1984 Jonson 35hp - Timing/Throttle/Carb sync

[Boomhauer]

Long story short, picked up a Tracker Guide V14 with a 1984 Johnson 35hp 2 cylinder 2-stroke (J35RLCRR). The low speed needle retaining ring had disintegrated, so while I was replacing that I went ahead and removed/cleaned/rebuilt the carb. Now I have everything back together and am trying to get everything synced/adjusted properly.

I am referencing the OMC manual as well as the Seloc manual 1302 for these engines.

I am trying to set the "Throttle Pickup Adjustment" and "Throttle Control Rod Adjustment" according to the OMC manual. However, each of these settings seem to contradict each other. I feel like I am misinterpreting something in the instructions.

For example:

Scenario 1
[1] Adjust the throttle control rod such that the carb begins to open just as the cam follower is between the two marks on the spark advance cam (this seems most important)

The cam follower leaves and comes back to the cam right between the marks as the throttle is opened and closed. At WOT the throttle lever is not contacting the hard stop against the engine block, so the carb throttle valve tries to rotate past wide-open, and eventually begins binding the throttle rod as I rotate the throttle control.


Scenario 2
[1] Advance throttle lever to stop against the engine block by hand (engine in forward gear)
[2] Manually open carb throttle valve to wide-open position (blade perfectly horizontal)
[2] Set throttle adjust collar screw against the nylon pivot block at this position

Once I have all that set, the cam follower comes down way too soon as I let off of the throttle. In other words as the cam follower comes down while the carb closes, it contacts the spark advance cam way to the left of the two marks where it is supposed to contact between as it comes down. Does the throttle lever need to be against the stop on the engine block in order to properly advance timing at WOT?

I hope this explanation made sense. I am trying to figure out how to add pictures for reference.

All in all, the main questions I have are:
[1] When I turn the tiller throttle control to WOT, should the throttle lever stop against the engine block?
[2] Does the throttle lever need to be stopped against the engine block to fully advance the timing?
[3] **Is the cam follower supposed to leave/contact the cam between the two marks as the carb begins to open/close AND the throttle control rod be set such that the butterfly valve is at WOT with the throttle lever against the engine block? I do not see how this is physically possible on my engine.**

I'm just worried that even though I have it adjusted so that the cam follower leaves the timing advance cam right between the marks as the carb begins to open, that I am not fully advancing the timing as it should, since the throttle lever is not contacting the engine block at WOT. And the fact that I am pushing the carb's throttle valve past horizontal.

But at the same time, If I adjust the throttle rod collar screw so that the carb throttle valve is wide-open at the same time that the throttle lever is against the hard stop on the engine block, then as I release the throttle the cam follower comes down "too soon" and is no where near the two marks that is supposed to be between when it contacts the cam. I know there is the adjustment on the lever where the throttle rod connects to the carb, but there is no where near enough adjustment to make up the difference that I am seeing.


Sorry for the drawn-out post, just trying to include all possible information.. I am continuing to research this and figure it out, as well as searching through this forum and others for any relevant information.

Thanks in advance for any info on this!!

[Boomhauer]

Still figuring out how to get pictures in my post. Looks like I can't attach them directly?

Youtube example of what I'm doing. Makes sense when I watch it, I can get my cam follower to act like that. However the throttle lever is not bottoming out on the engine block, so it looks like it's not advancing spark enough at WOT, as well as putting excess pressure on the carb's throttle arm after it goes past fully open (if I keep applying throttle pressure). The instructions say WOT with the throttle should line up with WOT on the carb. Ok that makes sense. But if I make that adjustment work properly, then the cam follower isn't lining up with the marks on the cam when it starts to move down. Scratching my head here. Definitely missing something.

https://www.youtube.com/watch?v=za6N...nnel=OmFishing

[Boomhauer]

After more research I am comfortable saying the most important of the carb/timing sync is having the cam follower leave/contact the cam right between the marks on the cam. This should keep spark advance synced with throttle position/engine speed. I have seen and read that you may need to adjust this slightly in some cases depending on the engine. Mine seems to work when set right between the marks.

Regarding the procedure for Throttle Control Rod Adjustment, still not sure how you can have the above set properly, and be able to rotate the throttle lever to the stop on the engine block without binding the throttle shaft. That's where I'm left confused and feel like I'm missing something. Or there is something mechanically wrong with my system.

Took it out yesterday to try to get the carb adjusted. There is a lot of play in the throttle control which is making it hard to get the idle fine-tuned. I also need to replace the bent idle stop screw. (acts more like a cam rather than a linear adjustment due to the wobble as it rotates, for example 1/4 turn doesn't always yield same amount of adjustment)

I hooked up a tachometer to try and monitor RPMs. According to that, I was able to idle around 700-800 rpm in neutral, probably lower if I spent more time on it. At WOT it was topping out at roughly 4900 rpm, manual says it should be at least 5200 (up to 5800 I believe). Then again I have not verified my tachometer. It is the type where you wrap a signal wire around the spark plug wire. I am going to get a photo eye tachometer that looks at a marker on the flywheel for a comparison measurement. Previous owner had put a new prop on it, I believe it matches factory prop specs but I have not verified that.

At the end of the day I think I was over-thinking it, though I wanted to be as thorough as I could when setting these adjustments. The only thing left is to verify the timing/spark advance at WOT and get that adjusted to the factory spec of 30 degrees advanced.

[Boomhauer]

Pretty sure I have my issue figured out.

Looks like the spark advance stop bolt also serves as the high speed throttle stop. (feel free to correct me if I am wrong on that) Duh. Looking back, it should've been obvious, but with my inexperience it didn't click right away.

(I was confusing the throttle lever itself contacting the engine block with the throttle/timing cam contacting the spark advance stop bolt as the high speed throttle stop)