What exactly does Link & Sync Involve?

[handle]

I have a carbureted 4 stroke and am trying to find out what exactly link and sync entails and can I perform this procedure my self.

 

[Grub54891]

It involves linking carbs to timing. Each motor has its own procedure. Yeah you can do it yourself, but get a factory manual,follow it to the letter. If it's off,it can cause poor performance,or worse. I've sink/linked many motors,and the difference in performance is quite amazing. Some of the customers ask what did you do? It never ran that well before. I tell them just a sink/link,and don't mess with the linkages anymore....but they do anyway....lol

 

[handle]

Thank you for your response, When you sync carbs do you actually reset the timing or are you setting all three carbs to open according to the vacuum gauges at said proper idle speed ? This is actually an 06' Yamaha TLR 40 but nobody will respond to me on the Yamaha forum, Thanks again.

 

[Grub54891]

You are setting the carbs linkages to open all at same time,so the power is equal through all the cylinders. Then you set the linkages to the timing plate so it advances at the right time to get maximum power throughout the power range. If nobody messed with the timing plate it should be ok. But that's why you need the manual. It'll tell ya the correct procedure for your motor,and how to set the timing for it. i haven't had to do any yammys in quite some time. Mostly johhnyrudes in my neck of the woods.
Did someone mess it up,or are you just checking it to make sure it's right?

 

[handle]

The motor hasn't run the best since new. Ethanol has been a real problem with my motor. I'm shooting at the hip but I believe the manufacture is leaning these motors out so much that the pilot jets are clogging up prematurely. To answer your question I have had an independent boat mechanic tear down and clean the carbs and re link & sync the motor. Ran better but not right, he re cleaned the carbs again. Needed cleaning the next year, did it my self and found two out of the three pilot jets dirty. Increased the pilots from #38 to #40 re cleaned all and had improvement. I did not link & sync but did not touch any of the original settings. Now reaching out for advice and trying to better understand the situation before I take this motor to a dealer. I have mechanical back round but not in this field. As of now the motor runs good in the bucket but have not lake tested yet. The first mechanic stated that the pilot jets are to small and to increase them even more than I have, does that sound like a possibility you would entertain. Appreciate the advice. Maybe the hammer would fix it!

 

[Grub54891]

Well then.hasent been right from the beginning. Then the dealer should have made it right.#1, changing jetting because they clog up is the wrong move,motors are set up the way they should be from factory,changing things just makes it harder for any tech to figure out what the real problem is.Being sure the fuel is clean is the number one priority. A fuel water separator is in order,along with clean fuel tanks. In my honest opinion,ethanol has no bearing on issues with most boat motors,except the fact it eats up gunk in the tanks,and non ethanol fuel lines. I myself run ethonal,no problems,except the end of season,I run non ethonal, just as a safety bumper. Jet it properly,synk/link,clean fuel,carbs will not plug up. Is your mechanic marine or ?? Keep us posted on results.