HELP no fuel picking up has me stumped

[yama-doo]

I am no pro but I find my way around a engine build ok but this issue has me baffled it has to be a simple problem cause it is driving me absolutely crazy

B1 with a 701 single carb and I thought all I was waiting for was a waterbox but we tried to start it today motor turns over fine (plugs out) but I can't get any fuel picked up here are some of the things I have done trying to trace the problems down

1) blown out the fuel line to make sure there are no obstructions
2) removed the 46 carb and cleaned
3) removed the 46 carb again and replaced all new gaskets again just in case I had a pin hole somewhere
4) garbed a 44 crab off another engine and tried it , still no fuel being picked up (lines are dry)
5) bypassed the switch,filter connected the res line directly to the carb pick up still nothing
6) even swapped the return and pick up line to try that as nothing else was working I was drawing at straws

I feel like I eliminated the carb, blocked lines , it has half tank new fuel

So does anyone have any ideas what else I am missing? we have been playing with this for the last five hours

 

[tshank123]

you said you blew out the fuel lines, does that include the fuel tank pickup?

check the pulse line.

also, make sure the whole system is leak free by removing the return line and blowing into it while blocking the return from the carb with your finger.


Are you trying to draw fuel into the carb with the plugs out? Not sure, but you might need the plugs in.

 

[DAG]

many times my pickup line from the tank nipple inside the tank has worked itself off. make sure your lines are to the bottom of the tank

 

[yama-doo]

I just have the plugs out so the motor can spin over freely without killing the battery until I can get the fuel to start picking up, I don't "think" they are required for priming the engine/carb I have done other skis like that no problem

when I said blow out the lines I removed the fuel in for tank line and use compressed air it bubbles the gas and you know the line is clear. are you say to blow into the carb? if so I didn't do that on either carb


Dag,
I thought of that pulled out the pickups both tubes are free there is no filter inside I added a fuel line to the bottom of the "res" tube , both lines are submerged below the fuel

 

[Matt_E]

Pull the pulse line of the carb(s) and put your thumb over it. Then crank. You should feel the vacuum/air pulse.
If you don't, there's an engine problem.

Next, reinstall the pulse line and pull the fuel inline off the carb. Put your finger/thumb over the in nipple on the carb, then crank.
You should feel a pulse here, too.
If you don't, the problem is internal to the carb.

If everything checks out so far, your fuel lines/filter/tank have a problem.

 

[SUPERTUNE]

OK, lets just make sure you have a fuel supply to the carb.
2 lines off the tank, 1 for ON, 1 for RESERVE, both go to fuel selector, one out of selector on to fuel filter, then to carb, use the lowest fitting on the carb body for IN, the fitting inline with it and directly above, is the return line to the tank nipple. The fitting on the carb plate is the pulse line and connects to the top of the intake manifold (61X) or top of the cases (62T).
Put gas in tank about 1/3 full is fine, use a cup the catch fuel with, pull off the IN line from the carb and put in cup, next, pull off the return line from the carb and blow in the hose to put pressure in the tank with the fuel selector in the ON position you should see fuel flowing out of the line into the cup after about 15 seconds. Now connect this IN line back on the carb and now hold cup up to the return fitting at the carb, blow again in the return hose and less than 10 seconds you should have a small about coming out as the carb has a internal restrictor bleed, so the fuel won't be a lot, just a small trickle.
Now connect return line back on carb. Pull off the F/A, unscrew idle screw until throttle plate is closed, now cover with your hand and do a quick crank, quickly look down in carb and see if you have fuel.
If so, put together and fire up. should stay running when you set the idle up again.

 

[yama-doo]

Thanks everyone

ok I disconnected the pulse line hose form the carb, the engine side I can feel a strong pulse. I never primed one like that before but removed the return and put air to it worked good, spun it over it started to fire then nothing, maybe just some air pockets I'm going to let the battery charge back up and try again later .......... looking down in the carb I did not see fuel like I normally would when I push the throttle