Fuel problem, need advice

[USAFitz]

'71 Merc 650 (4cyl)

Hello all, I have a quick question that I can't find the answer to with search. I have replaced all gaskets and diaphragms with carb and fuel pump kits as well as run the wonderful Seafoam product through the engine using the procedures in the FAQs. Timing is good.

So here's what's happening. at WOT, after a little while, the engine wants to bog down and die. I pump the bulb and it speeds right up. After overhauling the entire engine, I don't know where else to go with this. Can anyone steer me in the right direction? Thanks again for your time!

 

[diaric]

Re: Fuel problem, need advice

if everything you repaired in the fuel system is good, you have a few options, all pretty easy. the fuel hose and or bulb could be old, hose can collapse on the inside when under suction. the vent on the tank could be plugging up. i've seen fairly new tanks collapse cause the vent wasn't working properly. the hose ends and or connector ends at the motor or tank could be worn. poor connection, little bit of fuel leaks or some air enters on suction and you can't get enough to keep it going at wot. service manual has illistrations for checking for wear. lastly, check all the fuel hoses on the motor, a cracking hose or loose connection can allow some air in which will show up more on high rpm performance

 

[USAFitz]

Re: Fuel problem, need advice

perfect. thanks for the tips. the bulb is basically new but the tank is old as dirt. it seems so simple but I don't think I would have caught it had you not said anything. thanks again.

 

[diaric]

Re: Fuel problem, need advice

your welcome, let us know what the culprit was