fuel delivery problems...

[frawg]

I'm new - be nice...

'70-something Merc. 500 2 stroke...
ran like a top...
started sputtering and stalling...
found HUGE crack in fuel line...
replaced with "cheap" new bulb and line...
still no good...
no good on either 6 gal. tank....
changed bulbs and hose clamps - still no good...
got new (good) new line with bulb (and new fitting at each end)...
ran awesome for 20 minutes at full throttle...
stopped to fish...
started up - same problem.... :-(
whenever it stalls out, the "fix" is to pump up the bulb... but even then, if I wait to long to give it throttle, it'll idle rough and stall out again....

I'm convinced it's something fairly stupid/obvious... but I can't find it (imagine that?)...

Looking through "FAQs"... I'm wondering what "fuel line sucking air at o'rings," means "exactly"?....

Please HELP!!! The kids want to ski and it's almost September!!! :-(

thanks...

 

[tmcalavy]

Re: fuel delivery problems...

Having to pump the bulb indicates a problem in the line from the tank to the outboard, or a bad fuel pump diaphragm. Check the pick up in your tanks and then the new lines/bulb you put in...maybe plug them up to another Merc as a test. I bet the fuel pump diaphragm is on its way out. Nice outboards those Merc 500's...wish I still had mine, but it had to go with the old boat.

 

[frawg]

Re: fuel delivery problems...

Okay... I believe you... now... Opening it up and looking, I note that the fuel line (where it enters the fuel pump) looks "iffy"... i.e. the rubber that lines the outside of the braided line is peeled away a bit from the brass fitting that should be crimped around it... That, alone, shouldn't be enough to suck air should it?... and, if it is, how do you discconect that hose at the front end, i.e., what is it there that has to be removed?... (looks "electrical" - not the starter motor? but?....) - just unbolt it?...

Or is the hose probably a "nothing" and I should just move on to the fuel-pump rebuild?...

Thanks...
Chuck