F50TLRW Carb Sync Question??

[larrye44]

I bought a boat from a man that had a carb job done on the engine, but they were not sync'd. It is a 1998 year model. He was in the Marine Corps and was gone for a while and he left gas in the carbs. The mechanic said he didn't have the gauges and if he wanted it sync'd to take it to the dealer. The engine runs okay, but sputters ever so often. I know they are not in sync. I'd like to sync the carbs myself. I have made a manometer for the job.

However, they are so far out that the #1 and #4 carbs pull the transmission fluid out of the jars before I can make adjustments. Is there a way I can get to a starting point with the adjustments? I know on small engines it recommends turn the adjustment all the way in and then back out 1 and 1/4 turns. Then find adjust from that setting.

I also know that there are those out there that say "take it to the dealer". I like doing things myself. I like the sense of accomplishment. I like learning new things. This is something I would like to do myself, but I also know there are things that may be beyond my scope. I don't feel that's the case here as I have read on this forum where it has been recommended to but the gauges from Yamaha and sync the carbs yourself (even though they are expensive).

This manometer should get the carbs a lot closer that they are now. I have the shop manual for this engine and I know that the #2 carb has to be set with a little more vacuum than #1 and #3 has to be set with a little more vacuum that #2, and so forth. I just need a starting point where I can fine tune them before the two middle jars are pulled empty. I can't use more tranny fluid as it just gets pulled to one and four jars and then to the carbs pull it up and through the carbs (lots of smoke). Thanks for the help everyone. Larry

 

[rodbolt]

Re: F50TLRW Carb Sync Question??

then your simply going to have to buy the correct 4 channel manometer.
the air fuel screws DO NOT get touched until AFTER syncing the throttle plates. plate sync is done at 1100 RPM for that reason.
problem is you have to rack the throttles a few times which means either breaking down and resetting your manometer or every time you rack the throttle it will suck out all the fluid.
same as the old 4 channel yamaha manometer with replaceable mercury.
its also why I bought the tech mate vacum mate.
there are a few others for about 150 that work but require some math as the vacum guage read out is not in Hg or mmhg.

 

[larrye44]

Re: F50TLRW Carb Sync Question??

Well, rodbolt, I guess I was wrong on this one. It's probably going to be cheaper to take it to the dealer than to buy the gauges. The only problem with the dealer in my area is two people I work with have taken their motors in to them and they came back worse than before. I buy stuff from them and they are great people, it's just their service department is not the best. I'll have to take it in and take my chances. I sure appreciate it and I know your opinion is valued on this forum so I have my answer. Thanks, Larry

 

[rodbolt]

Re: F50TLRW Carb Sync Question??

if the carbs are infact clean then setting the link and sync is less than 30 minutes.
use the Yamaha dealer locator function and search for a dealer near you that has a master tech or at least 4 stroke systems and fuel systems certs.
proplem is out of all the 4 stroke carbed setups yours is one of the most difficult to properly set up.
my tech mate setup set me back about 700 dollars but I use it for a living and dealing with multi throttleplate EFI and multi carbed 4 strokes there is simply no way around it.

 

[larrye44]

Re: F50TLRW Carb Sync Question??

Thanks, rodbolt, that's what I'll do. Larry