No Fuel to 1 Carb?

[Hardcore]

1994 140hp Evinrude Looper. Here is what is going on: When i try to prime the bulb when the line is connected to the motor it wont suck fuel from the tank, if i disconnect the line at the VRO it will suck fuel, if i get fuel into the VRO it will run but only on the port side cylinders, i have spark on all 4.

it seems that the problem is that it isnt getting fuel because it can't purge the air in the VRO or carb on the port system? unless i prime the carbs, no gas gets anywhere via the bulb. any ideas?

thanks in advance

 

[Joe Reeves]

Re: No Fuel to 1 Carb?

Sounds like the engine has sat for some time in a tilted position, tilted to one side. This (sometimes) results in having the carburetors on one bank foul, clog, gum up, leaving the opposite carburetors in a fairly runable condition.

If air can't get out of the carburetors or fuel line, fuel can't get in.

If this is the case, it is highly recommended that "all" carburetors be removed, cleaned thoroughly, and rebuilt in order to avoid a possible lean running condition on various carburetors that could lead to piston damage.

 

[Hardcore]

Re: No Fuel to 1 Carb?

Sounds like the engine has sat for some time in a tilted position, tilted to one side. This (sometimes) results in having the carburetors on one bank foul, clog, gum up, leaving the opposite carburetors in a fairly runable condition.

If air can't get out of the carburetors or fuel line, fuel can't get in.

If this is the case, it is highly recommended that "all" carburetors be removed, cleaned thoroughly, and rebuilt in order to avoid a possible lean running condition on various carburetors that could lead to piston damage.

actually no, it is always stored in the down position and also it was running fine for about 30 minutes before it lost 2 cylinders.

and also i always run the gas out.

 

[Silvertip]

Re: No Fuel to 1 Carb?

actually no, it is always stored in the down position and also it was running fine for about 30 minutes before it lost 2 cylinders.

and also i always run the gas out.

That last bit of info (always run the gas out) is a clue. 1) You cannot run ALL the gas out as the engine will quit before that happens. 2) More space for air in the carb with less fuel means a better chance for gum and varnish formation. 3) You may or may not use a fuel system treatment but if you don't, that also increases the chances of fuel related issues. 4) Make sure the primer bulb (output side) is oriented 45 degrees vertical or straight up for proper operation. 5) How are you proving that it is just one side of the engine that is not firing? 6) Have you worked on the fuel/oil pump and perhaps have it plumbed incorrectly?

 

[Joe Reeves]

Re: No Fuel to 1 Carb?

(Running Engine Out Of Gas)
(J. Reeves)

If the engine has but one carburetor, it's unlikely that running the engine out of gas would do any harm. When the carburetor runs out of the fuel/oil mixture, the engine stops running.

However, a engine that has more than one carburetor should simply be shut off. The reasoning is that the top carburetor will run out of fuel first due to gravity and the engine will continue to run on because of the still existing fuel in the other lower carburetors.

This results in having at least one aluminum piston running up and down a steel cylinder wall with improper or no lubrication. Not a good idea!

Also, on a VRO model..... when you run the fuel (gasoline) out, thre VRO is still pumping oil. This results in having raw oil being pumped into the carburetor float chambers which will not flow thru the carburetor passageways.

 

[Hardcore]

Re: No Fuel to 1 Carb?

i pulled plug wires and nothing changed on the starboard side, but did on the port side. also only the port head got warm and the starboard was cold.

the plumbing hasn't changed and the key here seems to me to be the fact that the primer bulb cannot pump any gas when hooked up but does when disconnected.

the compression is very good on this motor also.