Pro 50 surge , poor acceleration

[TownsendsFJR1300]

Found the fuel pump gasket damaged at the pressure fitting
bolts holding the pump on the block were loose

could this cause the condition I have ?

Fuel leaking, fuel not pumping fully, YES...

[TownsendsFJR1300]

Using an ultrasonic heated cleaner with a good cleaning solution will vastly increase the backyardigans chance of getting it done right. The first time. IMO.

Which is a reason why Yamaha recommends them to the mechanics that work at Yamaha dealerships. Many Yamaha mechanics in title are not much more than backyardigans in their early stages of working on Yams.
.

I clean most carbs by hand(small engines, orifices, etc are MUCH smaller that outboard carbs).

On occasion, I'll come across one that after cleaning is still in not right...

It gets pulled apart again, dunked in the cleaner (just with dish soap and water) and let er "cook"...

I've found Simple Green and water (50/50) works ok but turns the aluminum carb body "dark". The water and soap alone seems to work very well.


Metal parts, 2-3 times, plastic parts, 2x's as the cleaning fluid heats up even with the heater off...

Well worth the $, saves time and usually more thorough.

[99yam40]

Found the fuel pump gasket damaged at the pressure fitting
bolts holding the pump on the block were loose

could this cause the condition I have ?

fuel pump not getting the pulses it needs to operate properly and the air leak to #3 crankcase would cause problems.
but I do not know if that is your only problem.
fix that and run it again to see

[Freaky1974]

Replaced the pump and the gasket

i can get an adjustment on the lower carb now - air/fuel mixture screw

sounds much better running too

going to test run it and report back

[Freaky1974]

One more quick question - the air/ fuel mixture screws - in is lean and out is rich ?

[TownsendsFJR1300]

One more quick question - the air/ fuel mixture screws - in is lean and out is rich ?

Clockwise (IN), is LEAN.

[walleye1]

Yes it can