1983 60C set up

[redexredex]

Hi, I have just finished rebuilding a 1983 60C 2 cylinder 2 stroke. All adjusted by the book (carbs vacuum balanced). Seems a little lumpy at tick-over. I dont have access to a test tank or prop. I have been running it with the prop off and muffs fitted. Idle mixture screws work but dont make much difference to the tick-over lumpiness. Picks up fine and runs well at other speeds. Many new parts fitted including CDI, carbs fully rebuilt and adjusted. Compression 143 and 145psi.

Any ideas on fine tuning ?

Or is this just normal ?

Thanks Neil

[99yam40]

I believe Yamaha says to adjust final idle in gear when in the water.
and am sure with a prop on, other wise why in gear

not sure i ever seen carbs vacuum balanced in manual on that old of a motor or any place to hook it up to

[redexredex]

vacuum balance

Hi 99yam40,
thanks for the reply. I could not find a reference anywhere to vacuum balancing, just adjusting the top carb "cam" to match the connecting rod to synchronise opening of both butterflies.I thought it may be because my Yamaha was initially a re-badged version sold as a Mariner 60E and vacuum balancing unique to Mariner, however there is no mention in the Mariner manual either. However as the carbs are fitted with manifold port pipes, covered with rubber plugs, as on most motorcycles, I gave it a try. After setting the carbs manually I used vacuum gauges and found them to be miles out !!! Cant understand why Yamaha dont use vacuum gauges. My current motorcycle has 6 carbs (Honda Valkyrie F6C) and cannot be balanced without gauges !!!
I will follow your advice and set the tick-over, and idle screws, when I fit the outboard to my boat with prop attached.
Thanks for the reply.
I can post pics of the vacuum connections if you want to see them. The connections are on the manifold plates, between the carbs and reed valves, on the opposite side to the balance pipe.
If it works I have attached a pdf of the carbs, vacuum connections are part number 20. Didnt work too big hopefully the word doc will
Regards Neil

[redexredex]

carb balancing

Hi,
just a quick note to anybody trying a similar adjustment, the screw on the top carb "cam" has a LEFT HAND !!!!! thread, nearly stripped mine with a pair of mole grips before I checked.
Regards Neil