Yamaha Malta problem!!

[davewill]

I have a Yamaha Malta outboard with a bit of a problem, it will only run with the choke full out. As soon as I put the choke in it cuts out straight away. I have just spent an hour or two in the garage with the carb striped down, cleaned out all the gunk from the float chamber and cleaned the jets out. I put it all back together and still the same, runs perfect with the choke out and revs well but, even if I put the choke in on full revs it cut’s out. Any idea’s.

 

[m1taylor]

This does sound like a fuel problem, so you have done the right thing by cleaning the carb. Sometimes it is easy just not to have cleaned it thoroughly enough - compressed air through the jet is quite good - I have used the aerosols you can buy for cleaning computer parts and it is very effective. Is your fuel fresh?

 

[sparkie]

It's almost certainly a fuel problem. If you've cleaned the carb and jets that's only half the job. Tank, line, filters, everything in the fuel system must be absolutely clean or it won't work. Also, as jimminy suggests, fresh fuel is essential these days due to the formulation of unleaded. A lot of petrol-heads in our harbour this year have had fuel problems, this new unleaded is very aggressive, and eats into ally carbs, leaving a v.fine white deposit as it does, which then blocks the jets.

Good luck

Sparkie

 

[Boathook]

Sounds like the idle jet is blocked. When looked through it should look round and clear. Any minor distortion when viewed means that it is still blocked. This also applies to the main jet. Also, is the idle jet screw unscrewed by 1.5 turns or there abouts for the idle jet to work ?

 

[davewill]

Thanks for the advise all. I’ll strip the carb again along with fuel lines & tank etc, get some more fresh petrol & see what happens. Thanks again.

 

[davewill]

Seems to have done the trick, now ticking over nicely. Thanks again.