fuel not getting through the carb...

[sailhog]

Hi all,
I'm having fuel starvation problems.... I can't get the old girl started, as I'm not getting fuel to the combustion chambers. The electric fuel pump works fine. I've replaced the fuel line, cleaned both the racor and polishing filters, permatexed the fittings, cleaned the carb, replaced the float valve and the floats, replaced the carb gaskets... I have a new priming bulb, which is rock hard once fully primed.... still no fuel to the chambers.... I've got good compression, good spark....

The only things left to check, it seems, is the oil pressure safety switch and the manifold gasket...

Any hints from the learned panel?

[roadnsky]

Does the electric fuel pump "click"?
Go ahead and bypass the oil safety switch to check it.
If you disconnect the fuel line downstream of the fuel pump is there flow?

[sailhog]

Jerry,
Should I bypass the oil pressure safety switch by attaching a wire to its positive lead and attaching that to the positive lead of the fuel pump?

[ndutton]

Jumper the two terminals on the switch to bypass it. Can you confirm fuel in the carburetor bowl?

[sailhog]

Neil,
There has been fuel in the carb bowl when I've taken the carb apart to clean it. Not a lot.... but a few tablespoons comes pouring out of the carb...

[ndutton]

I'm wondering how the fuel got into the carb bowl, fuel pump or squeezie bulb? How did you determine the fuel pump was working properly? Jerry's oil pressure switch bypass should help answer that question.

With fuel in the bowl I also wonder about the status of the choke.

[sailhog]

Neil,
I determined the fuel pump was moving fuel a couple of weeks ago by removing the fuel line from the carb and then turning the engine over with a screwdriver on the starter leads. The pump seemed to produce plenty of fuel. The choke cable is in-op as the housing is corroded to the cable itself. When trying to start the engine, I've secured the choke in the closed position with the cable adjustment screw.

[roadnsky]

...With fuel in the bowl I also wonder about the status of the choke.

Excellent point!
Is your choke closing properly? ie. All the way?

[sailhog]

I THINK so. I need to confirm this.

[hanleyclifford]

OK, so you know you are getting fuel into the bowl and you are going to make sure that choke is closing all the way. Do you see any evidence of fuel puddling in the carb intake? After attempts to start there should be some. If not maybe the fuel is not getting past the main jet?

[ndutton]

Don't forget the standard admonition:

Be sure to keep the thru-hull closed until the issue is resolved.

[sailhog]

I removed the impeller so as not to damage it.... Is the main jet the one with the big removable nut on it? If so, that one is completely clear. I think ALL the smaller jets are clear, but it's difficult to be completely certain....

[Seaspot]

Does the electric fuel pump have enough pressure? That's one of the first things I'd check.

You could run a straight line from the pump to the carb to check if there is any obstruction between the tank and the carb.

[Dave Neptune]

Fuel ?

Sailhog, might I suggest a fuel preassure gage in front of the carb to confirm furl preassure, it will eliminate a lot of futzing around now and possibly in the future. Also do make sure that the choke is FULLY closed as otherwise an updraft carburated engie as the A-4 is hard to start at best.

One more idea an hopefully and a moot point. You stated you used permatex on the fittings. It is not necessarily a good idea to use it on fuel fittings especially at the carb. If you installed the seat and or the carb's hose bib with it you may have a glob of it holding the needle shut or in a fuel jet or worse yet a passage.

Dave Neptune

[chiron]

I chased around a fuel related problem such as yours for over a month and thinking that I had good spark I ignored the distributor cap and rotor. I eventually out of frustration replaced both and low and behold what I had thought was good spark had not been adequate enough. New cap rotor plugs and coil fixed my fuel starvation problems, and I got new fuel lines pump and rebuilt carb out of the deal. Just a thought from a newbie.

Chad