w.o.t. question again

[pavlos]

Hi folks
I will try to keep this brief but Here goes...
have been given a pre 1980 yam 20A that I know has not run more than 15hrs!! tho it has not been run at all for last 4 years. having cleaned the carb out, checked plugs, replaced fuel pump it starts and ticks over fine and will rev its nuts off in neutral but as soon as its under load it just chokes, it will still run but it sounds like the choke is full on ( its not) and just has no power
what concerns me is the mixture screw is wound almost to the point of falling out but winding it in at all kills the tickover. any ideas?? fuel tank vent fine by the way and sqeezing primer makes no difference.

 

[pavlos]

Re: w.o.t. question again

it seems i was being a little nervous about undoing the mix screw while bobbing about in the sea, having checked again on dry land it is 2 and 3/4 turns out which i guess is about right????

 

[Yamajoe]

Re: w.o.t. question again

check your compression, check that you have good sparks, do your link and sinc and check static timing, you may need to clean the carbs as well.

 

[Silvertip]

Re: w.o.t. question again

Idle mixture screw should be only roughly set in the driveway running on muffs. There is no exhaust back pressure so the final adjustment MUST be done with the engine warm and in the water.

 

[pavlos]

Re: w.o.t. question again

having run the engine in a butt i now suspect timing but does anyone know where i might source a manual either in the uk or online? do i really have to go to a yam dealer?