my 1999 yamaha 100hp four stroke outboard fuel pumps have both stopped working at the same time. moter runs fine if you keep pumping the bulb to keep pressure up, but the pumps will not draw fuel.
Ok on that year they had bad fuel pumps, all their motors did, they used a bad plastic on it and now have updated themYou will need to gaskets alsoI would replace them and the fuel line and primer bulb to the motor and replace the fuel filterIf you post the fuel model number i will post the part numbers and prices for you
the fuel line and primer bulb are brand new. and the gaskets and diaphrams on the pumps are also good. the pumps are cam driven but are not pumping
so you took the lines off and then cranked the motor off and no fuel came out of them
OKcopy and paste the link belowhttp://www.boats.net/parts/search/Yamaha/Outboard/1999/F100TLRX/FUEL%201/parts.htmlsee if #31 can be moved with your finger or something to get into the fuel pump hole
yes, i cranked the motor with the pump off to see if the lever was moving to activate the pump.
and they did not move?
it did move
and you install new pumps?
ok then the spring in the pumps are bad or they worn down
on both pumps at the same time?
copy and paste the link belowhttp://www.boats.net/parts/search/Yamaha/Outboard/1999/F100TLRX/FUEL%201/parts.html#21 can wear down#22 can loose its tensionif you just installed new diaphragms you could have gotten the wrong ones
the pumps were rebuilt by an authorized yamaha dealer a year and half ago. i may have to break down and take it back in.
thanks for the info. i will keep working at it for awhile longer first.
ok, i bet they wore down again, unless the cam wore downtry and see if you can borrow a new oneif your over filled on oil they are bad again
Over a 15 years of working on all the brands of outboards.