower from the cam and the top and middle ones lock all three butterflies in place at the completely closed position (syncronized). Makes sence.

Almost touching would be about .010" or.020"? Or should it be closer?
Should the follower touch the cam at the mark on the cam as the throttle is advanced?

Thanks a million RodBolt you allways have the knowlage and right answers.

Are things slowing down quite a bit on your end of the states from the cold weather or are things still hoppin. It hit 79 degrees yesterday here when the sun came out, but it as been heavy fog for 3 days close to the water here on the middle Texas coast
But it is cooling off angain as I write.

 

[rodbolt]

Re: C40TLRX link and sync procedure need clarification

.010 is plenty.
79 degrees? you suck.

 

[99yam40]

Re: C40TLRX link and sync procedure need clarification

Yea, temp was good, but can't even run down the ditch when you can't see even the front of the boat much less anything else because of the fog.

Do you use a vacuum gauge or manometer when adjusting the pilot adjustment screws on the individual carbs, or do you just go by your ear or a tach? If you do where do you hook it up to?
the only intake manifold port on this motor is where the prime start sends the enrichment and I would guess you could tee into that

 

[rodbolt]

Re: C40TLRX link and sync procedure need clarification

ear and a tach.
normally if everything is correct the factory setting works best.

 

[99yam40]

Re: C40TLRX link and sync procedure need clarification

Thanks I will play with it when it stops raining and this cold front peters out and it warms a bit.
I have not really heard any difference moving it only 1/4 turn either way in the past, but that could have been because of the idle timing being so far retarded and I had to screw down the idle adjustment screw more to get the proper RPM. With the new CDI maybe I will get it all set up correctly it will idle like a new one.