1990 Yamaha Pro 50, loss of power problem

[mwniema]

I have a Yamaha 50 Pro, year =1990, I am experiencing a loss of power. It starts OK but it doesn’t idle to well, although it does stay running. It will run while in gear but only very slowly approx. 1500 rpm. It picks up speed after I hit the choke button, but only briefly. Any ideas?

 

[jim dozier]

Re: 1990 Yamaha Pro 50, loss of power problem

Pull the plugs 1 at a time (ground the loose plug wire) and see which if any cylinders aren't firing. If you can isolate a bad cylinder, first check the spark with a spark checker (inexpesively available at most auto parts stores). If it has spark, try squirting some premix in the carb throat while the engine is running under a load and see if it picks up any. If so you may have a clogged main jet. It is also possible that your fuel pump is crapping out. Try pumping the fuel bulb and see if that helps.

 

[mwniema]

Re: 1990 Yamaha Pro 50, loss of power problem

Thanks I'll try those suggestions tonight and see what happens.

 

[mwniema]

Re: 1990 Yamaha Pro 50, loss of power problem

Took it in to the shop, they rebuilt the three carbs and now it works fine. ...