712 almost starts; fuel delivery

[michaelh712]

Thanks Jim. Cleaned all jets, backed off solenoids (all working), and pulled carb top. Almost NO gas in bowls and little in accelerator pump.

Reading 2.6 lbs from outlet of pump, but only 1 oz or less output in 10 seconds. Inlet from tank is clear (blew air through and no obstructions), and no Austrian paperwork is floating around the tank as I have a 30 gal. ss tank I installed last year.

[Jim LaGuardia]

Did you remove the needle and seats and blow through all the lines going to the carbs?
If so, I would pull the pump apart and look at all the pieces, also check to see pump rod moves freely in the spacer block.

[michaelh712]

Removed needles, blew through all lines. Dissembled the fuel pump (rebuild was only 6 months ago), no leaks or obvious tears.
Bypassed the fuel tank with a temp tank and a strong stream from pump. Connected pump to main tank and strong stream for 2 seconds, then almost nothing. My deduction is that I have a bad connection between pump and tank (as tank is 1/2 full), or some kind of obstruction. I'll pull the observation plate and sender and take a look. If nothing obvious, I'll pull the tank and inspect the connections. Other ideas?

[M Wehrman]

Make sure there are no cracked fuel hoses between the tank and the pump...air can be sucked in causing lo flow. I had one Pinz that had no fuel smell,ran crappy and it was just a bad hose. Just a thought.
Mark

[Jim LaGuardia]

As I put in a previous post Just pull the sender and look inside,it only takes 5 min to do, you would be suprised at the things you find inside(found a happy meal toy in a tank once)
If you don,t see anything, it may be a fractured or obstructed suction pipe(unscrews from tank for easy replacement). You are finally narrowing it down.
Take a picture of what you find

[michaelh712]

Problem solved. Turned out to be small cracks in the hose ends where it connects to the pickup on the tank. These were hard to see until I pressed the hose in just the right way. Harder to diagnose as the problem was intermittent, but much worse under climing conditions and when warm.
Thanks to all for the expert help and suggestions.